Vines and Climbing Plants of Puerto Rico and the Virgin Islands

Vines and Climbing Plants of Puerto Rico and the Virgin Islands 367
1. CARDIOSPERMUM
Herbaceous vines or erect herbs, lacking latex. Stems simple (cross section with a single vascular
cylinder), angular. Leaves alternate, trifoliolate or biternate; leaflets chartaceous; rachis and petioles
not winged; stipules minute and caducous. Tendrils spirally twisted, in pairs on the axis of the
inflorescence (this sometimes not developed), vestigial in the non-climbing species. Inflorescence of
axillary thyrses, with flowers grouped in lateral scorpioid cymes; pedicels articulated at the base; calyx
of 4 or 5 sepals; petals 4, with a petaliferous appendage on the inner surface; floral disc unilateral, with
2 or 4 glands; stamens 8, the filaments unequal; ovary superior, 3-carpellate, the style simple, with 3
stigmatic branches. Fruit an inflated capsule, membranaceous, septicidal; seeds one per locule, globose
or ellipsoid, with a white reniform or cordiform scar at the base. A genus of neotropical origin, of
approximately 15 species, 3 of which have a pantropical distribution.
Key to the species of Cardiospermum
1a. Petals 5 mm or more in length; glands of the floral disc 2, oblong, 1.2-2 mm long; capsules
ellipsoid, up to 6 cm long………….…………….….………………………..2. C. grandiflorum
1b. Petals less than 5 mm long; glands of the floral disc 4(2), ovoid or rounded, ca. 0.4 mm long;
capsules subglobose or turbinate-trigonal, up to 3 cm long……………………………………2
2a. Plants slightly robust; leaflets sinuate-dentate; inflorescences of 4 or more cincinni; capsules ellipsoid
or globose-trigonal; seed with a reniform hilum .......…….....................1. C. corindum
2b. Plants herbaceous; leaflets deeply lobate or laciniate; inflorescences of 3 cincinni; capsules trigonal,
depressed at the apex; seed with a cordiform hilum …..……………3. C. halicacabum
1. Cardiospermum corindum L., Sp. Pl. ed. 2,
526. 1762.
Fig. 149. M-N
Slightly woody vine, much branched from the
base, that climbs by means of tendrils and attains
1.5-3 m in length. Stems with 5 longitudinal ribs,
pubescent; cross section with a single vascular
cylinder. Leaves alternate, biternate; leaflets 12-
16 × 9-12 cm, chartaceous, the margins sinuatedentate;
both surfaces more or less pubescent,
especially on the prominent venation; terminal
leaflet rhombic, acute or acuminate at the apex
and attenuate at the base; lateral leaflets oblongovate,
acute at the apex, rounded at the base;
rachis and petioles not winged; petioles 2-3 cm
long; stipules minute, early deciduous; tendrils
in pairs, spirally twisted, at the end of short
axillary axes (aborted inflorescences), from which
an inflorescence usually develops. Flowers
functionally unisexual, zygomorphic, in axillary
racemiform thyrses; cincinni more than 4, usually
in more than one whorl. Calyx light green, of 4
sepals, the two outer ones ca. 1 mm long, the inner
ones ca. 2.5-4 mm long; petals white, obovate,
3.5-4.5 mm long; petaliferous appendages slightly
shorter than the petals, fleshy and yellow at the
apex, forming a hood that encloses the apex of
the glands of the disc; disc unilateral, with 4
rounded or ovoid glands, ca. 0.4 mm high;
stamens 8, the filaments unequal, pubescent;
ovary trilocular, with one style and 3 stigmas.
Capsule ellipsoid to globose-trigonal, 2-3 cm long,
inflated, stramineous when ripe. Seed one per
locule, spherical, black, ca. 4 mm in diameter,
with a white, reniform hilum.
Phenology: Collected in flower and fruit in
February and May.
Status: Apparently native, rather common.
Distribution: In disturbed areas and dry forests
at low elevation. Also on Desecheo, Mona,
Vieques, Guana Island, St. Croix, St. John, and
St. Thomas; throughout the tropics and subtropics.
Cultivated for its curious capsules.
Public Forests: Guajataca, Guánica, and
Mona.