112. LOBELIA TUPA Campanulaceae

Victoria Matthews.

The genus Lobelia contains about 370 species which occur mainly in the tropics and sub-tropics although a small number is present in the temperate zones. The highest concentration of species is found in the Old World, especially in Africa. Only some 25-30 species are cultivated, one of the best known being L. erinus L. and its cultivars, which has, since Victorian times, been used as an edging plant in formal bedding displays, and as its trailing cultivar ‘Pendula’ is popular for growing in hanging baskets. The herbaceous perennials L. cardinalis L., with scarlet flowers, and L. siphilitica L., with flowers of violet-blue, are useful and attractive additions to the herbaceous border or bog garden. A fairly recent introduction is the creeping L. lindblomii Mildbr., an alpine from East Africa, which is suitable for the rock garden, or alpine house in cooler areas.

Also on the mountains of East Africa are found some of the strangest members of the genus, the pachycaul tree-lobelias, some of which can grow to 10 m in height.

The genus was divided into three subgenera by Wimmer in 1948. Subgen. Tupa (G. Don) Wimmer - of which L. tupa is the type species - contains tall, robust herbs or shrubs and the large flowers usually have a one-lipped corolla. Subgen. Lobelia (syn. subgen. Lagotis Wimmer) differs in containing low herbs which are often annual, and whose corollas are distinctly two-lipped with unequal lobes. In subgen. Mezleria (Presl) Wimmer, the species are small, prostrate or ascending herbs, and the small flowers have one-lipped or indistinctly two-lipped corollas with equal lobes.

Lobelia tupa was first introduced into Britain in 1824 and was figured in Curtis’s Botanical Magazine in 1825. The drawing by John Curtis (t.2550) was made from a plant which had been raised from seed sent from Chile, and grown in Mr Brooke’s Ball’s Pond Nursery in London. The present drawing is of a plant grown at the Royal Botanic Gardens, Kew, grown from seed collected near Valdivia in Chile by S. Henchie and A. Kirkham (no. 88) in March 1985.

In its native Chile, L. tupa is a plant found on hillsides and in grassy places, often near the coast. There are reports of it growing in northern Chile and southern Peru, but these are unsubstantiated and seem unlikely as the climate is so much drier than that of central

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Chile. Linnaeus in the second edition of Species Plantarum states that the plant comes from Peru, despite citing the work of Feuillte who says that he found it in Chile at a latitude of 37”s. There is no extant type specimen.

The red flowers of L. tupa are ideally shaped for humming-bird pollination and produce copious amounts of nectar to reward the visitors which are attracted to the bright colour. ‘The anthers dehisce introrsely before the stigma emerges, so that the pollen is pushed out of the hole at the top of the ring of anthers by the stigma whose lobes are adpressed together; this situation occurs also in the Compositae. The stigma-lobes then separate and the receptive surfaces are ready to receive pollen from another flower.

Lobelia tupa is known to have psychoactive properties and may possibly contain hallucinogens, although this has not been proved (Emboden, 1972; Schultes, 1980 and 198 1 ) . The Mapuche Indians of Chile smoke the leaves to produce an inebriating effect; their name for the plant is tupa or Lrupn, and in Spanish it is known as labaco del diablo - devil’s tobacco. The juice expressed from the leaves is used by peasants in Chile to relieve the pain of toothache. Analysis of the leaves has shown that they contain the alkaloids lobeline (a respiratory stimulant), including its diketo- and dihydroxy- derivations, lobelanidine and nor-lobelanidine.

That the latex of the plant can have an adverse affect has been demonstrated recently. In late autumn 1987, James Compton of the Chelsea Physic Garden in London was cutting down the dead stems. ofL . tupa, to tidy the plant before the onset ofwinter. He noticed that the bases of the stems contained large quantities of latex which had become powdery and which dispersed into the air when the stems were cut. Mr Compton not only began to feel extremely unwell but fell to the ground and was unable to get up for some 10-15 minutes. A colleague who came to his aid also began to feel unwell. I t would appear that there is some constituent of L. tupa which exerts an extremely unpleasant influence; indeed as far back as 1714, Feuillte noted that the smell of the plant produced ‘cruel vomiting’. Gardeners should not be dissuaded from growing this spectacular plant, but should, nevertheless, exercise care when handling the cut stems.

Three varieties of L. tupn have been described, in addition to the type variety, viz. var. montana (Phil.) Reiche, var. bicalcarata (A. Zahlb.) Wimmer and var. pauonii Wimmer. All of them differ

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Plate 112

Lobelia tupa JOANNA LANGHORNE

Lobeliatupa. A, bract, x I ; B, flower, with attached bract, x 1; C, half-flower, X 14; D, corolla, opened out, x If; E:, calyx, x 14; F, top ofstaminal tube opened out, x 3; G , style and stigma, x 3; H, part ofovary with ovules, x 3.

from var. h p a in having leaves which are broadly decurrent with the wings running so far down the stem that they almost meet the next leaf below. I n addition, var. montana possesses broadly lanceolate bracts which are shorter than the pedicels, var. bicalcarata has bracts with two pointed, basal auricles, and var.pavonii has bracts which are decurrent. T h e plant figured on Plate 112 is var. tufa.

CULTIVATION. Seed usually germinates in about 10 days; it is small and can be sown without being covered. Plant; grown from seed sown in spring will usually produce some flowers in the first year, but

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the plant will generally reach its full size in the second year. A warm, sunny position in well-drained soil suits it best, with plenty of moisture in the growing season. I t grows best in southern Britain or on the mild west coasts of Scotland and Ireland; in cooler areas or on heavy soil, protection during the winter is advisable, using a mulch of bracken, straw or peat or even placing a cloche over the dormant plants. Growing it at the foot of a south-facing wall will provide additional protection. It is not commonly seen in gardens which is a pity as the handsome foliage and oddly shaped flowers always attract attention.

Although in its native Chile it is an evergreen perennial, when grown in Britain it behaves as a herbaceous perennial, the stems dying back to ground level at the onset ofwinter. It may be necessary to stake the tall stems, especially if the plant is grown in a position subjected to occasional wind. Lancaster ( 1987) suggests brushwood as a support, inserted around the crown early in the year so that the stems grow through in the spring.

Propagation is by seed or cuttings. In Britain, L. tupa flowers betweenJune and September. It was given an Award ofMerit by the Royal Horticultural Society in 1927.

DESCRIPTION. Erect perennial with tomentose, angled stems up to 3 m tall; plant containing creamy white latex. Leave.r light yellowish green, sessile, broadly lanceolate to ovate-oblong, 10-23(-30) cm long, 2.5-8.5(-10) cm wide, the apex acute to acuminate, the base decurrent, margin finely denticulate, both surfaces densely white-tomentose. Inflorescence a simple, many-flowered raceme bearing resupinate flowers, the axis often reddish purple. Bracts lanceolate to ovate, often with marginal teeth 0.5 mm long, shorter than or equal in length to the pedicels, occasionally slightly longer. Pedicels tomentose, up to 4.5cm long at anthesis, reddish purple. Calyx reddish purple, tomentose, l0-veined, the tube semi-globose, 8-10(-12) cm in diameter, the lobes 5, triangular-lanceolate, 4-7 mm long. Corolla scarlet to crimson-red, downy, 3-5 cm long, curved upjvards and then reflexed, l-lipped, the 2 lateral lobes 12-20 mm long, the 3 middle lobes 6-15 mm long, each lobe with a minute terminal hook by which the tips hold together. Stamens coherent into a tube which emerges through a slit in the back ofthe corolla; filaments red or purplish red, 22-26 mm long, minutely downy, upcurved; anthers greyish or bluish, 6-7 mm long, white-hairy, the 2 lower ones white-bearded. Ovary 2-locular with parietal placentation. SQle pale yellow, slender, a t first included within the stamina1 tube, later emerging through the top, bearing a broad ring of hairs below the stigma. Stigma 2-lobed, the lobes adpressed to one another a t first but separating after the stigma emerges through the ring of anthers. Fruil a subglobose capsule up to 14 mm long.

DISTRIBUTION. Central Chile; sea-level to 600 m.

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Lobelia tupa L., Sp. P1. (ed.2) 1318 (1763); Curtis's Bot. Mag. t.2550 (1825); Edwards' Bot. Reg. t.1612 (1833); Reiche, F1. Chile 5: 59 (1910). Type: Chile, 37"S, in FeuillCe, J. Obs. 2: t.29 (1714) (lectotype designated here). L. trapa L., Sp. P1. 929 ( 1753) - typographical error. Tupa feuillei G. Don, Gen. Syst. Gard. Bot. 3: 700 (1834); Gay, Hist. Chile

Rapuntium tupa (L.) C. Presl, Prodr. Lobel. 28 ( 1836). Tupa feuillei var. rnacrophylla Vatke in Linnaea 38: 726 ( 1 874). Dortmannia tupa (L.) 0. Kuntze, Revis. Gen. P1. 2: 972 (1891).

Bot. 4: 328 (1849).

ACKNOWLEDGMENTS. I am grateful to Brian Halliwell who provided information on cultivation, and also to Sabina Knees and Nigel P.Taylor, whose knowledge of the species both in the wild and in cultivation has added considerably to this article.

REFERENCES

Emboden, W. (1972). Narcotic Plants 76. London. Lancaster, R. (1987). Garden Plants f o r Connoisseurs 146-148. London and

Schultes, R.E. (1981). Lobelia tupa, in Iconography of New World Sydney.

hallucinogens. Arnoldia 41: 122-123. and Hofinann, A. (1980). Plants of the Gods 78-79. London.

Wimmer, F.E. ( 1948). Vorarbeiten zur Monographie der Campanulaceae-

( 1953). Das Pflanzenreich (IV.276b) Campanulaceae-Lobelioideae

(1968). Idem. Supplement. .

Lobelioideae: 11. Trib. Lobelieae. Ann. Nat. Mus. Wien 56: 317-374.

- Vol. 2.

TWO RECENTLY INTRODUCED SPECIES OF PLEIONE FROM CHINA

Phillip Cribb

The centre of diversity of the genus Pleione lies in the Chinese province of Yunnan. Tucked away in the remote south-west of that vast country and bordered by Burma to the west and the blighted countries of Vietnam and Laos to the south, Yunnan has been a mecca for plant collectors over the past 100 years. Its high mountains and deep gorges have provided a feast of garden-worthy plants that collectors such as P6re Delavay, George Forrest, Frank Kingdon Ward and Joseph Rock have introduced into cultivation. Their

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