78 
THE CACTACEAE. 
Key to Genera— continued. 
Axils of flower-scales naked. 
Tube of flower longer than limb, its scales not fimbriate; spines all 
straight. 
Tube of flower not longer than limb, its scales fimbriate; central spine 
hooked. 
CC. Flowers mostly campanulate, at least not long and slender. (See 
Leuchtenbergia and some species of Gymnocalycium). 
D. Areoles not arranged on ribs. 
Tubercles short, imbricated, much as in Ariocarpus . 
Tubercles much elongated, slender, finger-like. 
DD. Areoles arranged on definite ribs. 
E. Scales of ovary and perianth-tube entire (except in some large 
species of Ferocactus). 
F. Axils of scales on ovary and fruit naked. 
Ribs usually continuous, rarely if ever tubercled; flowers 
with scarcely any tube. 
Ribs usually numerous, much compressed and thin. .. 
Ribs not so numerous, usually thick. 
Ribs usually broad, tubercled; flowers with a short but 
definite tube. 
Spines or most of them acicular; flowers pimple; seeds 
muricate. 
Spines stout, mostly subulate; flowers white, yellow, 
or pink; seeds tuberculate. 
FF. Axils of scales on ovary hairy, woolly or setose. 
Ovary-scales many, their axils woolly. 
Axils of scales on flower-tube neither bristly nor spiny. 
Ribs several to many; plants very spiny. 
Fruit permanently woolly, nearly dry, dehiscent 
by a terminal pore. 
Fruit not so woolly, bursting irregularly, some¬ 
what fleshy. 
Ribs few, broad; plants mostly spineless. 
Axils of scales on flower-tube usually bristly or spiny 
as well as woolly. 
Top of fruit spinose; seeds pitted. 
Top of fruit not spinose; seeds not pitted. 
Seeds not shell-like; plants mostly large. 
Spines straight or rarely curved; seeds with 
truncate base. 
Spines acicular, one of centrals strongly hooked; 
seeds minute. 
Seeds shell-like; plants very small. 
Ovary-scales few, their axils with tufts of short hairs. 
Fruit a berry; spines all straight. 
Fruit dry, dehiscent by a basal pore; some spines hooked. 
EE. Scales of ovary and perianth-tube fimbriate-lacerate; plant 
small; flowers nearly rotate. 
11. Matucana (p. 102) 
12. Hamatocactus (p. 104) 
13. Strombocactus (p. 106) 
14. Leuchtenbergia (p. 107) 
15. Echinofossulocactus (p. 109) 
16. Ferocactus (p. 123) 
17. Echinomastus (p. 147) 
18. Gymnocalycium (p. 152) 
19. Echinocactus (p. 166) 
20. Homalocephala (p. 181) 
21. Astrophytum (p. 182) 
22. Eriosyce (p. 186) 
23. Malacocarpus (p. 187) 
24. Hickenia (p. 207) 
25. Frailea (p. 208) 
26. Mila (p. 211) 
27. Sclerocactus (p. 212) 
28. Utahia (p. 215) 
1. DENMOZA gen. nov. 
Plant cylindric, often elongated, the numerous, parallel straight ribs slightly undulate; spines 
in clusters at the areoles; flowers arising from the top of the plant, zygomorphic, scarlet, with a slen¬ 
der throat and very narrow limb; tube proper very short, its mouth closed with a mass of white wool; 
inner surface of the elongated throat covered with stamens; filaments and style long-exserted; ovary 
and tube bearing numerous scales, their axils filled with silky hairs; fruit globular, dry, splitting 
down from the top; seeds black, dull, pitted. 
Type species: Echinocactus rhodacanthus Salm-Dyck. 
The generic name is an anagram of Mendoza, the province in Argentina, where the 
plant is native. Only one species is known. 
The peculiar mass of white wool near the base of the flower-tube on the inside is not 
known, as far as our observation goes, in any other cactus, except in two species of Lobivia 
of doubtful relationship, described by Dr. Spegazzini as species of Echinocactus, and in E. 
spiniflorus, all of which are otherwise quite different from Denmoza. 
The genus here segregated was considered by Schumann as a species of Echinopsis 
but it has also been referred to Cereus, Echinocactus, Cleistocactus, and Pilocereus. In its 
