Vines and Climbing Plants of Puerto Rico and the Virgin Islands

Vines and Climbing Plants of Puerto Rico and the Virgin Islands 77
4. HOYA
Twining vines or epiphytes, herbaceous or slightly woody, sometimes subshrubs, producing abundant
milky latex. Leaves opposite; blades simple, fleshy, the upper surface with minute triangular glands
where they join the petiole; intrapetiolar stipules minute or absent. Flowers usually numerous, in
axillary, umbelliform, pedunculate or sessile racemes. Calyx of 5 free sepals that have a gland at the
base on the inner surface; corolla rotate or campanulate, the tube short, cylindrical or urceolate, the
petals fleshy or waxy; corona simple, with 5 horizontal segments adnate to the staminal tube; stamens
5, inserted at the base of the corolla, the filaments fused to a gynostegium, which is not markedly
capitate, the anthers with a distal appendage; pollinium erect and solitary; ovary superior, bicarpellate,
the stigma conical. Fruit of 2 slender follicles; seeds numerous, crowned with a tuft of long hairs. A
genus of approximately 300 species, native to southern Asia, Malaysia, and Australia, some of which
are cultivated as ornamentals throughout the tropics.
1. Hoya australis R. Br. ex Traill, Trans. Hort.
Soc. London 7: 28. 1830.
Fig. 26. H-K
Mata de cera, Wax plant
Slightly woody vine, twining, 6-7 m in length,
with abundant milky latex. Stems cylindrical,
puberulous, green. Leaves opposite; blades 5-12
× 2.5-5.5 cm, oval, elliptical, or ovate, fleshy,
glabrous, acute, acuminate, or subrounded at the
apex, the base obtuse or rounded, with 3-5 minute
triangular glands at the union with the petiole,
the margins entire, the venation pinnate; upper
surface dull, the midvein sunken; lower surface
dull, with a prominent midvein and puberulous;
petioles subcylindrical, 1-2 cm long, pubescent.
Flowers numerous, arranged in umbelliform
racemes, clustered at the tip of a peduncle; basal
5. MARSDENIA
flowers early deciduous; bracts overlapping and
persistent on the peduncle; peduncle 1.5-3 cm
long; pedicels 2-4 cm long, pale green. Calyx
whitish green, of lanceolate sepals, ca. 3 mm long;
corolla rotate, white, with a bright pink to purple
center, the lobes broadly ovate, 4-5 mm long,
densely papillose inside; corona white, the
segments 3 mm long. Follicles linear, cylindrical,
6-13 cm long; seeds oblong, ca. 4 mm long, with
long, whitish, silky hairs.
Phenology: Collected in flower in December.
Status: Exotic, commonly cultivated in Puerto
Rico and the Virgin Islands.
Distribution: Native to Australia; widely
cultivated in the Neotropics.
Commentary: This species has been cited as
Hoya carnosa (L.) R.Br. by Britton and P. Wilson
(1925) and by Liogier (1995).
Herbaceous or woody vines, twining, less frequently erect shrubs, with abundant milky latex. Stems
cylindrical or angular, lenticellate or with abundant cork when mature. Leaves usually opposite, petiolate;
blades simple, the upper surface with 2 or more minute glands where they join the petiole; intrapetiolar
stipules minute. Flowers in subaxillary or terminal, umbelliform or racemose, dichasial or paniculiform
cymes, with few to many flowers. Calyx of 5 deep or short sepals, with 1-2 (3-5) glands at the base on
the inner surface, or without glands; corolla rotate, campanulate, urceolate, or hypocrateriform; corona
absent or of 5 segments, each of them borne on the basal portion of the dorsal side of the anthers;
stamens with the filaments fused to a sessile or stipitate gynostegium; stamens 5, the anthers erect,
usually rectangular; pollinia erect; ovary superior, bicarpellate, the stigma conical or depressed. Fruit
a fusiform or ovoid, ellipsoid, or angular follicle, winged at the margin; seeds numerous, crowned with
a tuft of long hairs. A tropical and subtropical genus of approximately 300 species.