作 者 ：Bao Bo-jian, Li An-jen
期 刊 ：植物分类学报 1993年 2期
Keywords:Atraphaxis, system, pollen,
Abstract:
The genus Atraphaxis is found mainly in gravel steppes, sandhills and
stony slopes or desert, with only a few species in meadow or river valleys. In
China there are two sections and eleven species (including three varieties), which
are distributed mainly in the northwest, with a few in the northeast and the north.
Characters of the genus were compared and analyzed in the present work. Outer
perianth segments 2, small, reflexed in fruit, inner perianth segments 2 or 3, large,
erected and enveloping the nut. The embryo is curved, but those in the other
genera of Atraphaxideae are straight. The curved embryo is the primitive
character, because most species of the order Caryophyllales are of a circular
embryo, which is belived to be ancestral in the Polygonaceae. The Pollen
ornamentations of Atraphaxis are striate or striate-reticulate, different from those of
the other genera. A new system of the tribe Atraphaxideae in proposed in the
present paper. Based on the character analysis of the species in China, the pres-
ent authors believe that Sect. Tragopyrum is more primitive than Sect.
Atraphaxis. According to the distribution, the genus Atraphaxis might originate
in Kazakstan, where not only are most species found, but also the most primi-
tive species, like A. muchketovii, as considered by A. N. Krasnov, are found.
Central Asia is considered as the distribution centre and origin centre of the
genus Atraphaxis.