

Macbride — Revision of Mirabilis, subgenus Hesperonia 21 
species (known to be variable in the degree of pubescence) are 
never so nearly smooth throughout. But the diagnostic feature 
of M. laevis is not to be found alone in the lack of pubescence but 
rather consists of this character taken in conjunction with the 
nature of the involucre. The involucral lobes are ovate-lanceolate, 
attenuate and usually longer than the tube. They thus suggest 
those of M. tenuiloba but are shorter and broader at base. There 
is a form of M. californica which has somewhat elongate acute 
involucral lobes but the involucre is relatively short-campanulate 
in the manner of typical M. californica and I have seen no speci- 
mens I should regard as transitional to M. laevis. For the present, 
then, or until there is definite evidence that M. laevis is variable 
in one or the other of the characters discussed above it seems de- 
sirable to regard it as a local species confined to the region of 
Magdalena Bay rather than to refer to it as a mere variant the 
more distinctly pubescent M. californica variable as the latter is 
in the matter of pubescence but fairly constant in the character 
of involucre.- Besides M. tenuiloba, M. laevis and M. californica it 
seems possible to distinguish two other plants as species, M. 
Heimerlii and M. oligantha. The salient feature of the former is 
found in the fruit. This is remarkably spherical so that it resem- 
bles a tiny marble. Although it is true that there seems to be some 
variation in the shape of the fruit of M. californica in the exami- 
nation of considerable fruiting material I have found no anthocarps 
that were not definitely longer than thick. The latter species 
(M. oligantha), on the other hand, has greatly elongate fruits and- 
moderately slender involucral lobes; it is apparently a distinct 
Species. Its involucre suggests a relationship to M. tenuiloba. 
This plant occurs in two forms. The typical state is viscid- 
pubescent to the base and the fruiting involucres are mostly 13- 
15 mm. long. The other form, described by Standley as M. poly- 
phylia, is glabrous below and the involucres are usually somewhat 
shorter even in fruit (10-12 mm. long). Standley in his key 
character, 1. c. 233, separates these plants not only upon the 
characters just noted but also upon the relative size of leaves and 
thickness of stems. It seems evident even from the rather few 
Specimens I have seen that these supposed differences are individ- 
ual in character and are not concomitant with the extent of pube- 
Scence or the size of the involucre. M. polyphylla at best there- 
