wv 
459 
Western United States—Continued. 
Joints obovate. 
Spines straw-colored. 
lindheimeri (7), chlorotica (12), procumbens (18), angustata (20). 
Spines white or whitish (sometimes dusky at base or apex). 
Spines mostly 1 to 3. 
Longest spines not exceeding 3.5 cm. 
dulcis (8), occidentalis (9), mesacantha (31), stenochila (36), 
macrorhiza (87), 
Longest spines about 5 cm. 
angustata (20), filipendula (30). 
Spines mostly 4 to 10, 
Longest spines not exceeding 3.5 em. 
albispina (53), arenaria (59), 
Longest spines 6 to 10 em. 
tortispina (26), tenuispina (28), hystricina (49). 
Spines reddish or brown to black. 
Spines mostly 1 to 3. 
Longest spines not exceeding 3.5 em. 
lindheimeri (7), greenii (38), vaseyi (40), fusco-atra (41). 
Longest spines 5 to 7.5 cm. 
procumbens (18), phwacantha (23), eamanchica (25). 
Spines mostly 4 to 15. 
Longest spines not exceeding 3.5 em, 
strigil (2), arenaria (59). 
Longest spines about 5 em. 
procumbens (18), platyearpa (51), borealis (52). 
Longest spines 6 to 10 em. 
phwacantha (23), camanchica (25), hystricina (49). 
II. Joints cylindraceous, more or less tuberculate.—Cylindropuntias. 
* Spineless. 
ramosissima (100), rotundifolia (101). 
** Spiny. 
+ Spines without sheaths. 
Longest spines not exceeding 1 to 3.5 em. 
bulbispina (62), parryi (63), clavata (64), pulehella (65), 
Longest spines 5 to 6 cm. 
grahami (66), emoryi (67), schottii (68), invicta (70). 
+--+ Spines with sheaths. 
Mexico. 
tunicata (72), imbricata (89), thurberi (93). 
Lower California. 
clavellina (71), ciribe (73), molesta (91), calmalliana (92), 
Southwestern United States. 
Spines mostly 5 to 20. 
Fruit spiny. 
Longest spines not exceeding 2 to 2.5 cm. 
echinocarpa (75), serpentina (79). 
Longest spines 3 to 3.5 cm. 
davisii (74), bernardina (80), acanthocarpa (94) 
Fruit not spiny. 
Longest spines not exceeding 1.5 to 2.5 cm, 
bigelovii (85), whipplei (86), versicolor (90). 
Longest spines 3 to 3.5 cm. 
prolifera (82), fulgida (83), arborescens (88). 
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