43. WEBEROCEREUS TONDUZII Cactaceae

David Hunt

Weberocereus tonduzii is one of many night-flowering cacti from the forests of tropical America. Some have extremely large and fleeting white blooms and are all popularly known as ‘Queen of the Night’ or, in Spanish, ‘Reina de la Noche’, although they actually belong to several different genera, including Selenicereus, Hylocereus, Epiphyl- lum and Nyctocereus. In comparison with these, the flowers of Weberocereus are insignificant, though they sometimes make up in quantity for what they lack in size. The buds secrete aromatic nectar from the scales on the tube, and the flowers have a faintly musty smell, like most of their grander sisters.

Weberocereus tonduzii is endemic to Costa Rica, whence it has been reported a number of times on the western slopes of the Cordillera de Talamanca. Judging from remarks by C . Horich, quoted by Kimnach (1958), the species must have been much reduced, if not endangered, by deforestation for lumber since Adolphe Tonduz first collected it in 1898.

The classification of W. tonduzii is not yet resolved. It was originally described in the hold-all genus Cereus, nowadays restricted by nearly a11 authors to a mainly South American group of tree-like species with flowers devoid of spines or scales. The American monographers Britton & Rose made Tonduz’s plant the type species of one of their numerous segregate genera, Werckleo- cereus, but the differences from allied genera in the scheme were trivial at the outset and have broken down with the subsequent discovery of intermediate species. A less radical solution was suggested by Kimnach & Hutchison (Cact. J. Amer. 29:26-28. 1957), involving the merger of Werckleocereus and Eccremocactus B. & R. with Weberocereus B. & R., but the name-changes implied were never made. It is, however, a solution which cannot be improved on at present, and so is adopted here, and the necessary new combinations proposed on page 341.

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The three species hitherto referred to Werckleocereus are differenti- ated as follows:

W. glaber ?-angled, somcwhat glaucous, spines 2-4, 1-3 mm

10-12 cm spiny, not dccurren t

oblanccolatc

elobosc ycllow

stems

flowcrs Icngth podaria

W. imitans flat, deeply lobed, usually spineless

7cm spiny at lowcr areoles only, dccurrcn t ovate-lanceolatc

oblone, rcd

inncr segments

fruit

CV. kvduzii 3-angled, green, usually spinclcss

up to 8 cni spiny, not decurrerit

oblong

globosc, ycllow

C L ~ I . I ~ I \ . . \ I . I ~ N . 131. tonduzii needs much the same treatment as other coarse-stemmed forest cacti, preferring a compost rich in organic matter and a warm and humid, but well-ventilated, atmosphere. Ample watering, periodic liquid-feeding and protec- tion from full sun are needed in the summer months, but watering should be only sparing in the winter resting season, when a minimum temperature of 10°C (50°F) will be adequate. The stems need the support of canes or trellis. Propagation is by cuttings, or if more than one clone is available and precautions against crossing with allied specied are taken, by seed.

DI:S(:KIPTION. Slem climbing, creeping or pcndulous, segmcntcd, the scgmcnts 3 - or rarely 4-anglcd or wingcd, 10-40 X 2-3(-5) cm, light green, rooting aerially; areoles 1-3 cm apart, raiscd on low crcnulations, with short dark wool, usually spinclcss or with 1-2 brownish spincs up to 2mm. Flozeers arising ticar the apex of segments, somctimcs numcrous, hut 1 pcr arcolc, funnelshapcd, 6-8 X 4-5 cm; receptacle-tubc 3.5-6 cm X 10-14 mm at middle, somewhat flared abovc, grccn to brownish, with numerous (30-40) areoles on low, non-decurrent podaria, with short dark wool and 5- 18 bristly brown spines up to 6(-9) mm. Oulerperianllz-segnzenls lincar, fleshy and somewhat concave, pale greenish or brownish yellow. Inner perianth-segmenls oblong, obtuse and crosc-dentate at apex, crcamy whitc. Stamens very numerous, inserted in a ring (throat circlc) at the mouth of thc tube and in a zone abovc thc ncctary-chamber, shortly cxsertcd with thc style. SLvle creamy whitc, with 9-12 erect papillatc stigma-lobes. Fruil subglobose, c. 4 cm diam., pulpy, ycllow when ripe, with numerous spiny arcolcs, and crowned with thc withered remains of the flowcr. Seeds obovatc, 1.5-2.25 X 1-1.5 mm, glossy brownish black, with conspicuous hilum.

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Plate 43

CHRISTABEL. KING

DISI R I H L ~ ~ l ’ l O N . Costa Rica, provinccs of Lini6n and Sail Jos6 a t 1500-1800 m altitude.

Weberocereus tonduzii (F.A.C. \Vchcr) 1I.R. Hunt, conib. nozi. Cereus /ondu;ii F.A.C. Wcbcr i n B~tll. Mus. Hist. Nat. Paris. 8: 4.59 (1902). Werckleocereus londuzii (F.A.C. Wrbcr) Britton & Rose in Contr. US. Nat.

Hrrh. 12: 432 (1909); Kimnach in Cact. Succ. .J. 30(2):35-39 (1958). ’Iypc: Costa Rica, prov. San Jos6, ncar Sta Maria dc Dcta, Copcy, 1898, Tonduz 1915 (P).

New comhinations for allicd species: Weberocereus glaber (Eictilani) I1.R. Hunt, conrb. nou. Cerrus glnber Eichlam in Monatssclir. Kakt. 20: 150 (1910). ‘Iypc:

Guatemala, ‘ncar the Pacific coast’, Eich/rrm; not statrd t o have bcwi prcscrvcd.

Il’erckleocereus glaber Britton & Rose in Addisonia 2: 13 (1917).

Weberocereus imitans (Kimnach & Hutchison) 1I.R. Hunt, comb. nov. II’erckleocereus imi/aiis Kimnacli & Hutcliison in Cact. Succ. J. Anicr. 28(5):

154 (1956). Type: Costa Rica, El General Valley, near Caiias, coll. C. H . Lankcstcr, cult. Univ. Calif.. Rot. Gardcn no. 52.1083 (UC, holo., US, iso).

Weberocereus bradei (Britton & Rosc) D.R. Hunt, conib. 11011.

Eccrenzocac/us bradei Britton & Rosr in Contr. US. Nat . Hcrh. 16: 262 (1913). Type: Costa Rica, ncar Santo Domingo (Orotina), ‘Iurruvarcs, alt. 200 m, 1905, Brade in hlacrson 21, cult. N r w York H o t . Gardcn no.24949 (flowcrcd 191 1) (NY) .

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