Cydista lilacina A.H.Gentry

Authority

Maguire, Bassett. 1978. The botany of the Guayana Highland--part X. Mem. New York Bot. Gard. 29: 1-288.

Family

Bignoniaceae

Scientific Name

Cydista lilacina A.H.Gentry

Description

Latin Diagnosis - Frutex scandens ramuli teretes, pseudostipulis inconspicuis, sine consociebus glandularum in nodis inter petioles; folium bifoliolatum, interdum cirrho simplici. foliohs ovatis, acutis, basi truncatis vel subcordatis, fere glabris; inflorescentia anguste paniculata, lepidota; calyx cupulatus, 5-denticulatus, lepidotus; corolla lavendula, tubulo-infundibuliformis, extus glabra; stamina didynama, thecis divaricatis; ovarium oblongum, dense lepidotum; discus deficiens; capsula oblonga, in longitudinem rugata, parum lepidota; semina bialata, omnina brunneola.

Species Description - Vine, the branchlets terete, finely striate, drying blackish, very sparsely lepidote, without interpetiolar glandular fields, pseudostipules thick-foliaceous on young branchlets, otherwise minute and shortly conical or absent. Leaves 2-foliolate, sometimes with a simple tendril, the leaflets ovate, acute, truncate to subcordate at base, 5-19 cm long, 2.8-12.5 cm wide, chartaceous, glabrous throughout except for scattered minute lepidote scales, with scattered plateshaped glands along midvein below, these concentrated into glandular fields in axils of basal secondary nerves below, drying dark green to blackish above and below; petiolules 0.5-4 cm long, petiole 1-4 cm long, slightly lepidote. Inflorescence a terminal panicle with a well-developed rachis and mostly 2-3-flowered lateral branches, the basal lateral branches sometimes dichotomously branched with each dichotomy 2-3-flowered, the rachis and pedicels more or less lepidote, otherwise glabrous, bracts and bracteoles not evident. Flowers with the calyx cupular, shortly 5-dentate, 5-7 mm long, 5-7 mm wide, lepidote, the teeth more or less ciliate, with a few plate-shaped glands near margin; coroha lavender with a white throat, tubular-infundibuliform 4.4-5.5 cm long, 1.0-1.5 cm wide at mouth of tube, the tube 2.5-3.7 cm long, lobes 1.5-1.8 cm long, the tube glabrous outside, mostly glabrous inside, puberulous at and below level of stamen insertion, the lobes more or less glandular-lepidote and puberulous, especiahy inside; stamens didynamous, the anther thecae 3-4 mm long, divaricate, the connective blunt, the longer filaments 1.2-1.3 cm long, shorter filaments 0.8-1.0 cm long, staminode 3-4 mm long, insertion 5-6 mm above base of corolla tube; pistil 2.3-2.4 cm long, the ovary oblong, 3-4 mm long, 1.5 mm wide, densely lepidote, longitudinally grooved, the ovules distinctly but irregularly 4-seriate in each locule; disc obsolete. Capsule oblong, compressed, 14-16 cm long, 3-3.8 cm wide, drying black, sometimes splitting along the not at all raised midrib, margins rounded, surface with numerous longitudinal wrinkles, these variously anastamosing especially toward apex where two larger submarginal wrinkles are formed, inconspicuously lepidote, otherwise glabrous; seeds thin, flat, bialate, 1.5-2.1 cm long, 3.5-5.8 cm wide, the body rather broad, the hilum 1-2 mm wide, 10-14 mm long, ca 1 mm from seed margin, the wings irregular, rather narrow, brownish, indistinctly demarcated from body of seed.

Discussion

Type. VENEZUELA. Bolivar: Tumeremo to Anacoco (north side of Cuyuni River) 56-57 km from Guyana fronder at Anacoco, 140-200 m alt, tropical moist forest and roadside second growth; vine, flowers lavender with white throat, fragrant, calyx brownish, 18 Mar 1974, A. Gentry, G. Morillo & B. de Morillo 10673 (holotype MO, isotypes MO, VEN). Cydista lilacina is an important discovery, providing links among no less than three genera: Cydista, Clytostoma, and Roentgenia. Superficially it looks very much like Clytostoma uleanum Kranzl., especially in its elongate racemosepaniculate inflorescence but also in the appearance of its leaves. That species differs in having the corolla tube lepidote and subpuberulous outside, pedicels and calyx much less (or not at all) lepidote, and especially in the characteristic glandular muricate ovary and echinate fruit of its genus. Roentgenia sordida (Bur. & K. Schum.) Sprague & Sandw. also has a rather similar inflorescence, although in that species the inflorescence is usually axillary and more often strictly racemose while the corolla tube is conspicuously glandular-lepidote outside. Cydista heterophylla Seibert has a similarly lepidote calyx and only slightly lepidote corolla tube but its inflorescence is strictly racemose and the leaves are 3-veined from the base. Variable and widespread Cydista aequinoctialis (L.) Miers, which differs from C. lilacina and the other species noted above in its more or less tetragonal branchlets, is otherwise vegetatively similar to the new species; it also differs in a smaller and corymbose-paniculate inflorescence with longer lateral branches and without a well-developed central axis; it also has the corolla tube more or less lepidote outside and a more infundibuliform calyx. Other species of Cydista have even more conspicuously tetragonal branchlets with ribbed angles. All previously known species of Cydista have 2-seriate ovules. The fruit of C. lilacina is especially interesting. In its oblong shape and wrinkled surface it is reminiscent of that of Mussatia hyacinthina (Standi.) Sandw. The only species of Cydista with a similarly oblong fruit is C. potosina (K. Schum. & Loes.) Loes. which differs in a smooth fruit surface. The apical aggregation of the fine surface wrinkles of the fruit of C. lilacina into two relatively distinct ridges gives an effect rather reminiscent of the two submarginal ridges found in C. heterophylla. This is only the fifth species of Cydista recognized by me and the first exclusively South American one. Cydista aequinoctialis occupies the entire area of distribution of the genus from Mexico and the West Indies to Amazonia. An extremely pubescent form of the species, best treated as C aequinoctialis var hirtella (Benth.) A. Gentry but often specificahy segregated, is known from Mexico to Panama. Cydista diversifolia (H.B.K.) Miers ranges from Mexico to northern Venezuela and also occurs on Cuba. Cydista potosina is restricted to northern Central America in Honduras, Guatemala, Belize and adjacent Mexico. Cydista heterophylla is distributed from southern Mexico to northern Colombia (Dugand 5034 (COL) from Adandco, Colombia is the first South American cohection) and is also to be expected in northwest Venezuela.

Distribution

Distribution. This plant has been collected in extreme western Brazil and adjacent Bolivia and southern Venezuela. VENEZUELA. Bolivar: Tumeremo to Anacoco (north side of Cuyuni River) 72 km from Guyana frontier at Anacoco, sterile vine; 18 Mar 1974, Gentry et al 10641 (MO). 31-33 km S of San Felix, N of Upata, along stream and roadside, 260 m ah, dry forest; sterhe vine, 19 Mar 1974, Gentry et al 10737 (MO, VEN). 14-25 km N of El Dorado; tall moist forest along road; liana, fruits green; 15 Mar

Venezuela South America| Bolivia South America|