Vines and Climbing Plants of Puerto Rico and the Virgin Islands

Vines and Climbing Plants of Puerto Rico and the Virgin Islands 73
5. Family ASCLEPIADACEAE
Key to the genera
1a. Stamens with the filaments free; corolla violet, 5 cm long or longer, the floral tube 2 cm long or
longer ......................................................................................................................... 1. Cryptostegia
1b. Stamens with the filaments connate into a tube that is united to the style or to the stigma to form a
gynostegium; corolla white, cream-colored, pale yellow, or pale green, < 2.5 cm long, the floral
tube < 5 mm long ............................................................................................................................... 2
2a. Pollinium erect ................................................................................................................................... 3
2b. Pollinium horizontal or pendulous.................................................................................................... 4
3a. Leaves fleshy, broadly elliptical; inflorescences of 25 or more flowers; lobes of the corona horizontal,
adnate to the staminal tube .................................................................................................... 4. Hoya
3b. Leaves coriaceous, elliptical; inflorescence of 8-20 flowers; lobes of the corona erect, each of them
borne on the basal portion of the dorsal side of the anthers ........................................ 5. Marsdenia
4a. Petals 1.5-2 cm long, lanceolate or oblong ....................................................................................... 5
4b. Petals < 0.5 cm long, ovate, lanceolate, oblong, or deltoid ............................................................. 6
5a. Petals ca. 1.5 mm wide at the base; stems with soft, whitish hairs; leaves cordiform at the base, with
5 acicular glands at the union with the petiole .......................................................... 8. Oxypetalum
5b. Petals ca. 4 mm wide at the base; stems with reflexed, somewhat rough hairs, glabrous when
mature; leaves deeply cordiform at the base, with 2 triangular glands at the union with the petiole
.............................................................................................................................. 3. Gonolobus
6a. Inflorescences with peduncles 1.5 cm long or longer; pedicels 1 cm long or longer..2. Funastrum
6b. Inflorescences with short or subsessile peduncles; pedicels < 1 cm long ........................................ 7
7a. Corolla rotate; pollinium horizontal ................................................................................ 6. Matelea
7b. Corolla campanulate; pollinium pendulous ............................................................... 7. Metastelma
1. CRYPTOSTEGIA
Twining lianas or scandent shrubs, producing abundant milky latex. Stems cylindrical, glabrous,
lenticellate. Leaves opposite, petiolate; blades simple, without glands; stipules interpetiolar, minute.
Flowers in terminal cymes. Calyx campanulate, of 5 more or less elongate sepals; corolla infundibuliform;
corona of 5 filiform lobes; stamens 5, inserted at the base of the corolla, the filaments short and free,
the anthers lanceolate, concrescent around the stigma; ovary superior, bicarpellate, the stigma capitate.
Fruit of 2 divergent, woody, boat-shaped follicles, with numerous ovate seeds, crowned with a tuft of
long hairs. A genus of 2 species, native to the Old World tropics.
Key to the species of Cryptostegia
1a. Corona with bifid lobes; follicles 10-15.4 cm long ............................................... 1. C. grandiflora
1b. Corona with simple lobes; follicles 5.8-13 cm long ................................... 2. C. madagascariensis