290 MACKENSEN: THREE NEW SPECIES OF OPUNTIA 
Lindheimeri. ‘The seeds in the type material agree with those of 
O. macrorhiza. The writer had long suspected that this species is 
a composite one, but after his examination of the material and 
accompanying notes and drawing in the herbarium of the Missouri 
Botanical Garden he has become firmly convinced that such is 
the case. There is another fact which supports this view: Lind- 
heimer, in his notes accompanying the specimens of opuntias, 
uses the expressions ‘“‘kleine Opuntia’ and ‘‘grosse Opuntia,” 
which seems to indicate that he regarded all the small flat-jointed 
opuntias of his region as one species and all the large (more or 
less erect) ones as another, just as at present most of the inhab- 
itants of that region distinguish but two species, if indeed they 
recognize more than one. 
It would seem that in the composition of O. Lindheimeri the 
tall form mentioned contributed the size and habit, O. texana 
the spines, and O. macrorhiza the fruit. All these species occur 
at New Braunfels. The writer has thought best to let the tall 
form, of which he has deposited specimens under the number 
619757 in the U.S. National Herbarium, stand for O. Lindheimer. 
The species described below are closely related, but each, it 
will be seen, differs from any one of the others in several characters. 
The descriptions were drawn from plants growing in their native 
habitat at San Antonio, Texas, where the species are common, 
and the type material was collected in the same locality. 
Opuntia convexa sp. nov. 
Plants from somewhat fleshy terete roots, sometimes attail® 
ing a height of over 1 meter and a breadth of 2 to 3 meters, W! 
low to 
gth of 
15 mm.; spines light brown to reddish below (soon fading t© gray 
ish), but the greater portion of spine pale yellow, strat 
curved, much flattened, mostly twisted, rather stout, 1 
I to 4.5 cm. long, or sometimes longer, I to 5 to an areo €; 
