On the Identity of Trirostellum Z. P. Wang et Q. Z. Xie

Xue Xiang-Ji, Mao Jie-Qi, Zhang Zhi-Ming, Hsu Ping-Sheng

Received:1900-01-01 Revised:1900-01-01 Online:1983-02-18 Published:1983-02-18
Contact: Xue Xiang-Ji

Abstract:

According to Wang and Xie, their recently published genus Trirostellum is

distinguished from its allied genera by a number of characteristics: (1) the stamens

with their filaments coherent into a central column; (2) the female flowers possessing

rudimentary stamens; (3) the ovary 3-celled, with one ovule in each cell; (4) the fruits

dehiscent, 3-rostrated at the apex; (5) the fruits possessing persistent perianth; (6)

the seeds tuberculate and winged. However, upon a careful comparison of Trirostell-

um yixingensis Z.P. Wang et Q. Z. Xie, the type species of Trirostellum with Gyno-

stemma pentaphyllum (Thunb.) Mak., the type species of Gynostemma Bl. and some

other species of Gynostemma as well,we have found that the representatives of the

above two genera are identical in most of the important diagnostic characteristics ex-

cept that the fruits of the former genus are dehiscent with three long beaks at the

apex, while the fruits of the latter genus are indehiscent with very short beaks.

Besides, results obtained from chromosome counting haove shown that the somatic

chromosome number of Trirostellum yixingensis is 2n=22, while that of Gynostemma

pentaphyllum is 2n=28.Yet these morphological and chromosomal differences seem

not sufficient for generic demarcation. We, therefore, suggest that Trirostellum be

reduced to a sectional or subgeneric rank of Gynostemma Bl.

Xue Xiang-Ji, Mao Jie-Qi, Zhang Zhi-Ming, Hsu Ping-Sheng. On the Identity of Trirostellum Z. P. Wang et Q. Z. Xie[J]. .

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