J Syst Evol ›› 1983, Vol. 21 ›› Issue (1): 76-78.
• Research Articles •
Xue Xiang-Ji, Mao Jie-Qi, Zhang Zhi-Ming, Hsu Ping-Sheng
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 Trirostellum yixingensis Z.P. Wang et Q. Z. Xie, the type species of Trirostellum with Gynostemma 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 except 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 bereduced 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]. J Syst Evol, 1983, 21(1): 76-78.
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