Cardiospermum

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Cardiospermum

Description

Suffruticose or herbaceous climbers (some American species undershrubs), monoecious. Leaves biternate (Malesian species), with minute stipules at the base. Inflorescences axillary, thyrsoid, mostly (some American species excepted) provided with a pair of tendrils. Flowers unisexual, obliquely zygo-morphic. Sepals 5 or 4 (by coalescence of the abaxial two), free, imbricate, outer two smaller. Petals 4 (abaxial one missing), provided with a scale inside slightly above the base which is only slightly smaller and narrower than the petal itself; Stamens 8, slightly curved upwards, unequal; Ovary 3-angled, 3-eelled, with a short style and a 3-lobed stigma; Fruits capsular, 3-lobed, inflated, 3-celled, septicidal, papyraceous. Seeds with heart-shaped to orbicular hilum (sometimes described as arillode).

Distribution

Africa: present tropical and subtropical America: present worldwide tropical and subtropical: present
About 12 species, mostly restricted to tropical and subtropical America; one species (C grandiflorum) extending to Africa; C. halicacabum is a worldwide tropical and subtropical weed. See .

Ecology

For pollination see .
The mode of dispersal of the American/African species C. grandiflorum, which is sometimes cultivated as an ornamental in Malesia, is very peculiar, and hardly mentioned in botanical literature. The broadly spindle-shaped, inflated fruits are septicidal and sep-tifragal; the dissepiments split into three elliptic, membranous wings, of nearly the same length and width as the fruit. Each seed is well-affixed to the centre of one of these wings. This is in clear contrast to the dispersal of C. halicacabum, the fruits of which are more strongly inflated — globular or even broader — and which seem to be dispersed as a whole, like little balloons.

Morphology

The inflorescence in its most complete form consists of a rather long peduncle with a pair of tendrils (subtended by bracts) slightly below its apex, and a rather short rachis with some pseudo-whorls of 3 lateral branches and a terminal partial inflorescence. The latter, as well as the partial inflorescences terminating the lateral branches, is a few-flowered bostryx. Branches and flowers all have small, lanceolate bracts.
For the ontogeny of the flower see .
For ovule and seed (especially the hilum) see (n.v.).
For embryology see

Notes

1. The synonym Physalis Noroña, cited by Radlkofer with doubt on authority of Hasskarl () is probably erroneous. , cited: "Physalis Halicacabum, Daun capo, nov. cogn." Apparently, he did not intend to describe a new species, but referred to Physalis hali-cacabum Crantz (), a name often treated as synonymous with Physalis alkekengi L. (Solanaceae); the Sundanese vernacular daun capo also refers to Physalis.
2. The genus is most closely related to Urvillea Kunth (Central and South America).

Citation

L., Gen. Pl., ed. 5. 1754: 171
Radlk. - in Engl., Pflanzenr. 98. 1932