DIVERSITY IN ZANONIA INDICA ( CUCURBITACEAE )

A revision of the monotypic genus Zanonia L. is presented. The only and widely distributed species Z. indica comprises two subspecies, the typical one, and the newly described subsp. orientalis W.J. de Wilde & Duyfjes. Subspecies orientalis also contains a distinct variety, var. paludosa W.J. de Wilde & Duyfjes.

Therefore, we refrain from recognizing var.pubescens, although we have not seen the exceptionally hairy, very large-fruited material from China.
during our study we found that plants from Peninsular india and sri Lanka have much larger male flowers than those from NE india, China and the whole area southeast to New Guinea.The two areas of the larger-and the smaller-flowered plants are geographically separated by a wide gap, the indian Gangetic Plain.As the difference in flower size is quite apparent, we herewith propose the status of subspecies for both groups, viz.subsp.indica for the specimens from Peninsular india and sri Lanka and subsp.orientalis for the specimens of the remaining distributional area.deviating material from peat swamp in Borneo is here newly described as a variety (var.paludosa) under subsp.orientalis.Medium-sized liana; dioecious.Probract absent.Tendrils: (simple or) 2-branched at apex.Leaves: simple, unlobed, ovate-elliptic (-narrowly elliptic), margin entire; cystoliths absent; petiole short.Flowers: small, creamy-white; buds globose; perianth rotate; sepals 3 (but see note 1), concave, valvate in bud; petals 5, free, ± fleshy, conduplicate-valvate with tips inflexed in bud; receptacle shallow.Male inflorescences: paniculate, many-flowered, pendulous; bracts small, linear, 1(-2) mm long, glabrous or hairy.Male flowers: pedicel short; disc broad, low; stamens 5, free, inserted on the disc, filaments short, anthers all 1-thecous, opening with apical transverse slit; pistillode absent.Female flowers: in (raceme-like) panicles; pedicel very short or absent; ovary clavate, imperfectly 3-locular, each locule with apically 2 pendulous ovules; styles 3, short, horizontally 2-horned, separate, inserted on slightly raised truncate apex of ovary; staminodes absent or present (see note 2).Fruits: rather large, capsular, elongate-cylindrical, claviform, with truncate apex opening by 3 inward curving apical valves.Seeds: compressed, longitudinally winged all around the seed.

ZANONIA
distribution -One species with two subspecies, from india and s China, east to New Guinea.
Notes -1.The globose calyx in bud is membranous, and closed at apex, but mostly the very apex shows 5 minute appendages proving that the calyx is morphologically 5-merous.However, at anthesis the globose bud splits into (2 or) 3 triangular ± concave sepals.The five petals are thick-fleshy and drop off easily after anthesis.

Zanonia indica L.
Habitat & Ecology -forest edges, riversides, open forest on mountain slopes; (0-)20-800 m altitude (recorded for Bhutan at 2300 m by Grierson & Long, 1991: 269).flowering and fruiting throughout the year.Notes -1.Zanonia indica subsp.orientalis is distributed over a vast area and shows considerable variation in hairiness and size of fruit.Conspicuously hairy specimens, of provenance from a wide area, induced Cogniaux (1881) to recognize a variety with hairy branches, var.pubescens.We found that hairiness usually concerns all parts of the plant, including fruits, and it is variable from (almost) glabrous to densely hairy, although subglabrous plants may still have finely hairy inflorescences and tendrils.despite that strongly hairy forms (most frequent on limestone in Central Thailand, for instance) may conspicuously differ in appearance from glabrous forms, we cannot see other than a continuous variation.
The same holds true for the size of the fruits: its length generally varies from 6-9 cm, but strikingly small fruits, c. 4 by 2(-2.5)cm seem usual in New Guinea.Very large hairy fruits, c. 10 by 4.5-5 cm, with long-winged seeds, c. 8 by 2 cm, are mentioned for s yunnan (Chen, 1995), under the variety pubescens.in var.indica of Chinese floras (Chen, 1986(Chen, , 1995) ) these dimensions are smaller.We have not seen this material and we do not know whether the large-fruited plants merit a separate status.
2. sterile material of Z. indica may much resemble sterile Alsomitra macrocarpa.The latter generally has longer petioles and a characteristic short-hairy spot in the leaf axil; also, the adhesive pads which may develop at the end of the tendril-branches are larger and more elongate, to 1.3 cm long (fig.2g).furthermore, the bark of twigs in Alsomitra is not or but finely striate (coarsely striate in Zanonia), and without or with few very small lenticels.