UNITED STATES AND MEXICAN BOUNDARY. 
and longer than all the others, and flattened or even channelled, pale-yellowish, often purplish 
at base, flexuous; more or less hooked, sometimes straight, 2-4 inches long. Flowers 2-3 
inches long, yellow, apparently without the scarlet base of the petals, which I always find in 
both the allied species, externally greenish ; fruit oval, 8-9 lines long, with 7-12 scales ; green 
when ripe; seeds 0.4-0.6 line long. Dr. Poselger describes another form under the name of 
E. setispinus 3. robustus, which is said to have all four central, and often thesthree lower radial 
spines, also, more or less hooked. The seed which he h nt to me leaves no doubt in 
my mind that itis a form of E. sinuatus. In my specimens only the lateral spines sometimes 
ave flexuous, or hooked, or almost curled. 
6. E. LonarHamatus, Galeotti: subglobosus seu demum ovatus, lete-viridis, costis 13-17 
sepe obliquis tuberculato-interruptis latioribus obtusis; tuberculis ovatis supra brevissime 
sulcatis ; areolis ovatis seu suborbiculatis distantibus ; aculeis junioribus demum totis cinereis ; 
radialibus 8-12 rectis curvatis flexuosisve patulis, superioribus gracilioribus pallidioribus, infimo 
brevi, lateralibus longioribus subannulatis; aculeis centralibus 4 (1-4 superioribus adventitiis 
subinde adjectis) angulatis compressis annulatis, quorum superiores recti seu curvati seu con- 
torti sursum versi, infimus robustiorplerumque longissimus seepe flexuosus plus minus uncinatus 
porrectus vel deflexus; floribus ab areola aculeifera vix sejunctis infundibuliformibus, limbo 
patulo ; ovario ovato; sepalis. scarioso-marginatis ciliatis, inferioribus 30-60 squamiformibus 
reniformibus, mediis 10-20 obovato-spathulatis, interioribus 15-20 demum oblongo-obovatis 
obtusis cuspidatis ; petalis 20-30 oblanceolatis obtusis vel retusis denticulatis cuspidatis seu 
muc onatis sulphureis ima basi coccineis et sepius dorso rubellis ; stigmatibus 15-18 obtusis 
sulphureis ‘pa ulis\;.bacca ovata squamosa viridi; seminibus globoso-obovatis hilo ovato sub- 
basilari oblique excisis scrobiculatis lucidis, (Tab. XXI—XXIV.) | 
Var. a, crassisprnus.. E, flexispinus, Z. in Wisl. Rep. non Salm. 
Var. 8. GRACILISPINUS: aculeis gracilioribus 16-20; exterioribus 12-14 
elongato hamato, E: hamatocanthus, Muehlenpf. 
Var. y. BREVISPINUS : aculeis gracilioribus, radialibus 8-11, centralibus 4 teretibus cum infimo 
hamato radiales vix superantibus. ere 
Along the middle course of the Rio Grande and near the Pecos and San Pedro rivers, on the 
mountains of the Limpia, and near Presidio del Norte, and southward into Mexico, but not as 
far west as E] Paso, Wright, Bigelow: fl. Juneand J uly.—Heads } to 2 feet high, but flowering 
often when not more than two inches high. , Ribs usually 13; areole roundish in younger, 
more elongated in older specimens, often only 6-10 lines, but in’ vigorous plants 1-1} inch 
apart. Spines glabrous, or only the lower central one scabrous-pubescent ; lateral spines whitish, 
all the others purplish or variegated , With paler semitransparent tips. 
those which occur in our t 
, centralibus 4-8, infimo 
The forms f. and y. are 
temitory ; they differ in the length and number of spines, but not at 
all in flower and fruit. — Var. 8. the lower and upper radial spines are 1-3 inches, the 
lateral ones 2-3} inches long, upper central spines 2-5, and lower one 3-64 inches long. 
Var. % is perhaps the young plant, as these plants often flower when yet quite young, and before 
the character of the mature plant is yet fully developed. This in a very marked degree is the 
case with /. uncinatus, var., which begins to bloom while the central spine is yet quite short 
and terete. Lower radial spines 4-1} inch, upper ones 14~2 inches long, lateral ones 
13-1} inch, and central spines all 1}-2 inches long. Flowers form a groove just above the 
spines, separated from the spiniferous areola by 2-5 obtuse cylindric glandular bodies which 
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