Monographs Details: Tapeinostemon capitatum Benth.
Authority: Maguire, Bassett. 1978. The botany of the Guayana Highland--part XI. Mem. New York Bot. Gard. 32: 1-391.
Discussion:6. Tapeinostemon capitatum Bentham, Hook. Jour. Bot. Kew Misc. 6: 194, 195. 1854.
Tapeinostemon borrerioides Bentham in sched. Knobl. Bot. Centralbl. 60: 355. 1894. Type. Ad flumina Casiquiari, Vasiva et Pacimoni, 1853-4. R. Spruce 3293 (K, NY. "Original im Berliner Herbar.").
Type. Prope Panure ad Rio Uaupes, Oct 1852, Jan 1853. R. Spruce 2493 (K, NY).
The only two collections of Tapeinostemon capitatum known to me are Spruce 2493 and Spruce 3293 cited above, respectively the type of Tapeinostemon capitatum, and the sheet on which in Bentham's hand is written "Tapeinostemon borrerioides sp.n." These two collections without question represent the same species. Curiously, this elusive small herbaceous annual has not been re-collected despite the active field work in the region of so many subsequent field botanists.
The question of pistil structure is again laid to rest. The delineator for Tapeinostemon capitatum in Flora BrasUiensis shows a well defined style as part of the illustrated pistil (TAB LVIII. FIG IV, 10, Fl. Bras. Vol. VI, Pars 1, 1860), citing in the text R. Spruce 2493. Now, from a prepared vertical section of a midmature pistil from Spruce 3293, we demonstrate the presence of the well developed style. In this section the style base has become enlarged bulbose, and shows evidence of an approaching subsequent normal dehiscence. This permanent slide is on file at The New York Botanical Garden.
It is, therefore, evident that the Bentham characterization "Stylus vix ullus" must be disregarded. For Tapeinostemon capitatum (and all other species of the genus at this time known) there is formed a well defined style. The manner of style loss is of interest and may be distinctive within the genus. Taxonomic considerations thereto would necessarily await field study and ample series of specimens.