146 SYNOPSIS OF THE CACTACEHX OF THE UNITED STATES. 
Fruit an inch long; upper pulvilli with 4-6 bristly spines. Seeds 3} lines in diameter, among the largest in this 
genus. 
. O. Missourrensis, DC. (Cactus ferox, Nutt. bas prostrata ; articulis obovatis vel eran tuber- 
eat i minutis ; pulvillis subvonfertis stramineo-setosis, omnibus armatis ; aculeis 5-10 exterioribus area 
setiformibus albidis, 1-5 interioribus robustis albidis sen pn seen tibus ; floris flavi intus sonnet ovario obovate 
vel subgloboso spinuloso ; stigmatibus 5-10 viridibus; bacca spinosa, umbilico plano; seminibus magnis irregu- 
laribus. 
Var. a. RUFISPINA, E. & B.: articulis orbiculatis ; aculeis interioribus 3-5 validis fuscis ; bacca ovata. [300] 
Var. 8. PLATYcARPA, E.: articulis obovato-orbiculatis; aculeis interioribus subsingalis validis fuscis; 
bacca dopresse-globou late vewhidinct 
Var. y. MICROSPERMA, E. : saints aculeisque praecedentis ; bacca ovata breviter aculeolata ; seminibus minori- 
bus anguste marginatis. 
Var. 8. SUBINERMIS, E.: articulis elongato-obovatis, pulvillis subremotis inferioribus inermibus, superioribus 
aculeos paucos breves gerentibus. 
Var. e. ALBISPINA, E. & B. : articulis late obovatis ; aculeis 6-12 omnibus albis gracilioribus ; bacca ovata. 
ar. ( TRICHOPHORA, E. & B.: articulis ovatis; pulvillis confertis; aculeis 10-18 setiformibus (in articulis 
vetustis seimmenoaioeibus) capillaceis flexuosis ; bacca ovata; seminibus maximis. 
From the upper Missouri to the Canadian ; eclnctwatiy occupying the western plains, but also on the mountains 
towards Santa Fé and west of it. — The last-mentioned variety (which I would consider a distinct species, were it no 
for the var. albispina, which seems to unite it with the others) has been found only on the mountains near Albuquer- 
que: all the other forms occur on the upper Missouri, and a. and ¢, also on the Canadian. Other and intermediate 
forms of this variable but nevertheless well-characterized species will no doubt be found in the wide territory inhabited 
by it. It flowers in May and June. — Joints 2-4, rarely 4-6 inches long, and 2-3} inches wide, light green ; leaves 
1}-2 lines long; larger spines 1-14, rarely 2 inches long, in 8. not more than 3-6 lines long. Flowers 2-3 inches in 
diameter, with ain green stigmata forming a compact head. Fruit 1-1} inches long, with shorter or longer spines, 
and a rather shallow sicbtlioad, Var. 8. has a remarkably large flat fruit. Seed generally about 3 lines, but in y. 
only 2 lines, in diameter. 
. O. spHa#RocarPA, E. & B. 1. c.: diffusa; articulis renee tuberculatis; pulvillis confertis stramineo- 
setosis sleri isque inermibus, summis solum eviTecs 1-2 os patulosve majores gerentibus, adjectis spe 1-3 
brevioribus ; bacca globosa vix aculeolata; seminibus mediis 
Senuisten near Albuquerque, New Mexico. — Joints 3 inches in diameter, strongly tuberculated ; pulvilli 
4 or 5 lines apart; spines 6-12 lines long, reddish-brown, often single or 2 or three together, with or without [301] 
smaller ones, which never occurs in any form of O. Missouriensis, where a large number of small setaceous 
spines is found, whether larger ones are present or not. Fruit 9 lines in diameter, with a small flat umbilicus. Seeds 
24 lines in diameter. 
* * Articuls tumidt ovati. 
25. O. eRtnaceEA, E. & B. 1. c.: adscendens; articulis ovatis seu teretiusculis; pulvillis confertissimis omnibus 
armatis ; aculeis 5-10 gracilibus rubellis, 3-5 leunipitia ; bacca ovata aculeolata; seminibus magnis subregularibus. 
Near the Mojave, between the Colorado and the California mountains. sciheiie 2-24 inches long, 1-14 broad, and 
4-} thick, sometimes almost cylindrical, densely covered with large white pulvilli, which are only 2-3 lines apart. Spines 
6-14 or even 20 lines long, slender but stiff. Fruit an inch or more in length. Seeds nearly 3 lines in diameter. 
26. O. ArENARIA, E. in B. C. R.: adscendens ; articulis obovatis compressis seu teretiusculis tuberculatis ; foliis 
minutis ; pulvillis subconfertis pened setosis ; petilais 1-4 robustioribus albidis fuscatisve, cum inferioribus breviori- 
bus 2-6 albis; floris sulphurei ovario obovato ; petalis emarginatis ; stigmatibus 5; bacca oblonga spinulosa ; wm- 
bilico infundibulifiensis seminibus is i i 
Sandy bottoms of the Rio Grande near El Paso: ieee May. — Spreading 2-3 feet, }-1 foot high ; roots stout, 
creeping horizontally ; joints 14-3 inches long, 1-2 inches wide, and }-? thick, more strongly tuberculated than the 
ied species ; leaves only a line long; pulvilli 3-5 lines apart, very bristly, especially on the old joints ; upper spines 
9-15 lines ake Flower 2-2} inches in diameter. Fruit about an inch long. Seeds 23-3 lines in diameter. This 
is the es one of our Cactacee on which the Cochenille has been found. 
. O. FRAGILIS, Haw. (Cactus fragilis, Nutt.): subdecumbens ; articulis parvis ovatis subcompressis tumidis 
vel oe ek vix tuberculatis nitide viridibus ; foliis minutis ; pulvillis subconfertis magnis albo-tomentosis, vix 
setulosis; aculeorum 1-4 robustioram summo valido angulato fuscato porrecto, ceteris debilioribus pallidioribus patuli 
seu tadiantibus; aculeis inferioribus 2-6 gracilibus albis radiantibus; floribus minoribus; bacca ovata vix spin inulosa, 
umbilico infundibuliformi ; seminibus paucis magnis subregularibus. 
