Commelinantia, a new genus of the Commelinaceae 
B. C. THARP 
(WITH PLATES IO AND IT) 
Few if any families of plants have members in more urgent 
need of field study than are those of the family Commelinaceae. 
Their evanescent corollas, which it is difficult even to bring 
from field to laboratory without injury; the delicate shades of 
color which are lost in pressing; and their succulent stems, 
which shrink tremendously in drying, make field study imperative 
if one is to get any adequate idea of these delicate details as they 
appear in the growing plants. Since 1919 I have had abundant 
opportunity for field study of a very interesting member of the 
family, a species first described by Torrey* as Tradescantia 
anomala and latter transferred by C. B. Clarket to the genus 
Tinantia, where it has remained to the present time. 
Torrey’s description, based upon specimens from Texas, (one 
of Wright’s, and one of Thurber’s), preserved in the herbarium 
of the New York Botanical Garden, is surprisingly good, con- 
sidering that it was drawn wholly from dried material. Suc 
details of general habit, sepals, petals (except color), filaments 
(except that of the posterior stamen), anthers, style, stigma, 
and ovules, as are pointed out, are correctly described. The 
greatest error into which his material led him seems to have 
been in considering the ovary and capsule two-celled. He also 
described the seeds as being ‘‘as in the rest of the genus,’’ which 
is incorrect. The wonder is that, having examined his material 
so carefully as to be able to write such an accurate description, 
he could feel justified in assigning this species to the genus 
Tradescantia. That he was none too confident of its having been 
correctly assigned is abundantly testified by the specific name, 
by legendst on the sheets containing his specimens, and by his 
*U. S. and Mex. Bound. i 225. geo 
{t DeCandolle, Monog. Phaner. 3: 28 
t Wright ’s specimen is labelled * Wright, pee Commelyna anomala, Torr. 
Tradescantia anomala Torr.,” the word “Commelyna’’ being stricken out. 
Thurber’s specimen is labelled “Thurber, San Antonio Texas, May 1853. 
Commelyna rhodantha, Torr 
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