Stephania
Content
Description
Climbers, mostly slender.
Leaves with petioles usually geniculate at base;
Inflorescences axillary or arising from old, leafless stems, usually composed of peduncled umbelliform cymes which are solitary or racemosely arranged, at least the lst(-2nd) orders of branching umbellate (in Mal. spp.), the ultimate branching sometimes irregu-lar, or sometimes the cymes condensed to disciform capitula.
Seed horseshoe-shaped.
Distribution
Asia-Tropical, in the warmer parts, mostly tropics, of the three continents in the Old World present
About 35 spp. in the warmer parts, mostly tropics, of the three continents in the Old World; throughout Malesia.
Notes
The Malesian species of Stephania fall into DIELS' sections Thamnothyrsa and Eustephania. These sections are not maintained in the following account since the distinctions between them, which were based on the position and form of the inflorescence, are unreliable.
As to life-form, the species differ: S. japonica, S. psilophylla and S. venosa seem to have annual or seasonal stems, while S. corymbosa and S. zippeliana have perennial woody stems.
The form of the inflorescence is specifically important in Stephania; in all the Malesian species its organisa-tion is based on one or more peduncled, umbelliform cymes, which show varying degrees of condensation in different species. In S. montana and 5. corymbosa the cymes are lax and bear pedicellate flowers. In S. japonica the flowers are sessile in subcapitate globose clusters. Extreme condensation of the cyme-branches occurs in S. capita ta and S. dictyoneura resulting in a solid, disciform receptacle on which the flowers are very densely crowded. The composition of the inflorescence is usually either a solitary umbelliform cyme as in S. japonica and S. venosa or a racemose arrangement of umbelliform cymes as in the other species. The former composition is a character used by DIELS for his section Eustephania and the latter for his section Thamnothyrsa. In S. psilophylla, however, a racemose arrangement of cymes is usual but solitary cymes also occur.
Externally, the fruits of different species are similar; the differences are to be found internally. The remarkable ornamentation of the endocarp is usually distinct for each species. There are 2 or 4 rows of processes in the form of ridges, hooks, rods or plates, the rows running longitudinally along the dorsal surface of the endocarp. Each species has a characteristic range in the number and form of these processes.
As to life-form, the species differ: S. japonica, S. psilophylla and S. venosa seem to have annual or seasonal stems, while S. corymbosa and S. zippeliana have perennial woody stems.
The form of the inflorescence is specifically important in Stephania; in all the Malesian species its organisa-tion is based on one or more peduncled, umbelliform cymes, which show varying degrees of condensation in different species. In S. montana and 5. corymbosa the cymes are lax and bear pedicellate flowers. In S. japonica the flowers are sessile in subcapitate globose clusters. Extreme condensation of the cyme-branches occurs in S. capita ta and S. dictyoneura resulting in a solid, disciform receptacle on which the flowers are very densely crowded. The composition of the inflorescence is usually either a solitary umbelliform cyme as in S. japonica and S. venosa or a racemose arrangement of umbelliform cymes as in the other species. The former composition is a character used by DIELS for his section Eustephania and the latter for his section Thamnothyrsa. In S. psilophylla, however, a racemose arrangement of cymes is usual but solitary cymes also occur.
Externally, the fruits of different species are similar; the differences are to be found internally. The remarkable ornamentation of the endocarp is usually distinct for each species. There are 2 or 4 rows of processes in the form of ridges, hooks, rods or plates, the rows running longitudinally along the dorsal surface of the endocarp. Each species has a characteristic range in the number and form of these processes.