from the back. Petals entire, narrowly oblong-trapezoid, 6-7 mm long, 2 mm wide, included within the galea and arranged horizontally on either side of the anther, fused to the rostellum, the apex curved over the anther. Lip spreading, narrowly oblong, 6-7 mm long, subacute. Column partially erect, reflexed above. Rostellum 3-lobed, the lateral lobes erect, 3-4 mm tall, the central lobe a small fold between the lateral lobes. Anther almost horizontal, 3mm long, bearing 2 massulate pollinia each with its own viscidium. Stigma equally 3-pulvinate, sessile at the base of the rostellum.

DISTRIBUTION. South Africa: Cape Province, Riversdale Division, on the northern slopes of the Langeberg, at the edges ofstreams; altitude c. 600 m.

Disa cardinalis Linder in J. S. African Bot. 46: 213 (1980), F1. P1. Afr. 46(3), pl. 1826 (1981), Contrib. Bol. Herb. 9: 290-291 (1981) and in Stewart et al., Wild Orchids of Southern Africa 138 (1982). Type: South Africa, Cape, Riversdale, Garcias Pass, 15 December 1977, Linder 17 16 (holotype BOL; isotypes K, PRE).

95. PINELLIA TRIPARTITA Araceae

Peter Boyce

Pinellia is a small genus of hardy, tuberous rooted Aroids from China and Japan which, although not as flamboyant as the related Arisaema, possesses a subtle charm all of its own. At present four of the seven recognized species are in cultivation here in Britain, and of these P. tripartita is perhaps the least well known.

Unusually, the nomenclature of the genus is quite straightforward and thus one does not have to wade through the proverbial mine- field of synonyms that so often burden members of this family. Pinellia was described by the Italian botanist Tenore in 1839 for the only species known to him, P. tuberifera, now called P. ternata. Material of P. tripartita was sent to Blume who considered that, along with P. ternata, it represented a new genus, and he proposed the name Atherurus in 1835. The description of A. tripartita states that the material came from China by way of Japan, however this is un- doubtably an error as P. tripartita is restricted to Japan. Schott in his 1856 treatment of the Araceae considered that there were insufficient grounds for maintaining Blume’s genus and placed A . tripartita in Pinellia. Nicholson (1967) pointed out that Atherurus (1835) had priority over Pinellia (1839), but the latter was subsequently

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PIate 95

Pinellia tripartita MARK FOTHERGILL

proposed for conservation and is now listed as such in the Inter- national Code (1983). Only one other alteration has occurred since then, that being the transfer of P. tripartita to Arisaema by Engler in 1879, a move that was not widely accepted, and was in fact reversed by Engler himself in his subsequent treatment of the family in 1920.

Whilst Blume’s placing of this species in a separate genus could appear to be a reasonable decision, particularly if the scarcity of oriental material in 1837 is taken in to account, Engler’s decision to place the plant in Arisaema is something of a puzzle since the two genera are really very distinct. In Pinellia the pistillate flower zone is fused to the spathe-tube interior for the whole ofits length, the spadix becoming free a few millimetres below the staminate zone; in Arisaema the spadix is free. In addition, in Pinellia the spadix is always bisexual, whereas in Arisaema it is very often unisexual, and the male and female inflorescence may be markedly different in overall morphology.

Pinellia is a homogeneous genus, all t‘he species displaying strong floral similarity, although vegetatively they are very diverse. Two foliage forms are to be found, having either entire or lobed leaves. Pinellia tripartita belongs to the latter group and is closely allied to P. ternata. The spathes of P. tripartita, whilst not showy, are amongst the largest in the genus; borne at approximately leaf height they are made particularly conspicuous by the long, erect, spadix appendix that overtops the foliage by several centimetres. The purpose of this is not entirely clear, but my observations of plants in cultivation suggest that it acts as a scent flag. The rather incon- spicuous nature of the spathes, particularly when the woodland habitat of the plant is taken into account, means that they must have a method of advertising their presence. Since all the members of the genus are to a greater or lesser degree scented, this is apparently the method employed to disperse the scent and ensure that adequate pollinators are attracted. Whilst on the subject of scent it is worth noting that the genus possesses a range of odours reminiscent of various fruits, apple and citrus being two of the most prominent. Thus they can provide a welcome addition to the cool greenhouse, and a pleasant alternative to the more potent smells associated with the Araceae.

A form with a purple interior to the spathe, P. tripartita f. atro- purpurea (Makino) Ohwi, was described in FL. Japan (English edition) 225-264 (1965). Makino (Bat. Mag. ( T o k y o ) 15: 135, 1901) stated

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that it is rare and that he had only seen the type specimen. CULTIVATION. The species are easily cultivated, and so far they

have all proved to be hardy in Britain. O n the whole they require a cool and shaded regime. I have found that for pot culture a shallow pan is best, using a compost of two parts rough peat, one part bark chips and one part coarse grit. A general purpose fertilizer such as Vitax Q4 can be incorporated at the rate of 30 grammes per 9 litre bucket, or alternatively a liquid feed can be given at every other watering throughout the growing season. Under glass, care must be taken to ensure that the plants are adequately shaded since the relatively thin-textured leaves scorch very easily. Additionally, lack of shading will dry out the atmosphere and allow pests such as red spider to gain a hold, which can seriously disfigure the foliage. When dormant the plants must not be fully dried out since the relatively small tubers can shrivel badly and may rot once watered again. Outdoors the best position is a moist, shaded bed with plenty of leaf-

Pinellia tripartita. A, sub-longitudinal section of inflorescence, x 2; B, pistillate flower, x 10; C , habit, X + .

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litter a n d grit incorporated if the soil is heavy a n d badly drained. T h e newly emerged shoots should be protected, as slugs seem particularly partial to these as a n hors d’oeuue before moving on to the Arisaema species for the main course!

DESCRIPTION. Perennial herb up to 35cm tall with a globose tuber up to 3 cm across, densely clothed with mid-brown fibrous sheaths, these de- composing into individual fibres with age. Leaves 1 or 2, rarely up to 5; petiolate, petioles up to 30cm long and 4mm thick, terete, with an inconspicuous 1-2 cm long, pale green, basal sheath, new leaves and inflorescences emerging from the previous leaf-sheath; lamina deeply 3- lobed, the lobes free or not quite divided to the base, pale lime green above and below, broadly ovate-elliptic, the base obliquely cuneate, the apex acuminate, margins smooth, undulate. Inflorescence subequal to just over- topping the foliage. Peduncle up to 27 cm long and 3 mm thick, pale green, terete. Spathe-tube 2.5 cm long, up to 5 mm wide across the middle, oblong, slightly ventricose below, constricted above, a fleshy septum present internally at the point of the constriction, dividing the spathe into 2 chambers, margins free for their whole length, exterior pale green, slightly glaucous, interior whitish green. Spathe-limb up to 4.5 cm long, 8 mm wide across the middle of the cylindrical lower portion, the upper part elliptic, flaring to form the opening, the apex subacute, with a minute tooth, exterior rather glossy pale olive green, interior densely papillose, whitish green. Spadix up to 16cm long, the appendix c. 14cm long, sessile, flagel- liform, slightly swollen basally above the staminate flowers, glossy pale green, smelling strongly of fermenting apples. StaminateJowers arranged in a cylindrical zone 7 mm long, 3 mm wide, the individual flowers consisting of 2 anthers fused together, dehiscing by apical slits; pollen very pale cream. Pistillateflowers arranged in a band 7 mm long, 3 mm wide, fused to the back of the spathe-tube wall, the individual flowers consisting of a single naked pistil; ovary c. 2 mm high, 0.5 mm wide, glossy pale green; stigma stalked, capitate, white. Fruiting head consisting of a 4-5 cm long, half-cylindrical cluster of pale green, later orange-red, ovoid berries, the lower half enclosed by the persistent spathe-tube, individual berries 5-10 mm across, containing 1 or 2 pale brown, ovate seeds.

DISTRIBUTION. Southern Japan; Kyushu, Shikoku, S. Honshu.

Pinellia tripartita (Blume) Schott, Syn. Aroid. 5 (1856); Engler, Pflanzenr. 73 (iv. 23F): 222 (1920); Satake et al., Wild Flowers ofJapan’ 1: 28, pl. 11 1 (1981); Satake et al., Wild Flowers ofJapan 1: 60, pl. 11 1 (1985). Type ‘from China, via Japan’ (L?). Atherurus tripartitus Blume, Rumphia 1 : 136, t.3 1 ( 1835); Nicholson in Taxon

16: 515 (1967); Voss et al., International Code of Botanical Nomenclature 32 1 ( 1983).

Arisaema tripartitum (Blume) Engler in A. & C. DC., Monog. Phanerog. 2: 538 (1879). Type: Japan ‘growing by roadsides, shady woods etc. Nagasake’, R. Oldham 819 (K!).

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