38 Contributions from the Gray Herbarium 
Leptopharynx, Monothrix, Perityle and Nesothamnus are distin- 
guished mainly upon the character of the pappus. It is true that 
the appendages of the style-branches of Leptopharynz are subulate- 
filiform; but those of Monothrix are subulate and those of Perityle 
and Nesothamnus, even though short are slender. In fact this tribe 
is characterized as having both the style-branches and their 
appendages slender. This character, therefore, which exists in 
every degree, is scarcely suitable for the definition of genera es- 
pecially since it is not concomitant with a single constant character. 
The only really diagnostic character remaining to Leptopharyna,— 
then, is the shape of the corolla-throat, as noted above. So far as 
I have been able to determine the throat of the disk-corollas of 
this group of species is, indeed, cylindric but this minute difference 
is surely not sufficient for assigning to these plants generic dis- 
tinction. With Leptopharynz sunk in Perityle, the invalidity of 
Monothrix and Nesothamnus becomes apparent. The latter 
genus, even with Perityle restricted as by Rydberg, was palpably 
weak for it rested upon a single character peculiar to it, the tomen- 
tose pubescence. All other “ characters ” it shared in greater OF 
less degree with Perityle. And Monothrizx was hardly more distinct 
since it differed constantly only in the nature of the pappus which 
(when present) consisted of one awn instead of a crown of small 
squamellae and 0-2 awns. 
But the futility of attempting to divide Perityle into several 
genera becomes even more evident when the general characters 
(including the aspect) of the plants concerned are taken into ac 
count. Perityle in the strictest sense consists of herbaceous annuals 
or perennials but there are a number of species which are more or 
less suffruticose at base and, in this characteristic, they simulate 
those species which Rydberg would treat under other generi¢ 
names as discussed above. I am aware that this argument Mg” 
be carried still further and applied to Laphamia. But Laphama 
as restricted now, although not as well marked as might be desired, 
is definitely distinct by those characters of involucre 
pointed out, and if it is to remain so certain species heretofore 
referred to it must be removed as Rydberg has done. In ei 
delimination (and consequent better understanding) of Lapham4, 
the treatment in the North American Flora is of genuine service 
because the attempted maintenance of Gray’s genus upon aie 
