i 1898] BRIEFER ARTICLES 12 
contain perfect seeds, while the secondary ones are generally sterile; 
however, an entire cluster may sometimes be found with perfect seeds. 
Cattle feed upon the succulent spineless fruits, but in doing so the 
burr like terminal joints frequently become detached and adhere to 
their heads, the innumerable barbed spines piercing the flesh and 
causing injurious wounds if not removed. Many small bristles cover 
the pulvini of the fruit at maturity and accumulating in the stomachs 
of the cattle feeding upon them produce large phyto-bezoars. In color 
the fruit at maturity is pale green, a little lighter shade than the epi- 
dermis of the stem or immature fruit. 
The plant illustrated in Garden and Forest 8: 325 was removed 
some eighteen months ago from the mesa to the cactus garden of the 
University. Although the plant is one of the largest specimens in 
this vicinity and at least one hundred years old, it did not seem to suf- 
fer from transplanting. In this specimen the entire root system, with 
the exception of a few long surface roots, was a mass of short fibers 
springing directly from the trunk a few inches below the surface of the 
soil, none reaching to a greater depth than two and one-half feet. 
What has been said of O. fulgida applies almost equally as well to 
0. fulgida mammillata. The differences seem to be in that the variety 
has thicker, shorter joints; fewer, shorter spines; more prominent, 
shorter tubercles; and is a plant of the foothills instead of the open 
mesa. The description as given by Dr. Coulter? gives the variety as 
more tree-like than the species. In my observations the reverse is 
Seat haga the spines on the terminal joints are usually four to 
and ‘sed ag may have twenty or thirty to the tubercle. The flowers 
are practically identical. 
the hon weg Engelm. is the most abundant cylindrical opuntia on 
ines bic oe oe iis mountains of southern Arizona. It is a small 
and bearin 308 eight inches in diameter in well developed specimens, | 
tes hie a Many irregular branches with terminal Beare: sometimes 
€ngth. It has smooth, light-brown bark, without spines 
er limbs. The epidermis of the younger branches 
Steen to purple. The terminal joints are intermediate in 
Spinostor and O. tetracantha, while rather promi- 
ermediate in length between O. arborescensand 0. 
a 
— and Forest g: 324. 
butions from the U. S. National Herbarium 3 : 449. 
