DESCRIPTIONS AND ILLUSTRATIONS OF PLANTS OF THE 



CACTUS FAMILY. 



Tribe 3. CEREEAE. 



Subtribe 3. ECHINOCEREANAE. 



Mostly low, simple or cespitose, terrestrial cacti, the stems 1 -jointed or rarely few- 

 jointed, ribbed; areoles borne on the ribs and spiniferous or rarely spineless; flowers always 

 solitary at lateral* areoles, funnelform to campanulate ; perianth-segments few to many ; 

 fruit smooth or spiny, with few exceptions fleshy and indehiscent or splitting on one side; 

 seeds mostly black. 



We recognize 6 genera, all South American except Echinocereus. 



This subtribe, while somewhat uniform in its low, usually one-jointed stems, shows 

 great variability in its flowers. Both Chamacccreus and Austrocactus are taken from Cereus 

 of previous authors ; Echinocereus has often been considered as a subgenus of Cereus. Echi- 

 nopsis has usually been treated as a distinct genus related to Cereus, Bentham and Hooker, 

 however, treating it as a subgenus of Cereus; in our opinion, it approaches Trichocereus 

 in its flowers, but in habit resembles various genera in the Echinocactanae . Lobivia is 

 segregated from Echinopsis. Rebutia has sometimes been recognized as a genus, but its 

 species have usually been referred to Echinocactus or Echinopsis. The subtribe is nearest 

 the Cereanae, but is also related to the Echinocactanae. 



Key to Genera. 



Ovary and fruit bearing clusters of spines at areoles. 



Stigma-lobes always green; spines all straight i. Echinocereus (p. 3) 



Stigma-lobes red; some spines hooked 2. Austrocactus (p. 44) 



Ovary and fruit not spiny. 



Spines on tubercles as in Coryphantha; plants globular 3. Rebutia (p. 45) 



Spines on ribs. 



Plants very small, creeping, forming low clumps 4. Chamaecereus (p. 48) 



Plants mostly large, solitary or cespitose. 



Flower short-funnelform to campanulate; tube short 5. Lobivia (p. 49) 



Flower long-funnelform; tube elongated 6. Echinopsis (p. 60) 



1. ECHINOCEREUS Engelmann in Wislizenus, Mem. Tour North. Mex. 91. 1848. 



Plants always low, perennial, erect or prostrate, sometimes pendent over rocks and cliffs, 

 single or cespitose, globular to cylindric, prostrate or pendent if elongated ; spines of flowering and 

 sterile areoles similar; flowers usually large, but in some species small, diurnal, but in some species 

 not closing at night; perianth campanulate to short-funnelform, scarlet, crimson, purple or rarely 

 yellow, the tube and ovary always spiny; stigma-lobes always green; fruit more or less colored, 

 thin-skinned, often edible, spiny, the spines easily detached when mature; seeds black, tuberculate. 



Type species: Echinocereus viridiflorus Engelmann. 



The first part of the generic name is from ex^vos hedgehog, doubtless given on account 

 of the spiny fruit in which Echinocereus is conspicuously different from the true Cereus. 



We recognize 60 species. Professor Schumann admitted 39 species in his monograph 

 of 1898, while more than 190 species and varieties have been proposed by other authors. 



The genus is confined to the western United States and Mexico. It extends as far 

 east as central Texas, Oklahoma, and Kansas, north to Wyoming and Utah, west to the 

 deserts of southern California, the Pacific coast, and islands of lower California, and south 

 to the City of Mexico. 



Echinocereus has often been combined with Cereus. Engelmann, as well as Berger, 

 treated it as a subgenus of Cereus, but Schumann gave it generic rank. As we understand 

 the genus, it is not close to Cereus proper, but is much nearer to some of the other genera. 



*Echinocereus baileyi is described as producing flowers from the young growth and appearing terminal; this 

 habit has been observed in other species, but is inconstant. 



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