302 PROCEEDINGS OF THE AMERICAN ACADEMY 



Fertile prairies, or sterile places, on the Upper Missouri and Yel- 

 lowstone, to the mountains and south to Santa Fe. — Size and shape 

 of the joints variable ; fruit-bearing joints compressed, 1| - 2 inches 

 long, 1- 1|- wide, and |-f thick ; others smaller and more tumid. 

 Leaves a line long, hardly longer than the large pulvilli, red. Pul- 

 villi 4-6 lines apart, bristles very few, short, whitish, on the old joints 

 a little more numerous, coarser, dirty yellow. Lower radiating spines 

 2-4 lines long; central spines 6-10 lines long, the other interior 

 spines 3-8 lines long, often similar to the smaller lower spines. 

 Fruit rather fleshy through the winter, getting dry in spring, nearly 

 an inch long, with 20-25 pulvilli, of which only the upper ones bear 

 a few short spines. Seeds few, usually only 5 or 6 in each fruit, 3 

 lines in diameter, with a wide and thick obtuse corky margin. — Often 

 sterile, but abundantly propagated by the fragile joints, 



28. O. BRACHYARTHRA, E. & B. 1. c. : adsccndens ; articulis ovatis 

 orbiculatisve tumidis ssspe subglobosis tuberculatis ; pulvillis confer- 

 tis parce setulosis ; aculeis 3-5 validioribus 1-2 fuscatis patulis vel 

 suberectis, cseteris deflexis ; floris parvi ovario subgloboso pulvillos 12 

 - 15 vix aculeolatos gerente ; stigmatibus 5. 



Inscription Rock near Zuni. — The short and tumid joints (10- 15 

 lines long) resemble the joints of a finger; the pulvilli 2-4 lines 

 apart, even in the oldest parts of the plant with very few bristles ; 

 longer spines 9-12 lines long, terete. Ovary less than half an inch 

 long. Flower apparently an inch in diameter. — Perhaps too near 

 O. fragilis ; but in the absence of good flowers and fruit, it is im- 

 possible to say whether it does not belong to even a different section, 

 perhaps to the Glomerate^, Salm. 



Subgen. 3. Cylindropitntia, E. in B. C. R. Articuli cylindracei : 

 flores magni vel parvi : bacca plerumque sicca : semina immai'ginata 

 seu vix marginata : embryo circa albumen copiosius subcircularis ; 

 cotyledones contrarian seu obliquse, subinde parallelse. 



§ 1. ClavatcB : prostratse : articuli breves, clavati, adscendentes, tex- 

 tura lignosa laxe reticulata : flores flavi majusculi : bacca sicca, 

 pulvillis numerosis setosissimis stipata, floris rudimentis persisten- 

 tibus coronata. 



29. O. CLAVATA, E. in Wish Rep. : articulis breviter clavatis la!te 

 viridibus ; tuberculis ovatis ; foliis subulatis minutis ; aculeis albidis 



