59 
of this the region is a network of ranges and volcanic peaks where the 
Tropical vegetation reaches 8000 feet altitude, and the peaks sometimes 
reach the Lower Temperate, but rarely they extend higher to the Middle 
Temperate, and only very rarely as on Orizaba, Popocatapetl, and Mt. 
Colima do they reach the alpine. The lowlands about Colima and 
Tampico southward have the dense vegetation and summer rains of 
the humid Tropics. This is about as far as species of Astragalus extend 
except a very few. The plateau floor from Arizona southward is 
Tropical rower California has a low range of mountains the entire 
length but the flora rarely gets up out of the Tropical San Pedro 
Martir is an exception. 
The upper limits of the Tropical in the United States rarely 
reaches 3000 feet altitude. In the Arizona region they are about 4000 
feet, and rise as you go southward. : 
The upper limits of the Lower Temperate life zone reach about 
5000 feet in the Great Basin, but drop to about 1000 feet in the Colum- 
bia Basin. In the south in Arizona they often reach 8000 feet altitude, 
Topographical details can be worked out on the map, and the 
general zonal limits are best seen there, 
NOMENCLATURE. 
It has been my plan to make as few changes in names as possible. 
The Vienna Code has been followed in the main and therefore the 
oldest published name has been retained, except the meaningless 
Astragalus astragalinus, for which I have substituted the A. andinus 
of Nuttall. It is however my judgment that the Grayan method of 
retaining the oldest name in the genus is better and productive of little 
confusion, while the present method produces endless confusion. I 
do not adopt the dictum “Once a synonym always a synonym,” but I 
have used the name of a species even if the same name has been used 
for a species before that was a synonym of some earlier species, or 
belonged to another genus. I have rejected Greene’s substitutes for 
Sheldon’s hybrid names, for the reason that if we reject hybrid names 
we shall have to go much farther back than Sheldon. 
I retain Astragalus for the reason that it is the earliest name and 
the one generally accepted by the botanical World. The fact that 
it is preceded in the Species Plantarum by Phaca should not require the 
rejection of the genus, for the genus was proposed by Tournefort and 
retained by Linnzus in his Systema before Phaca was created. 
Priority is the ony true basis for nomenclatural stability but no 
one however zealous an adherent of this dictum accepts it without 
the narrowest limitations. If we could ever know what was the true 
priority in each case it would require the renaming of almost every 
genus and species in the world as I have already pointed out. This be- 
ing out of the question the next thing is the general consent of botan- 
ists. This has crystallized so that at the present time there is a general 
assent to main points, which is that old names shall not be changed on 
a technicality, and that in other respects 1753 shall be the beginnine 
date of nomenclature. The exceptions of the Vienna Code cover most 
of the desirable reservations from the strict application of priority. 
There should be certain other exceptions of genera. There should 
be the abrogation of the rule about Latin descriptions, and the rejec- 
tion of all genera proposed in early days that were not accompanied  — 
by species. This will rule out the genera of Adanson, Necker, and | 
others, unless they were provided with species by others before any sone 
other generic names were proposed for them. 
zx 
