Vines and Climbing Plants of Puerto Rico and the Virgin Islands

278
Vines and Climbing Plants of Puerto Rico and the Virgin Islands
19. RHYNCHOSIA
Herbaceous or woody vines, twining. Leaves alternate, trifoliolate, the lower surface with numerous
yellow resinous dots; stipules deciduous; stipels minute. Inflorescences of axillary racemes, with the
flowers sparse or clustered; bracts minute, persistent or deciduous. Calyx campanulate, with 4-5 elongate
lobes; corolla yellow, the standard obovate or rounded, slightly retuse at the apex, unguiculate and
auriculate at the base, the wings unguiculate, with a curved appendage at the base of the inner margin,
the keel scarcely longer than the wings; stamens 10, monadelphous or diadelphous; ovary superior,
short-stipitate, with few or numerous ovules, the style glabrous, curved, the stigma capitate. Fruit an
oblong legume, flattened, apiculate at the apex, usually dehiscent by valves that twist on opening;
seeds few or numerous, flattened, rounded or elliptical. A genus of about 200 species, of pantropical
distribution.
Key to the species of Rhynchosia
1a. Robust lianas that attain 8-10 m in length; mature stems flattened, forming a ribbon up to 2.5 cm
wide; seeds red and black ….………………………………….... 2. R. phaseoloides
1b. Slightly woody vines, usually less than 5 m in length; mature stems cylindrical, less than 5 mm in
diameter; seeds brown ……………………………………………………………. 2
2a. Lower surface of the leaflets with the tertiary venation not prominent; calyx 2.5-3 mm long, the
sepals short-subulate, as long as or twice as long as the tubular portion of the calyx
..............…………………..…..……………………………...……………………1. R. minima
2b. Lower surface of the leaflets with the reticulate tertiary venation prominent; calyx 6-10 mm long,
the sepals linear-lanceolate, three times as long as the tubular portion of the calyx
...................……………..…….…………………………………….…………….3. R. reticulata
1. Rhynchosia minima (L.) DC., Prodr. 2: 385.
1825.
Fig. 111. E-H
BASIONYM: Dolichos minimus L.
SYNONYMS: Rhynchosia minima var. lutea Eggers
Rhynchosia minima var. pauciflora Kuntze
Dolicholus minimus (L.) Medic.
Frijolillo, Habilla
Non-woody vine, twining, attainig 1-4 m in
length. Stems slender, densely pubescent, striate,
cylindrical, with numerous resinous dots in the
furrows. Leaves alternate, trifoliolate,
chartaceous; margins entire, slightly revolute;
upper surface dull, glabrous or white-pubescent,
especially on the veins, with numerous orange
resinous dots; lower surface pale green, glabrous,
puberulent or pubescent, with minute orange
resinous dots and the primary and secondary
venation prominent; terminal leaflet rhombic, 0.9-
2.8(7.5) × 0.6-2.8(6.3) cm, the apex acute or
obtuse, the base cuneate; lateral leaflets
asymmetrical, elliptical-ovate, slightly smaller
than the terminal leaflet, the base obtuse;
petiolules densely pubescent, 1-1.5 mm long;
petiole striate, densely pubescent, 1.5-2 cm long;
stipules subulate, 2-2.5 mm long, densely
pubescent; stipels subulate, ca. 3 mm long.
Inflorescence a raceme, as long as or longer than
the leaves. Calyx green, the lobes lanceolate, 2-3
mm long; corolla yellow with purple or brown
venation, the standard 5 mm long, orbicularovate;
wings oblong, unguiculate, 4-5.5 mm long,
with resinous dots. Legume falcate to oblongovate,
flattened, minutely villous, 9-20 × 3-5 mm,
with a beak at the apex. Seeds 2-3, ovate-reniform,
dark brown to almost black, 3-4 mm long.
Phenology: Flowering and fruiting throughout
the year.
Status: Probably exotic, naturalized, very
common.
Distribution: Abundant on fences and in
weedy places at middle and lower elevations. Also
on Mona, Vieques, St. Croix, St. John, St. Thomas,
Tortola, and Virgin Gorda; generalized in the
tropics and subtropics of the world. Although this