2~>s Cactaceae 



sessile, terminal or lateral, perfect, regular and showy. 

 Calyx-tube adnate to the ovary, its Limb many-lobed or 

 with distinct sepals. Petals numerous in several rows. 

 mostly distinct. Stamens numerous, inserted on the 

 throat of the calyx, with filiform filaments and small 

 anthers. Ovary 1-celled, with numerous anatropous 

 ovules borne on several parietal placentae. Style ter- 

 minal, elongated ; stigmas numerous. Fruit a berry, 

 mostly fleshy. Seeds smooth or tubercled, the testa usu- 

 ally crustaceous or bony ; endosperm scanty or copious. 



Spines never barbed: flower-bearing areola? distinct from those bearing the 



spines. 1. Cereus. 



Spines minutely barbed; flowers from the same areohe as the spines. 



2. Opuntia. 



1. CEREUS Baworth. 



Stems oval or cylindric, with the spine-bearing areolae 

 on vertical ribs. Flowers from the older or fully de- 

 veloped parts of the plant bursting through the epider- 

 mis just above the bunches of spines, usually about as 

 long as broad, sometimes elongated. Scales of the ovary 

 distinct, with naked or woolly axils, or almost obsolete 

 and the axils spiny. Berry succulent, covered with 

 spines or scales, or nearly naked. Seeds black ; endo- 

 sperm none; embryo straight or curved. 



1. C. Emoryi Engelm. Stems spreading, branching from the 

 base, cylindric, with 16-20 ribs, closely set with prominent hemi- 

 spheric areolae, bearing numerous thin straight yellow interlocked 

 spines; radials 40-50, very slender; central solitary, stouter and 

 much longer; flowers greenish yellow, 3-6 cm. broad, crowded on 

 one side near the end of the branches; fruit globose, very spiny, 

 3.5 cm. in diameter; seeds obovate, acutely keeled, shining and 

 minutely tuberculate, 2.4-2.8 mm. long. 



Said to occur from San Diego to the Salinas Valley, but we have not seen 

 it north of San Diego. 



2. OPUNTIA Mill. 



Plant- with flat or Cylindric more or less tuberculate 



joints and COnspicUOUB hut caducous leaves. These each 



