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Flora of the Venezuelan Guayana

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BIGNONIACEAE

12. DISTICTELLA Kuntze in T. Post & Kuntze, Lex. Gen. Phan. 182. 1903.

Lianas or shrubs, the branchlets terete, lacking interpetiolar glandular fields; pseudostipules inconspicuous, short and thick. Leaves simple to 3-foliolate; terminal leaflet sometimes replaced with a trifid tendril. Inflorescence a racemose panicle or raceme, terminal or axillary. Calyx cupular, truncate, thick, usually with large plate-shaped glands below margin; corolla white, tubular-campanulate, densely short-pubescent outside. Anthers glabrous, the thecae straight, divaricate. Ovary ovoid-oblong, puberulous; ovules 4-8-seriate in each locule; disk annular-pulvinate. Fruit a capsule, the valves flattened or strongly convex, parallel to the septum, thick and woody, smooth or slightly minutely rugose, frequently puberulous. Seeds usually thin, glabrous, with brownish wings, sometimes thicker and the wings reduced or essentially lacking.

Costa Rica, Panama, Colombia, Venezuela, Tobago, Guyana, Suriname, French Guiana, Ecuador, Peru, Brazil, Bolivia; 13 species, 9 in Venezuela, all of these in the flora area.

The Guayana Shield is the center of diversification of Distictella.

Key to the Species of Distictella

1. Leaves simple ..... 2

1. Leaves 2-foliolate ..... 3

2(1). Lower leaf surface smooth, sparsely lepidote, otherwise glabrous ..... D. laevis

2. Lower leaf surface intricately and conspicuously raised-reticulate, puberulous ..... D. monophylla

3(1). Leaves ± glabrous ..... 4

3. Leaves puberulous over the entire lower surface ..... 5

4(3). Leaflets elliptic to ovate, less than 21/2 times longer than wide; corolla white; inflorescence long, racemose-paniculate ..... D. magnoliifolia

4. Leaflets narrowly elliptic to lanceolate-elliptic, > 3 times longer than wide; corolla pale lavender; inflorescence 1- or 2-flowered ..... D. pauciflora

5(3). Petioles, petiolules, inflorescence and branchlets with trichomes ca. 1 mm long; leaflets bullate or not ..... 6

5. Vegetative parts and inflorescence minutely puberulous, the trichomes not reddish; leaflets not bullate ..... 7

6(5). Leaflets not bullate; trichomes tannish; below 500 m elevation ..... D. dasytricha

6. Leaflets bullate; trichomes reddish; above 800 m elevation ..... D. porphyrotricha

7(5). Leaflets rigid-coriaceous with revolute margins, the base cuneate; mostly above (700-)1000 m elevation ..... D. obovata

7. Leaflets coriaceous, the margins not revolute, the base rounded to truncate or subcordate; below 800 m elevation ..... 8

8(7). Lower surface of leaflets with fine venation conspicuously raised ..... D. arenaria

8. Lower surface of leaflets with fine venation inconspicuous ..... D. elongata

Distictella arenaria A.H. Gentry, Mem. New York Bot. Gard. 29: 273. 1978.

Slender vine or liana. Shrubby areas adjacent to white-sand savannas, riparian forests, 100-700 m; Bolívar (Salto Pará), northern Amazonas. Colombia (Vichada). Fig. 374.

Distictella dasytricha Sandwith, Kew Bull. 1953: 476. 1954.

Liana. Nonflooded evergreen lowland forests, ca. 300 m; Amazonas (Cerro Yutajé). Ecuador, Peru.

It is possible that the only known Venezuelan collection (Liesner & Holst 21319, MO), like several of the Peruvian ones, is specifically distinct, since the pubescence is much less dense than in typical Distictella dasytricha.

Distictella elongata (Vahl) Urb., Repert. Spec. Nov. Regni Veg. 14: 310. 1916. -Bignonia elongata Vahl, Eclog. Amer. 2: 45, t. 16. 1798.

Liana. Nonflooded evergreen lowland forests, edges of sandy open areas, 100-800 m; Bolívar (northeast of Serranía Marutaní, near Tumeremo), Amazonas (locality unknown). Colombia (Vaupés), Guyana, Suriname, French Guiana, Peru, Brazil, Bolivia. Fig. 375.

Distictella laevis (Sandwith) A.H. Gentry, Mem. New York Bot. Gard. 29: 274. 1978. -Distictella monophylla var. laevis Sandwith, Mem. New York Bot. Gard. 9: 362. 1957.

Usually shrubby, sometimes ± scandent. White-sand savannas, 100-200 m; Amazonas (Caño Yagua, base of Cerro Yapacana). Brazil (Amazonas, southern Pará, RondŁnia). Fig. 376.

Distictella magnoliifolia (H.B.K.) Sandwith, Lilloa 3: 460. 1938. -Bignonia magnoliaefolia H.B.K., Nov. Gen. Sp. (quarto ed.) 3: 136. 1818 [1819].

Liana. Nonflooded evergreen lowland to montane forests, seasonally flooded forests, 0-1000 m; Delta Amacuro (Serranía de Imataca), Bolívar (scattered), Amazonas (common and widespread). Sucre; Costa Rica to Brazil and Bolivia. Fig. 378.

A form with less compressed fruits and reduced seed wings grows sympatrically with typical Distictella magnoliifolia along the Río Mawarinuma near the base of Sierra de la Neblina. No formal taxonomic recognition is accorded this plant, which is intermediate between D. magnoliifolia and water-dispersed D. cremersii A.H. Gentry of French Guiana.

Distictella monophylla Sandwith, Mem. New York Bot. Gard. 9: 361. 1957.

Shrub. White-sand savannas, 100-1700 m; Amazonas (widespread). Adjacent Colombia. Fig. 379.

Distictella obovata Sandwith, Mem. New York Bot. Gard. 9: 362. 1957.

Liana. Upland forests, 700-1700 m; Bolívar (Auyán-tepui, Cerro Sarisariñama, Gran Sabana, La Escalera). Adjacent Guyana.

The collection from Cerro Sarisariñama (Cardona 441, VEN) has glabrescent leaves and is doubtfully referred here.

Distictella pauciflora A.H. Gentry, Ann. Missouri Bot. Gard. 61: 872. 1974.

Liana. Forest edge, ca. 400 m; Bolívar (near Canaima). Endemic. Fig. 373.

Perhaps only a narrow-leafleted form of Distictella magnoliifolia, although the pinkish corolla also seems distinctive.

Distictella porphyrotricha Sandwith, Bol. Soc. Venez. Ci. Nat. 25(106): 48. 1963.

Liana. Montane slope forests, 800-1400 m; Bolívar (Gran Sabana, La Escalera). Guyana (Karowtipu), Brazil (Amapá: Rio Jari). Fig. 377.

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Scientific Comments:
Paul Berry (peberry@facstaff.wisc.edu) or Kay Yatskievych (kay.yatskievych@mobot.org).

 
 
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