58 UNITED STATES AND MEXICAN BOUNDARY. 
—Stems 6-10 feet high ; joints 4-12 inches long, 4-3 inch thick, covered with ovate or rather 
rhombic tubercles. Spines much more numerous in this variety than in the original form, 
found by Dr. Bigelow farther north, 6-9 lines long. Flowers 14-14 inch wide, cup-shaped; 
seeds nearly 2 lines in diameter, larger than in the northern form, with a very sharply marked 
linear commissure. 
22, O. arporzscens, E. in Wisl. Rep.: caule arborescente erecto reticulato-lignoso ; ramis 
-verticillatis horizontaliter divergentibus seu pendulis ; articulis verticillatis plerumque ternis 
quaternisve cylindricis perviridibus; tuberculis elongatis cristatis; foliis teretibus elongatis 
patulis ; pulvillis ovatis pulvinatis breviter tomentosis vix setosis; aculeis 8-30 corneis seu 
fuscis stramineo-vaginatis undique stellato-porrectis, 1-8 interioribus longioribus laxius vagi- 
natis, centrali sub-deflexo, exterioribus debilioribus arcte vaginatis ; flore purpureo magno; 
ovarii subglobosi tuberculati pulvillis 20-25 breviter tomentosis setas minutas et aculeolos 
paucos erectos deciduos gerentibus ; sepalis tubi 8-13 obovatis obtusis medio virescentibus mar- 
gine purpureis ; petalis 1012 obovatis obtusis retusisve ; filamentis purpureis ; stigmatibus 8; 
bacea globosa seu hemispherica tuberculis prominentibus cristata late umbilicata inermi sub- 
sicca flava; seminibus regularibus anguste commissuratis ; cotyledonibus incumbentibus seu 
rare obliquis. (Tab. LXXV, fig. 16-17.) 
This species extends from the upper waters of the Arkansas and the Platte rivers deep into 
Mexico, and from the plains east of the Llano Estacado (200 miles east of the Pecos) to Zuii, 
150 miles west of the Rio Grande, about 15 degrees of latitude and 8 of longitude: fl. May 
and June.—North and east this species is only about 5 feet high, but further south it is said to 
' become 20 or 30 feet high. Even the old trunks continue greenish and spiny ; the massive lig- 
neous skeleton is always characterized by the elongated-rhombic meshes and the verticillate 
insertions of the branches ; in very old specimens the cavity of the tube and the meshes become 
almost obliterated by the filling in of ligneous layers. The roots are often somewhat tuberous 
by a swelling of the fibres. Joints 2-6 inches long, less than an inch in diameter ; tubercles 
compressed: cristate, elevated, 7-9 lines long; leaves 6-10 lines long, hardly a line in diam- 
eter; spines very variable in number and size ; sometimes we find only 8-12 spines, not half 
_ an inch long, so that the plant from a distance uppears spineless ; but more frequently 20-25, 
or even more spines occur, the longest middle ones deflexed, and 8-10, or rarely 12-14 lines 
in length, other spines spreading all around, 4-8 lines long. The beautiful purple flowers are 
23-3 inches in diameter, and often profusely cover the tree; the stigmata have a length of 3 or 
3} lines. The fruit is about an inch long in all dimensions ; umbilicus wider or narrower, shal- 
_ lower or deeper, according to the greater or smaller prominence of the upper tubercles of the 
fruit. Seeds ie4 lines in diameter, usually of a regular shape, with little or no beak; the 
omens distinct, and between 0.1 and 0.2 line broad ; cotyledons almost always regularly 
incumbent, rarely somewhat oblique. Sometimes 3 cotyledons are observed in the seeds of this 
species, as is also the case in many others. 
= 23. Q. Mamitiata, A. Schott in litt.: caule arborescente reticulato-lignoso divaricato-ramo- 
_fissimo; articulis ovato-eylindricis crassis abbreviatis retusis perviridibus ; tuberculis ovatis 
¢ ae -y: ‘ . “7 nil se ve . ° . . Pe 
: tamidis prominentibus ; foliis ovatis abbreviatis euspidatis ; pulvillis ovatis albo-tomentosis setas 
- brevissima u nt reg tibus ; aculeis 4— ili j j 
Seavissimas seu nullas gerentibus ; aculeis 4-6 gracilibus bievibus arcte vaginatis stramineis 
a" Aric , 2 . - “7 5 ? 
- ~plerisque deflexis ; flore parvo purpureo ; ovarii ovati pul 
: P Bia ge Rae oe tbe 
ek nei acid, - villi 18-24 pulvinatis albo-tomento- 
Rie sepalis pes Toa ate orbiculatis ; petalis 8 late obovatis abbreviatis; filamentis exterioribus 
