RYDBERG: Rocky MounTAIN FLORA 429 
on Pachypodium Nutt.* A generic diagnosis was given but no 
species were cited. In Walpers’ Repertorium (1: 172), the genus 
was again taken up and the three species of Pachypodium found 
in Torrey and Gray’s Flora, were taken up in the same order as 
these. Hence 7helypodium is a mere substitute for Pachypodiuin, 
which name had been used for another genus, and the type of the 
latter genus is the type of the former. The three species of Pachy- 
podium are the following, given in the order in which they appear : 
P. laciniatum, P. integrifolium, P. sagittatum. The last of the 
three need not be considered, for in Torrey and Gray’s Flora it is 
regarded as doubtfully belonging to the same genus as the pre- 
ceding and perhaps belonging to a section of Aradis. The type 
of Pachypodium Nutt., and hence of Zhelypodium Endl., must then 
be either P. aciniatum or P. integrifolium. There is nothing that 
points directly to either of the two, but everything favors the for- 
mer. It is not only the first species mentioned, but it is also the 
only one previously known and figured. It was first described as 
Macropodium laciniatum. Hooker compared it with the original 
M. nivale, gave figures for both and emphasized the differences 
between the two, the oblong anthers and the long, slender pubes- 
ent stipe of JZ. nivale and the linear anthers and the short, stout 
stipe of IZ. laciniatum, Nuttall remarked “ evidently not a Macro- 
podium.” It is evident that he selected the name Pachypodium 
from the short, stout stipe. 
If Macropodium laciniatum Hook. is regarded as the type of 
Thelypodium Endlicher, and the writer can not regard it otherwise, 
the closest: relatives of it we find in 7. utahense Rydb. and the 
groups of 7helypodia on which Dr. Greene based his genus Guil- 
lenta. Itis hard to see how 7 helypodium lasiophyllum Greene, 
the type of the latter genus, can be generically distinct from 7. 
laciniatum (Hook.) Endl. Every character pointed out by Dr. 
Greene for his Guillenia agrees with the latter and is even found 
in Hooker's description. It will be admitted that there are some 
habitual differences, by which 7: /aciniatum is isolated from Gut/- 
lenia, but T. utahense, originally named T. /aciniatum, has the 
habit of that genus, while the flower and fruit are essentially 
those of 7. /asiophyllum. 
*T. &G. FIN, Am. 1:96. 1838. 
