Taxonomic revision of the genus Heliotropium (Boraginaceae s.l.) in south Yemen

Salah El Naggar , Azza El-Hadidy and Asmaa Olwey

S. M. El Naggar and A. O. Olwey (asmaa_olwey@yahoo.com), Botany and Microbiology Dept, Faculty of Science, Assiut Univ., Assiut, Egypt. – A. H. El-Hadidy, Botany Dept, Faculty of Science, Cairo Univ., Cairo, Egypt.

Th e fl ora and fauna of Arabia, particularly southern Yemen, has recently attracted the interest of many authors. In this study, the genus Heliotropium L. (Boraginaceae) is taxonomically revised in southern Yemen. Ten species are recognized. Nomenclature, typifi cation, representative specimens and a diagnostic key to all species are provided, along with their distribution in southern Yemen. Th e taxonomically most valuable characters in the genus are those of fl owers (calyx, corolla, androecium and gynoecium) and nutlets, and those characters are thoroughly investigated and discussed. Both light and scanning microscopy are used in the investigation. Papillate anther apices (brush-like) were recognized in some species. Connate anthers and deep or shallow ventral circular depressions on the nutlets were found to be useful in distinguishing members of H. sect. Orthostachys (viz. H. strigosum , H. rarifl orum and H. ovalifolium ), while winged nutlets were found only in H. pterocarpum . Th e length and hairiness of the style and stigma also proved to be taxonomically useful.

Boraginaceae s.l. is one of the largest families of dicoty-ledonous angiosperms. On the account of its broadly drawn limits, it faces some debate on both the ordinal and the infra-familiar levels. It was placed in an uncer-tain ordinal position by the Angiosperm Phylogeny Group, APG III (2009) [Eudicots – Asterids, subgroup Euasterids I]. Th e phylogenetic relationships within the family are still unclear. Currently, a concept of six sub-families (Codonoideae, Wellstedioideae, Cordioideae, Ehretioideae, Heliotropioideae and Boraginoideae) is still widely accepted. However, a taxon of ordinal rank (Boraginales), comprising six smaller families (Boraginaceae s.s., Hydrophyllaceae, Heliotropiaceae, Cordiaceae , Ehre-tiaceae, Codonaceae and Wellstediaceae) is increasingly being used instead of Boraginaceae s.l ( B ö hle and Hilger 1997, Ferguson 1999, Smith et al . 2000, Gottschling et al . 2001, 2004, Stevens 2001, Hilger et al. 2005, Cohen 2013, Refulio-Rodriguez and Olmstead 2014, Weigend et al. 2014).

Th e terminal style (in contrast to the gynobasic style of sub-family Boraginoideae), and its uniquely modifi ed stigmatic head that consists of a basal annulus and a conical infertile apex, are the best characters distinguishing the sub-family Heliotropioideae. Recently, a phylogenetic analysis using data obtained by trnL and ITS 1 gene sequences supported the idea of raising Heliotropioideae to the familiar rank as Heliotropiaceae Schrad. (Diane et al . 2002, Hilger and Diane 2003). At the same time, generic limits have also changed dramatically. Within Heliotropiaceae Schrad, a

system of fi ve genera was initially suggested: Euploca Nutt., Heliotropium L., Ixorhea Fenzl, Myriopus Small and Tourne-fortia L. Recently, the genus Euploca Nutt. has increasingly accepted as a valid genus (Melo and Semir 2006, 2009, 2010, Melo et al. 2009, Acevedo-Rodr í guez and Strong 2012, Degen Naumann and Melo 2012), While,the validity of the genus Tournefortia L. as a separate genus has become questioned and some authors prefer to nest it within Heliotropium L. (Craven 2005, Luebert et al. 2011).

Recently, biogeographers have recognized the south-western region of the Arabian Peninsula and southern Yemen as a part of the fl oristic hotspot the African Horn (Mittermeier et al . 1998, Myers et al. 2000). Heliotropium L. in Arabia, and particularly in Yemen, has always been problematic. Many species exhibit great polymorphism that make them hard to identify accurately. Hence, the number of Heliotropium species accepted as represented in Yemen has changed through time. Forssk å l (1775) was the fi rst to report 5 taxa belonging to Heliotropium in the area, while and Defl ers (1889) recorded 7 species . Recently, Gabali and Al-Gifri (1990) recorded 10 species, Wood (1997) reported the presence of 12 species, while Boulos (1988) accepted 9 species and two subspecies.

Th e present study aims were to: 1) revise the diff erent taxa belonging to Heliotropium L. in the fl ora of Yemen, 2) evaluate the taxonomic characters and attempt to fi nd new ones that can be used in the classifi cation of the genus in the region, and 3) provide a revised synopsis and a diagnostic key for the genus in Yemen.

© 2015 Th e Authors. Nordic Journal of Botany © 2015 Nordic Society Oikos Subject Editor and Editor-in-Chief: Torbj ö rn Tyler. Accepted 5 December 2014

Nordic Journal of Botany 000: 001–013, 2015 doi: 10.1111/njb.00746, ISSN 1756-1051

Early View (EV): 1-EV

Material and methods

Plant material

Morphological data of Yemen taxa of Heliotropium were scored by examination of herbarium specimens collected from diff erent localities in southern Yemen, representing diff erent habitats, and kept at ASTU. Some Saudi Arabian specimens were also investigated. High quality digital photos of type specimens and authentic material were seen by the authors as indicated by (!) in the text.

Light microscopy Willd 8 and Willd 3 Zewz stereomicroscopes were used. Illustrations were made with a Camera Lucida and photographs with a Canon IXUS 960 IS digital camera.

Scanning electron microscopy (SEM) Material for SEM were prepared by mounting plant segments onto clean stubs using double-sided cellotape. Th e stubs were coated with gold in a JEOL JFC 1100 E ion sputtering device, and then examined in a JEOL JSM 5400LV scanning electron microscopy operated at an accelerated voltage of 15 kV at the Electron Microscopy Unit (EMU), Assiut Univ., Egypt. Terminology follows Lawrence (1959), Radford et al . (1974) and Harris and Harris (1994).

Synopsis of the genus Heliotropium L. in south Yemen

Th e infra-generic classifi cation proposed by F ö rther (1998) is followed here as outlined below, with the species (num-bered) represented in Yemen indicated within each section and subsection.

Heliotropium L. (1753, p. 130)

Taxonomic synonyms : Euploca Nutt. (1837, p. 189). – Piptoclaina G. Don (1837, p. 364). – Heliophytum (Cham.) A. DC. in DC. (1845, p. 551).

I. Section Heliotropium 1. Heliotropium europaeum L.

II. Section Orthostachys R. Br. A. Subsect. Bracteata I. M. Johnst.

2. Heliotropium strigosum Willd. i. var . strigosum ii. var . brevifolium (Wall.) C. B. Clarke

3. Heliotropium rarifl orum Stocks B. Subsect. Ebracteata I. M. Johnst.

4. Heliotropium ovalifolium Forssk. III. Section Pseudocoeloma F ö rther

5. Heliotropium abyssinicum Vatke IV. Section Pterotropium (A. DC.) Bunge

6. Heliotropium bacciferum Forssk. 7. Heliotropium ramosissimum (Lehm.) Sieb. ex A. DC.

8. Heliotropium pterocarpum (A. DC.) Hochst. & Steud. ex Bunge

V Section Rutidotheca (A. DC.) Verdc. 9. Heliotropium longifl orum (A. DC.) Jaub. & Spach

subsp. longifl orum i. var. longifl orum ii. var. stenophylum (O. Schwartz) Verdc.

VI. Section Zeylanica F ö rther 10. Heliotropium zeylanicum (Burm. f.) Lam.

Key to the species

1 Corolla completely yellow, or yellowish green; anthers bidentate … … … … … ……………… 10. H. zeylanicum – Corolla completely white, or tinged with yellow at the throat; anthers not bidentate … … … … … … ………… 2

2 Infl orescence bracteate; calyx-lobes unequal; nutlets with ventral cavities … … .. … … … … … .. … … … … .......… 3 – Infl orescence ebracteate; calyx-lobes equal or not; nutlets with or without ventral cavities . … ...…………… 4

3 Subshrubs or herbs; bracts prominent; corolla 1.5 – 2.0 ( – 2.5) mm long; anthers with erect apiculate apex; stigma depressed … … … … … … ……… 3. H. rarifl orum – Herbs; bracts reduced upwards; corolla 2.0 – 4.0 mm long; anthers with curved apiculate apex, stigma not depressed … .. … ....…………………… 2. H. strigosum

4 Corolla 3.0 – 5.0 mm long; nutlets 4 … .... … ………… 5 – Corolla 5.0 – 7.0 mm long; nutlets 2 or 4 . … … .…… 8

5 Style obsolete; stigma � sessile . … … . … … …………… 6 – Style at least 0.2 mm long … … . … ………………… 7

6 Greyish herb; calyx-lobes unequal with one large sepal; corolla hairy inside; anthers connate when young; stigma with apical hairs; nutlets with ventral cavities … … … . … … .. … ... … ………………… 4. H. ovalifolium – Green herb; calyx-lobes equal; corolla glabrous inside; anthers not connate; stigma glabrous; nutlets without cavities … … … ........ … ……………… … 1. H. europaeum

7 Flowers lax, in 1-rank, swollen at the base; anther ovate, inserted 1.00 – 1.25 mm from the base; style 0.2 – 0.5 mm long; stigma 0.50 – 0.75 mm long, glabrous, longer than the style … .. … … … .……………… 7. H. ramosissimum – Flowers dense, in 2-ranks, swollen at the middle; anther oblong-lanceolate, inserted 0.5 – 1.0 mm from the base; style 0.5 – 0.7 mm long; stigma 0.7 – 1.0 mm long, gla-brous, or with few scattered hairs, equaling or longer than the style … … . … ……………………. 6. H. bacciferum

8 Nutlets 2 (2-seeded), with symmetric groove at apex; leaves 0.5 – 4.0 � 0.3 – 2.0 cm … … … … ... … .………… 9 – Nutlets 4 (1-seeded), without groove; leaves longer and wider, up to 10.0 cm long and 7 cm wide . … ………………………………………… 9. H. longifl orum

9 Greyish annual; calyx-lobes unequal; stamens inserted below the middle of the corolla-tube; anthers 1.0 – 1.5 mm long; style 0.5 – 0.7 mm long; nutlets narrowly to broadly winged … ...………………. 8. H. pterocarpum – Green perennial; calyx-lobes equal; stamens inserted above the middle and reaching the throat; anthers 0.75 – 1.00 mm long; style 1.5 – 2.0 mm long, nutlets without wings … … … ………………………… 5. H. abyssinicum

2-EV

Figure 1. Habit of (a) H. europaeum , (b) H. strigosum var. strigosum , (c) H. strigosum var. brevifolium , (d) H. rarifl orum , (e) H. ovalifolium . Scale: 1 cm in (a), 5 cm in the rest.

1. Heliotropium europaeum L. (1753, p.130) (Fig. 1a)

Literature : Boiss. (1875, p.130), Blatter (1922, p. 309), Schwartz (1939, p. 206), Tutin (1973, p. 85), Wood (1997, p. 238).

Type : Europe: Netherlands, G. Cliff ord s.n. (lectotype: BM, BM000557900!), cultivated material from the gar-den of George Cliff ord III: Hartekamp Garden, Holland (designed by F ö rther), for typifi cation see Jarvis (1993, p. 57): Heliotropium follis ovatis integerrimis, spicis conjunctis .

Taxonomic synonym : H. majus Garsault (1764, t. 299) [nom. inval.].

Description Annual to prennial herb, 20 – 50 cm high. Stem � terete, erect, much branched. Leaves ovate to elliptic, 1.0 – 4.0 � 0.5 – 2.0 cm; apex obtuse; base cuneate; margin entire; petiole 0.5 – 3.5 cm. Infl orescence 2.0 – 7.0 cm long, dense, with

10 – 32 fl owers in 2-ranks; fl owers ebractaete, sessile. Calyx 5-lobed; lobes fused close to the base, equal, lanceolate to linear-oblong, 1.5 – 3.0 mm � 0.5 – 1.0 mm, hairy outside, glabrous inside. Corolla white, 2.0 – 3.5 mm, hairy outside on tube, glabrous inside; tube 1.5 – 2.5 mm long; lobes oblong-ovate to orbicular, 0.5 – 0.7 mm long. Stamens inserted at 0.8 – 1.0 mm from the base; anthers ovate, 1.00 – 1.25 mm long, apex � acute and papillate; fi lament indistinct. Ovary globose to subglobose; style absent, stigma elongate conical to conical-subulate, 0.75 – 1.25 mm, deeply 2-fi d at apex, glabrous. Fruit of 4 nutlets; nutlets ovoid, 1.5 – 2.5 � 1.0 – 2.0 mm, hairy, tuberculate-rugose.

Distribution Mediterranean area northwards to central and southern Europe; Asia: south Russia, Caucasia, Iran, Turkey, Afghani-stan, Pakistan and India; Saudi Arabia (Najran and Al Damam) and north Africa (especially in Libya). Yemen: Taiz, Lahj, Dhamar, Sanaa, Ibb and Hiddah.

3-EV

Heliotropium strigosum var. brevifolium : Yemen. Hamood s.n., Tor El-Baha, Jun 2012; El Naggar and Hamood s.n., Top of Jisr Akan (Akan Bridge), 1 Jun 2012.

3. Heliotropium rarifl orum Stocks (1852, p. 174) (Fig. 1d)

Literature : Boiss. (1875, p. 144), Verdc. (1991, p. 70), Collenette (1991, p. 91), Wood (1997, p. 239), Th ulin (2006, p. 50).

Type : Pakistan, Scinde, Jemadar Ka Landa near Kurrachi [Karachi], Stocks 492, 1851 (lectotype: K). For typifi cation see Akhani and F ö rther (1994, p. 260).

Taxonomic synonym : H. pseudostrigosum Dinter (1922, p. 250).

Description Strigose subshrub or perennial herb with woody base, 40 – 80 cm high. Stem terete, erect, much-branched; branches with white peeling epidermis. Leaves lanceolate to linear, 0.4 – 2.0 � 0.1 – 0.5 cm; apex acute; base cuneate; margin revolute; sessile or shortly petioled with petiole up to 0.1 cm long. Infl orescence lax, 1.3 – 9.0 cm, of 6 – 20 fl owers in 1-rank; fl owers bracteate and pedicelled; bracts linear-lan-ceolate, 1.5 – 2.5 mm; pedicel 0.5 – 1.0 mm. Calyx 5-lobed; lobes fused close to the base, unequal, lanceolate to ovate, 1.0 – 2.0 � 0.5 – 1.0 mm, hairy outside, glabrous inside. Corolla white, 1.5 – 2.5 mm, hairy outside and inside; tube 1.5 – 2.0 mm; lobes ovate to oblong, 0.5 – 1.0 mm, curved inwards. Stamens inserted 1.00 – 1.25 mm from the base; anthers connate when young, ovate, 0.5 – 1.0 mm long, api-culate at apex, with connective tissue prolonged and erect; fi lament ca 0.1 mm long. Ovary subglobose; style 0.5 – 0.1 mm, papillate, two to three times longer than stigma; stigma depressed capitate/conical, 0.2 – 0.5 mm, entire at apex, pap-illose and with apical tufts of hairs. Fruit of 4 nutlets; nutlets ovoid, (1.0 – ) 2.0 – 2.5 � 1.0 – 1.5 mm, hairy, with two ventral circular depressions.

Note According to Verdcourt (1991), H. rarifl orum can be divided into two subspecies: subsp. rarifl orum and subsp. hereoense (Schinz) Verdc. Th is classifi cation is based upon nutlet hairs. Our specimens are characterized by spreading bristly hairs on nutlets which matches subspecies rarifl orum .

Distribution Northeast tropical Africa (in Dijouti, Eritrea, Ethiopia, Sudan and Somalia); tropical Africa (in Kenya, Tanzania, Angola and Namibia); Arabia (Saudi Arabia: Asir); Asia (Iran and Pakistan). Yemen: Lahj, Aden, Abyen and Socotra.

Specimens examined Yemen. Hamood s.n., Tor El-Baha, 2012.

4. Heliotropium ovalifolium Forssk. (1775, p. 38) (Fig. 1e)

Literature : Blatter (1922, p. 310), Schwartz (1939, p. 205), Verdc. (1991), Wood (1997, p. 238), El-Hadidy and Boulos (2000, p. 277), Th ulin (2006, p. 50).

Specimens examined Yemen. Hamood s.n., Tor El-Baha, 2 Feb 2011; El Nag-gar s.n., Taiz,; Apr 2009; El Naggar s.n., Taiz, Mar 2005; El Naggar s.n., El-Hoban 2008; El Naggar s.n., El-Hoban, May 2007.

2. Heliotropium strigosum Willd. (1798, p. 743) (Fig. 1b – c)

Literature : Boiss. (1875, p. 143), Blatter (1916, p. 254, 1922, p. 311), Collenette (1991, p. 92), Verdc. (1991, p. 72), Wood (1997, p. 239), El-Hadidy and Boulos (2000, p. 276 – 277), Th ulin (2006, p. 51).

Based on the same type : Euploca strigosa (Willd.) Diane & Hilger (2003, p. 49).

Type : Ghana [Guinea], Isert s.n. (holotype: B, B-WILLD 3253, isotypes: C, C10003972!; P, P-JU 6571).

Two varieties of H . strigosum can be recognized in Yemen:

1 Bracts linear-lanceolate (1.0 – 2.0 mm wide); corolla lobes triangular; nutlets small (1.0 – 1.2 mm) … … var. strigosum – Bracts ovate (2.0 – 3.0 mm wide); corolla lobes rounded; nutlets large (1.3 – 1.5 mm) ...... … … … … var. brevifolium

Description Annual herb or short-lived perennial with woody base, 5 – 40 cm high. Stem � terete, much-branched; branches prostrate to erect. Leaves lanceolate to linear or narrowly elliptic, 0.5 – 4.0 � 0.1 – 0.5 cm; apex acute; base cuneate; margin revolute; petiole 0.1 – 0.2 cm. Infl orescence lax, 1.5 – 8.5 cm, of 5 – 15 fl owers in 1-rank; fl owers bracte-ate (bract 1.0 – 3.0 mm), subsessile or shortly pedicelled; pedicle 0.5 – 1.5 mm. Calyx 5-lobed; lobes fused close to the base, unequal, ovate to narrowly elliptic, 1.5 – 3.0 � 0.50 – 0.75 mm, hairy outside, glabrous inside. Corolla white, 2.5 – 4.0 mm, hairy outside on lobes and upper part of tube, hairy inside above the anthers; tube 2.0 – 3.0 mm; lobes triangular or rounded to oblong, 0.5 – 1.0 mm. Stamens inserted 1.00 – 1.25 mm from the base; anthers connate when young, ovate, 0.75 – 1.00 mm, their apex apicu-ate and hairy, with connective tissue prolonged and curved; fi lament ca 0.1 mm. Ovary globose to sublo-bose; style 0.25 – 0.50 mm, glabrous; stigma short coni-cal, (0.30 – ) 0.50 – 0.75 mm, 4-lobed at apex, hairy and papillose, longer than or equal to the style. Fruit of 4 nutlets; nutlets ovoid, 1.0 – 1.5( – 2.0) � 0.5 – 1.0 mm, hairy, with two deep ventral circular depressions.

Distribution Egypt; tropical region of Africa; Saudi Arabia (Najran and Hejaz); Asia: Pakistan, Iran, India and Sri-Lanka; and eastern Asia: China and Japan. Yemen: Taiz, Lahj, Tihama, Abyen, Hadhramaut and Socotra.

Specimens examined Heliotropium strigosum var. strigosum : Yemen. El Naggar s.n., Habil Al-Salman Taiz, Nov 2008; El Naggar s.n., Habil Al-Salman Taiz, 10 Oct 2008; El Naggar s.n., Jabal Sabr-Taiz, Apr 2008; El Naggar s.n., Wadi Al-Quadi, Taiz, Apr 2008; El Naggar s.n., El-Hoban, Oct 2006.

4-EV

lanceolate to lanceolate-oblong, 1.5 – 2.0 � 0.2 – 0.4 mm, hairy outside, glabrous inside. Corolla white with green center, 4.0 – 7.0 mm, hairy outside, glabrous inside; tube 3.5 – 4.0 mm; lobes ovate, 1.5 – 2.0 mm. Stamens inserted 2.25 – 2.50 mm from the base; anthers oblong, 0.75 – 1.00 mm, acute at apex; fi lament indistinct. Ovary glo-bose to subglobose; style 0.5 – 2.0 mm, glabrous, distinctly longer than stigma; stigma elongate conical, 0.5 – 1.0 mm; apex shortly 2-fi d, glabrous. Fruit of 2 nutlets; nutlets broadly ovoid and shallowly notched at apex and base, 2.0 – 2.5 � 1.5 – 2.0 mm, with a shallow groove at the middle from apex to base, laterally constricted near apex, hairy, rugulose.

Distribution Northeast tropical Africa: Somalia, Ethiopia and Sudan. Yemen. Taiz, Lahj, Sana’a El-Hoban and Hadhramaut.

Specimens examined Yemen. El Naggar and Hamood s.n., Taiz, 31 May 2012; El Naggar and Hamood s.n., Tor El-Baha, Lahj, May 2012; El Naggar and Hamood s.n., Hida, 27 May 2012; Hamood s.n., Tor El-Baha, 14 Nov 2009; El Naggar s.n., Taiz, Nov 2009; El Naggar s.n., Habil Al-Salman Taiz, Oct 2008; El Naggar s.n., El-Hoban, Jun 2007; El Naggar s.n., Taiz, Oct 2006.

6. Heliotropium bacciferum Forssk. (1775, p. 38) (Fig. 2b – c)

Literature : Blatter (1922, p. 308), Schwartz (1939, p. 211), Collenette (1991, p. 89), El-Hadidy and Boulos (2000, p. 279).

Type : Arabia: Yemen; Lahaja [Al Luhayyah], 1.1763, Forssk å l 1329 (C, C10002532, microfi che foto!; isotype: BM, KIEL). See Hepper and Friis (1994) and F ö rther (1998) for details.

Taxonomic synonyms : Lithospermum hispidum Forssk. (1775, p. 38). – Heliotropium crispum Desf. (1798, p. 151, t. 41). – H. undulatum Vahl (1790, p. 131) [nom. illeg.], Boiss. (1875, p. 147), Schwartz (1939, p. 206).

Description Perennial herb, 20 – 40 cm high, woody at the base, covered by scabrous indumentum. Stem terete, much-branched; branches erect or ascending. Leaves lanceolate to linear, 0.5 – 3.0 � 0.5 – 1.5 cm; apex acute; base cuneate or attenuate; margin undulate-crenate and revolute; petiole 0.0 – 1.0 cm. Infl orescence dense, 0.5 – 4.2 cm, of 5 – 13 fl owers in 2-ranks; fl owers ebracteate, sessile. Calyx 5-lobed; lobes free almost to the base, equal, ovate-oblong or lanceolate, 1.0 – 3.0 � 0.50 – 0.75 mm, hairy outside and in the upper part inside. Corolla white, 3.0 – 5.0 mm, hairy on tube outside, glabrous inside; tube 2.0 – 4.0 mm; lobes ovate to oblong or suborbicular, 0.5 – 1.5 mm. Stamens inserted 0.5 – 1.0 mm from the base; anthers oblong-lanceolate, 0.75 – 1.00 mm, acute or shortly apiculate at apex; fi lament indistinct. Ovary ovate; style 0.4 – 0.7 mm, glabrous; stigma elongate conical, 0.7 – 1.0 mm (with stigmatic ring 0.1 – 0.2 mm high), 2-/4-lobed or 2-fi d at apex, glabrous or with few scattered hairs, equaling or lon-ger than style. Fruit of 4 nutlets; nutlets ovoid to elliptic,

Type : [Yemen]; Al-Hadiyah [Had ï e], 3.1763 Forssk å l 299 (holotype: C, C10002362!, isotype: BM).

Taxonomic synonym : H. kunzei Lehm . (1823, p. 19), Boiss. (1875, p. 130).

Description Greyish herbaceous annual or short-lived perennial, 10 – 90 cm high, woody at the base, covered with appressed hairs. Stem � terete, much-branched; branches procumbent or erect to ascending. Leaves ovate or elliptic, 0.5 – 5.0 � 0.3 – 3.0 cm; apex acute; base attenuate; margin entire; petiole 0.2 – 2.0 cm. Infl orescence dense, 2.0 – 10.0 cm, of 10 – 30 fl owers in 2-ranks; fl owers ebracteate, subsessile or shortly pedicelled with pedicle 0.5 – 1.5 mm. Calyx 5-lobed; lobes fused close to the base, unequal with one lobe distinctly larger, ovate to lanceolate-oblong, 1.0 – 3.0 � 0.2 – 0.8 mm, hairy outside, glabrous inside. Corolla white, 3.0 – 5.0 mm long, hairy outside and inside; tube 2.0 – 4.0 mm; lobes ovate to oblong or elliptic, 0.5 – 1.0 mm. Stamens inserted 0.75 – 1.00 mm from the base; anthers connate when young, ellip-tic to ovate, 0.5 – 1.0 mm long, apiculate and hairy at apex, with connective tissue prolonged, elongated and curved; fi lament indistinct. Ovary subglobose; style absent; stigma short conical, 0.5 – 1.0 mm, 2-lobed at apex, papillose and with apical hairs. Fruit of 4 nutlets; nutlets ovoid to ellip-tic, 1.0 – 2.0 � 1.0 – 1.5 mm, hairy, with two ventral circular depressions.

Distribution North Africa: Egypt and Libya; Arabia (Oman: Dhofan); southeast Asia; tropical Africa: Somalia, New Guinea, Madagascar and Mascarene Islands; with slight extension to Australia and Europe (in Turkey). Yemen: Taiz, Bura’a, Lahj, Tihama and Socotra.

Specimens examined Yemen: Hamood s.n., Tor El-Baha, 27 Oct 2010; Hamood s.n., Tor El-Baha, 10 Oct 2009; El Naggar s.n., Bura ’ a Reserve, Nov 2007; El Naggar s.n., Taiz, Mar 2007; El Nag-gar s.n., Jan 2006; El Naggar s.n., Jan 2005; El Naggar s.n., Wadi Bara, Mar 2006.

5. Heliotropium abyssinicum Vatke (1875, p. 168) (Fig. 2a)

Type : Abyssinia: Habab in locis sterilibus, Aug 1872, 7000, Aug 1872, Hildebrandt 470/b (holotype: B, isotypes: BM, LE, W).

Taxonomic synonym : H. bottae Defl ers (1889, p. 172, t. 5), Blatter (1922, p. 308), Schwartz (1939, p. 205), Wood (1997, p. 238).

Description Perennial herb, 10 – 100 cm high, woody at the base. Stem terete, branched; branches erect to ascending. Leaves broadly ovate, 0.5 – 4.0 � 0.3 – 2.0 cm; apex acute; base cuneate; margin undulate; petiole 0.5 – 2.0 cm. Infl orescence lax, 1.1 – 6.0 cm, of 10 – 27 fl owers in 2-ranks; fl owers ebracteate, sessile. Calyx 5-lobed; lobes free almost to the base, equal,

5-EV

Figure 2. Habit of (a) H. abyssinicum , (b) – (c) H. bacciferum , (d) – (e) H. ramosissimum , (f ) H. pterocarpum , (g) H. longifl orum , (h) H. zeylanicum . Scale: 1 cm in (a), (e), (g), (h), 5 cm in (d), (f ), 15 cm in (b).

1.5 – 2.0 � 0.75 – 1.00 mm, with narrow wing-like margins, hairy or glabrous, often with corky tissue, rugulose.

Distribution Extending from Egypt in Meditterranean north Africa east-wards to Pakistan, southwards in Sudan and northeast Africa and in Saudi Arabia(Asir). Yemen: Taiz, Ibb, Sana’a, Tihama and Hadhramaut

Specimens examined Yemen. El Naggar and Hamood s.n., Taiz, 31 May 2012; El Naggar and O. Hamood s.n., Sana’a Univ. ground, 25 May 2012; El Naggar and Hamood s.n., Wadi Al-Eshsh; May 2012; Hamood s.n., Tor El-Baha, 2012; Hamood s.n., Tor El-Baha, 3 Jan 2010; El Naggar s.n., Jabal Sabr, Taiz, Oct 2006; El Naggar s.n., Ibb, Jul 2006; El Naggar s.n., Habil Al-Salman, Taiz, Oct 2008; El Naggar s.n., Taiz, Oct 2008; El Naggar s.n., Taiz, Nov 2007.

7. Heliotropium ramosissimum (Lehm.) Sieb. ex A. DC., in DC. (1845, p. 536) (Fig. 2d – e)

Literature : Collenette (1991, p. 91), Wood (1997, p. 239), El-Hadidy and Boulos (2000, p. 280).

Basionym : H. undulatum Vahl var . ramosissimum Lehm. (1831, p. 24, t.40).

Type : Egypt, Wadi Gamuhs, Sieber s.n. (isotype: K; GH, GH00097757!).

Taxonomic synonym : H. persicum Boiss. (1875, p. 147), non Lam. (1789). Schwartz (1939, p. 207).

Description Perennial herb, 20 – 50 cm high, woody at the base, covered by scabrous indumentum of simple hairs associated with white sharp bristles. Stem terete, much-branched; branches erect

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or ascending. Leaves elliptic, 0.5 – 3.0 � 0.5 – 1.5 cm; apex acute; base cuneate or attenuate; margin undulate-crenate to entire and revolute; petiole 0.0 – 1.0 cm. Infl orescence lax, 0.5 – 1.5 cm, of 5 – 14 fl owers in 1-rank; fl owers ebracteate, sessile. Calyx 5-lobed; lobes free almost to the base, equal, lanceolate-oblong to lanceolate, 1.0 – 3.0 � 0.50 – 0.75 mm, hairy outside, hairy inside. Corolla white, 3.0 – 5.0 mm long, hairy on tube outside, glabrous inside; tube 2.0 – 4.0 mm long; lobes ovate to oblong or suborbicular, 1.0 – 2.0 mm. Stamens inserted at 1.00 – 1.25 mm from the base; anthers ovate, 0.75 – 1.00 mm long, apex acute or shortly apiculate; fi lament indistinct. Ovary globose to ovate; style 0.2 – 0.5 mm, glabrous; stigma elongate-conical, 0.50 – 0.75 mm, 2-(4-)lobed at apex, glabrous, equaling or longer than style. Fruit of 4 nutlets; nutlets ovoid, 1.0 – 1.5 � 0.75 – 1.00 mm, with narrow wing-like margins, hairy or glabrous, rugulose.

Distribution Extending from India westwards through Iran, Afghani-stan and southwest Asia to Palestine, Egypt (Sinai); across north Africa to Morocco and southwards to northeast Africa, and in eastern and northeastern Arabia. Yemen: Jisr Akan between Taiz and Lahj, Socorta.

Specimens examined Yemen. El Naggar and Hamood s.n., Top of Jisr Akan (Akan Bridge), 1 Jun 2012.

8. Heliotropium pterocarpum (A. DC.) Hochst. & Steud. ex Bunge (1869, p. 331) (Fig. 2f)

Literature : Blatter (1916, p. 256, 1922, p. 311), Schwartz (1939, p. 205), Collenette (1991, p. 91), Wood (1997, p. 238), El-Hadidy and Boulos (2000, p. 279), Th ulin (2006, p. 49).

Basionym : Heliophytum pterocarpum A. DC. in DC. (1845, p. 552).

Type : Arabia, in planitie deserti prope Dscheddam, 29 Feb 1836. Schimper 835 (ed. 1, 1837, ed. 2, 1843) (holotype: G-DC, syntype: K).

Taxonomic synonym : Heliotropium deserti Vatke (1875, p. 166).

Description Annual herb, 10 – 55 cm high, covered with scabrous indu-mentum of white bristles intermixed with simple defl exed hairs. Stem terete, simple or branched; branches prostrate to ascending. Leaves rhombic-ovate, 0.5 – 3.5 � 0.3 – 1.5 cm; apex acute or obtuse; base attenuate; margin undulate-crenate; petiole 0.2 – 0.5 cm. Infl orescence very dense and crowded, 0.5 – 1.2 cm long, of 8 – 14 fl owers in 2-ranks; fl ow-ers ebracteate, sessile. Calyx 5-lobed; three lobes free almost to the base and two connate almost to the top, unequal, oblong to linear, 3.5 – 4.5 � 0.5 – 1.0 mm, hairy outside and inside. Corolla white, (3.5 – ) 4.0 – 7.0 mm, hairy on tube outside, glabrous inside; tube 3.5 – 5.0 mm; lobes ovate, 0.8 – 2.0 mm long. Stamens inserted 1.5 – 2.0 mm from the base; anthers lanceolate, 1.0 – 1.5 mm, acute or apiculate at apex; fi lament indistinct. Ovary subglobose to elliptic; style 0.5 – 0.7 mm,

glabrous; stigma elongate conical, 0.4 – 0.6 mm, obscurely 4-lobed at apex, papillose, equaling or shorter than style. Fruit of 2 nutlets; nutlets � oblong (excluding wings) and with a deep sinus at apex and base, 2.0 – 3.0 � 3.0 – 4.0 mm (excluding wings), winged (narrow to broad, wings 1.0 – 3.0 mm wide), glabrous, minutely tuberculate to rugulose.

Distribution North Africa: Egypt; western Arabia; northeast tropical Africa through Sudan and Ethiopia. Yemen: Jisr Akan, Lahj, Taiz, Tihama and Hadhramaut.

Specimens examined Yemen. El Naggar and Hamood s.n., Top of Jisr Akan (Akan Bridge), 1 Jun 2012; El Naggar and Hamood s.n., Wadi El-Dabab, Hifan, Taiz, May 2012; Hamood s.n., Tor El-Baha, 2012; El Naggar s.n., Habil Al-Salman, Taiz, Oct 2008; El Naggar s.n., Al-Anabi, Jan 2008; El Naggar s.n., Habil Al-Salman, Taiz, Oct 2006.

9. Heliotropium longifl orum (A. DC.) Jaub. & Spach (1852, p. 96, t. 360) subsp. longifl orum (Fig. 2g)

Literature : Blatter (1922, p. 309), Schwartz (1939, p. 210), Collenette (1991, p. 90), Verdc. (1991, p. 67), Wood (1997, p. 238).

Basionym : Heliophytum longifl orum A. DC. in DC. (1845, p. 555).

Type : Arabia: Saudi Arabi; Djebel Sidr [Mt Sedder], inter rupes montis Sedder Arabiae felicism 29 Feb 1836, Schimper 842 (holotype: G-DC, GH00097510!, isotype: BM).

Taxonomic synonym : H. gracile R. Br. (1814, p. 62) [Nom. nud.].

Two varieties of H. longifl orum can be recognized: 1 Leaves ovate, 0.5 – 1.5 cm wide; infl orescence 10.5 – 23.0

cm long, slightly lax; corolla constricted above the base … .... … … … … . … . … … . … …………… var. longifl orum – Leaves linear-lanceolate, 0.2 – 0.5 cm wide; infl orescence 5.0 – 10.0 cm long; more dense, corolla not constricted … … .......................................................... var. stenophyllum

Description Perennial herb, 50 – 60 cm high, woody at the base, densely covered with 2-branched unicellular hairs (T-shaped). Stem � terete, branched; branches erect to ascending. Leaves ovate, 1.0 – 6.0 � 0.1 – 3.5 cm; apex acute; base cuneate; margin entire; petiole 0.1 – 2.0 cm. Infl orescence lax to slightly dense, (2.0 – )10.0 – 15.0 cm, of 22 – 77 fl owers in 1-rank; fl owers ebracteate, sessile. Calyx 5-lobed; lobes free almost to the base, equal, oblong to lanceolate-linear, 0.5 – 1.5 � 0.2 – 0.5 mm, hairy outside, glabrous inside. Corolla white, 3.0 – 6.0 mm, hairy outside, glabrous inside; tube 2.0 – 4.0 mm; lobes triangular, 1.0 – 1.5( – 2.0) mm. Stamens inserted 1.0 – 2.5 mm from the base; anthers lanceolate or lanceolate-oblong, 1.0 – 2.5 mm, obtuse apex at; fi lament ca 0.1 mm. Ovary subglobose, glabrous; style 0.5 – 1.5 mm, glabrous; stigma elongate conical, 0.5 – 1.0 mm, apex shortly 2- or 4-fi d, glabrous, shorter than style. Fruit of 4 nutlets;

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Distribution Egypt; Arabia; Pakistan; India; tropical Africa; south Africa; Madagascar and Mascarene Islands. Yemen: Taiz, Sana’a, Tihama, Lahj and Socotra.

Specimens examined Yemen. El Naggar and Hamood s.n., Taiz, 31 May 2012; Hamood s.n., Tor El-Baha, 9 Nov 2009; El Naggar s.n., El-Hoban, Apr 2009; El Naggar s.n., Habil Al-Salman, Taiz, Oct 2008; El Naggar s.n., El-Hoban, Apr 2008; El Naggar s.n., Taiz, Oct 2006; El Naggar s.n., Wadi El-Enabi, Ibb, Oct 2005.

Discussion

In spite of its distinct characters, taxonomically, Heliotropium is considered a diffi cult genus in the fl ora of Yemen, and it has not got proper attention. In the classical works, the taxonomy of Heliotropium in Yemen was poorly investigated under the wide-scoped fl oristic studies of the Arabian Peninsula (Forssk å l 1775, Defl ers 1889). Perhaps, the most comprehensive fl oristic study of Yemen is the one done by Wood (1997). However, it lacks synonyms as well as type citations. Many unclear matters concerning the recogni-tion of Heliotropium taxa in Yemen were still debateble. For example, there have been no clear delimitation of H. bacciferum , H. ramosissimum and H. pterocarpum ; some authors such as Akhani and F ö rther (1994) and F ö rther (1998) preferred to treat H. bacciferum and H. ramosissimum as a species complex under the name of H. bacciferum Forssk . s.l., here, the two taxa are distin-guished and H. ramosissimum is treated as a valid species. Heliotropium undulatum was mentioned as a synonym of H. ramosissimum by Wood (1997), but is treated here as a synonym of H. bacciferum . On the other hand, Wood (1997) stated that the type of H. bacciferum described by Forssk å l from Luhayyah, seemed to be H. pterocar-pum , and consequently he excluded H. bacciferum from the fl ora of Yemen, here, we recognize that type to be H. bacciferum and is fairly distinct from H. pterocarpum . Another case is in the taxonomy of H. bottae , which was described by Wood (1997) as having 4 nutlets; the speci-men seems to be misidentifi ed, because that taxon has only two nutlets and here that taxon is treated under the name H. abyssinicum . Th ere is another plant in Somalia and tropical Africa that is morphologically very close to H. abyssinicum; Th ulin (2006) treated these as one species under the name H. steudneri Vatke, however, this point still need to be clarifi ed by examination of Somali and African specimens.

In recent few years, some check-lists claimed to comprise all the plant taxa in the fl ora of Yemen. However, these lists still need critical taxonomic revision. For example, in the list by Al-Khulaidi (2013), the number of species of Heliotropium L. in Yemen (including Socotra) is as high as 44 (and only 5 of them are endemic to Socotra). Th at number is clearly exaggerated, and is caused by misuse of synonyms.

nutlets ovoid, (1.5 – ) 2.0 – 3.0 � 1.5 – 2.0 mm, with ridge-like margin, glabrous, reticulate-rugose; margin rugose to aculeate.

Distribution Northeast tropical Africa: Djibouti, Eritrea, Sudan and Somalia; tropical Africa: Kenya, Uganda and Tanzania; the Arabian Peninsula: Saudi Arabia (Asir and Najran). Yemen: Taiz, Lahj, Tihama, Abyen and Hadhramaout.

Specimens examined Heliotropium longifl orum var. longifl orum : Yemen. El Naggar and Hamood s.n., Taiz, 31 May 2012; El Naggar and Hamood s.n., Tor El-Baha, Lahj, May 2012; El Naggar s.n., Habil Al-Salman, Taiz, Oct 2008; El Naggar s.n., Habil Al-Salman, Taiz, Apr 2005.

Heliotropium longifl orum var. stenophylum : Yemen. El Nag-gar and Hamood s.n., Hida, 27 May 2012; El Naggar and Hamood s.n., Wadi Al-Eshsh; May 2012; El Naggar and Hamood s.n., Sana’a University ground, 25 May 2012; Hamood s.n., Tor El-Baha, 2012; El Naggar s.n., Taiz, 2007.

10. Heliotropium zeylanicum (Burm. f.) Lam. (1789, p. 94) (Fig. 2h)

Literature : Blatter (1916, p. 255), Blatter (1922, p. 313), Schwartz (1939, p. 204), Collenette (1991, p. 92), Verdc. (1991, p. 56), Wood (1997, p. 239), El-Hadidy and Boulos (2000, p. 272), Th ulin (2006, p. 46).

Basionym : H. curassavicum L. var. zeylanicum Burm.f. (1768, p. 41, t. 16/2).

Type : south India: Madras; Tutikorin, Garcin s.n. (holotype: G-BURM).

Taxonomic synonyms : Tournefortia subulata Hochst. ex A. DC., in DC. (1845, p. 528). – Heliotropium subulatum (A. DC.) Vatke (1882, p. 316).

Description Perennial herb, 30 – 60 cm high, woody at the base. Stem terete, branched; branches erect. Leaves lanceolate to lin-ear, 0.8 – 10.0 � 0.2 – 2.5 cm; apex acute; base attenuate; margin entire; petiole (0.1 – )0.3 – 1.5 cm. Infl orescence lax, (5.0 – )10.0 – 23.0 cm, of 11 – 34 fl owers in 1-rank; fl owers ebracteate, sessile. Calyx 5-lobed; lobes free almost to the base, equal, ovate to narrowly elliptic, 1.0 – 3.0 mm � 0.5 – 1.0 mm, hairy outside and in the upper part inside. Corolla yellow to yellowish green, 5.0 – 7.0 mm, hairy outside, gla-brous inside; tube 3.0 – 4.0 mm; lobes ovate, 2.0 – 3.5 mm, with small intercalary teeth. Stamens inserted 1.5 – 2.5 mm from the base; anthers oblong-lanceolate, 1.0 – 1.5 mm, apex bidentate; fi lament indistinct. Ovary globose, glabrous; style 0.7 – 1.5 mm, glabrous; stigma elongate-conical, 1.0 – 1.7 mm, 2-lobed at apex, hairy throughout and with apical tufts, longer than or equaling style. Fruit of 4 nutlets; nutlets ovoid, 1.5 – 2.0 � 1.0 – 1.5 mm, glabrous, rugose.

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Nomenclature suggestions

Th e name H. abyssinicum is found to have priority over H. bottae . As varietal epithets, strigosum and bervifolium seem to have priority for the two varieties of H. strigossum (instead of var. bicolor and var. cordofanum used by some authors). A full list of synonyms for taxa of Heliotropium L. can be found in F ö rther (1998).

Many authors have stressed the paramount taxonomic importance of reproductive characters in the taxonomy of Heliotropium , among them Brown (1810), De Candolle (1845), Bunge (1869), Boissier (1875), Clarke (1885), G ü rke (1893), Johnston (1928), Riedl (1967) and F ö rther (1998). Th e following is a list of the most important morphological characters for distinguishing species of the genus in the fl ora of southern Yemen:

1) Calyx: shape and size of calyx-lobes have proved to be of taxonomic importance. H. strigosum , H. rarifl orum , H. ovali-folium and H. pterocarpum possess unequal calyx lobes; while the other species possess equal ones (Fig. 3). Th e shape of the calyx lobes varies from ovate to lanceolate-oblong/ -linear, or narrowly elliptic, and the lobes varies in size, 0.5 – 4.5 � 0.2 – 1.5 mm. 2) Corolla: colour, length, distribution of hairs, shape and size of lobes, as well as the presence of intercalary teeth at the sinus, proved to be valuable. Flowers of H. zeylanicum are completely yellow, while the rest of the species possess white fl owers. With respect to length, two categories can be recognized: 1) small-fl owered species (2.0 – 5.0 mm long), 2) large-fl owered species (5.0 – 9.0 mm long) . Heliotropium europaeum , H. strigosum , H. rarifl orum , H. ovalifolium , H. bacciferum and H. ramosissimum belong to the fi rst cat-egory; while H. abyssinicum , H. pterocarpum , H. longifl orum and H. zeylanicum belong to the second (Fig. 4). Th e inside of the corolla is glabrous in most species, but hairy in three species: H. strigosum , H. rarifl orum and H. ovalifolium . How-ever, these latter species may be distinguished by the distri-bution of hairs on the outside of the corolla: corolla hairy throughout (in H. rarifl orum ) vs hairy in upper part only.

H. zeylanicum is unique by the possession of caudate corolla-lobes wich are 5.0 – 7.0 ( – 9.0) mm long, and by the presence of intercalary teeth at the sinus. Th e rest of the species have acute or obtuse or retuse apex, and lengths up to 2.0 mm. 3) Androecium: shape, apex and connation while young proved to be variable characters. A bidentate apex is unique to H. zeylanicum (Fig. 5). Occasionally in Heliotropium spe-cies, the connective tissue is prolonged to form an apiculate, sterile apex. Th is apex is erect or curved, papillate (Fig. 6b) or glabrous, free or connate in young stages. Connate (Fig. 6a) and apiculate apices have been used to classify the genus into sections or subgenera (Brown 1810, Bentham and Hooker 1876, Riedl 1967, Verdcourt 1991, F ö rther 1998) as in H. strigosum, H. rarifl orum and H. ovalifolium of sect. Orthosyachys (formerly as subgenus). 4) Style: presence or absence, length and surface of style are of paramount taxonomic value. Heliotropium strigo-sum, H. bacciferum and H. ramosissimum possess glabrous styles; while papillate styles are typical for H. rarifl orum. Th e style is short (0.2 – 0.5 mm long) in H. ramosissimum , but relatively longer (0.5 – 0.7 mm) in the closely allied species H. bacciferum. 5) Stigma: shape of the stigma, length, apex, hairiness, and its relation to the style proved to be useful for distinguishing and separating certain taxa (Fig. 7). In the large-fl owered species, the stigma is elongated-conical, 0.5 – 1.7 mm long. Among these, a stigma that is hairy throughout is diagnostic for H. zeylanicum. Among the small-fl owered species, the stigma of H. rarifl orum is unique by being depressed capitate or coni-cal with entire apex; while it is short (squat-like) or elongated-conical with 2 – 4-lobed or -fi d apex in the other species. A stigma that is hairy throughout distinguishes H. strigosum ; while apical hairs separate H. rarifl orum and H. ovalifolium . 6) Fruit: on the basis of fruit characters (number, shape and surface), Heliotropium has been classifi ed into sections (Bunge 1869, F ö ther 1998), subgenera (Riedl 1967) or even into separate genera (Don 1837). Th e fruit is separated into 4 (1-seeded) nutlets at maturity, or into 2 (2-seeded) nutlets, or reduced into 1 nutlet by abortion. In this study, nutlet characters proved to be useful in recognizing certain taxa:

Figure 3. Shape of calyx in (a) H. europaeum , (b) H. strigosum , (c) H. rarifl orum , (d) H. ovalifolium , (e) H. abyssinicum , (f ) H. bacciferum , (g) H. ramosissimum , (h) H. pterocarpum , (i) H. longifl orum , (j) H. zeylanicum.

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Figure 4. Corolla of (a) H. europaeum , (b) H. strigosum , (c) H. rarifl orum , (d) H. ovalifolium , (e) H. abyssinicum , (f ) H. bacciferum , (g) H. ramosissimum , (h) H. pterocarpum , (i) H. longifl orum , (j) H. zeylanicum.

Figure 5. Anther shape of (a) H. europaeum , (b) H. strigosum , (c) H. rarifl orum , (d) H. ovalifolium , (e) H. abyssinicum , (f ) H. bacciferum , (g) H. ramosissimum , (h) H. pterocarpum , (i) H. longifl orum , (j) H. zeylanicum.

Figure 6. Androecium of H. ovalifolium . (a) LM photograph showing four anthers connate at the apex, (b) SEM micrograph of the anther apex showing clavate papillae.

a) Number and shape: most species in south Yemen possess 4 free nutlets (Fig. 8b, d, e, n). However, H. pterocarpum and H. abyssinicum have 2 (2-seeded) nutlets (Fig. 8g). Heliotropium pterocarpum (sect. Pterotropium ) is unique by the presence of narrow to broad lateral wings and with a deep notch at apex and base of the nutlets (Fig. 8m); while nutlets of H. abyssinicum (sect. Pseudocoelomea ) lack the lateral wings and has only a shallow notch at apex and base (Fig. 8h). b) Surface: hairiness, presence or absence of ventral cavities and sculpture are regarded as important characters in distinguishing certain taxa. Th e nutlets are glabrous in

H. pterocarpum, H. longifl orum and H. zeylanicum , while hairy in H. strigosum , H. rarifl orum , H. ovalifolium and H. abyssini-cum . In two species ( H. bacciferum and H. ramosissimum ), the nutlets are hairy or glabrous. Nutlets with a shallow groove at the middle from apex to base are found in H. abyssinicum (Fig. 8h). Heliotropium strigosum (Fig. 8c), H. rarifl orum and H. ovalifolium (Fig. 8f ) are uniquely possessing cavities (pits) on the ventral surface of the nutlets. Th ese three species belong to the section Orthostachys as defi ned by this character (John-ston 1928, Frohlich 1978). Diane et al . (2003) recognized this character in some other taxa belonging to the same section.

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Figure 7. Shape of gynoecium of (a) H. europaeum , (b) H. strigosum , (c) H. rarifl orum , (d) H. ovalifolium , (e) H. abyssinicum , (f ) H. bacciferum , (g) H. ramosissimum , (h) H. pterocarpum , (i) H. longifl orum , (j) H. zeylanicum .

Figure 8. SEM micrographs of fruit/nutlet of (a) H. europaeum , (b) – (c) H. strigosum var. strigosum , (d) H. rarifl orum , (e) – (f ) H. ovalifolium , (g) – (h) H. abyssinicum , (i) – (j) H. bacciferum , (k) – (l) H. ramosissimum , (m) H. pterocarpum , (n) – (o) H. longifl orum , (p) – (q) H. zeylanicum .

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