Colorado Agricultural College 
Prickly Pear, Many-spined 
Opuntia {Opuntia polyacantha 
Haw., Opuntia missouriensis 
DC.) (Fig. 103). — Seeds white 
with a grayish area on each side, 
flattened, faceted, irregular with 
angles and depressions through- 
out and a distinct notch or slit 
at one side, as though the 
extremities had been pressed 
tightly together; a distinct band- 
like margin, .6-1 mm. wide, com- 
pletely encircles the seed ; seeds 
4-6 mm. across each face. I-Mg. 103 . Prickly Pear (Opuntia pol- 
ycantha) x PC 
22 . EVENING PRIMROSE FAMILY 
(Onagraceae) 
Fruit a capsule or nut-like; seeds with the micropyle next tin 
hilum ; seeds small, mostly without eiulospeim. 
Key to CJeiiera 
Seeds enclosed in a nutlet 
Seeds not enclosed in a nutlet; seeds prismatic, angled 
1 . . Gaura I 
2. .Ocnoihcri 
3. Mallow 
(Malva {Toarn.) L.) 
Irnil as in Malvastrum; nutlets often splitting open at maturity; nutlets 
and seeds circualr in outline, flattened. 
Common or Low Mallow, Ciieesfr 
(Malva rotundifolia L.) (Fig. 1U2). — 
Nutlets and seeds of the same color as 
Malvastnmi coecineum; seeds flattened^ 
notched on one side, circular in outline, 
1.2-1. 5 mm. wide, smooth; nutlets smooth 
or very siglhtly wrinkled, thin and seldom 
Fig. 102 . Common Maiiov/ covering the entire seed. 
(Malva rotundifolia). Nutlet 
(left), seed (right), x 15. 
21. CACTUS FAMILY 
(Cactaceae) 
Fruit a fleshy or sometimes dry berry; seeds usually hard and 
brittle in texture, smooth, with faceted surfaces; endosperm little 
or abundant. 
Prickly Pear, Indian Fig, Cholla 
(Opuntia, Mill.) 
Berry often pear-shaped or nearly so, often spiny, fleshy or sometimes 
dry; seeds flattened, oval to nearly circular in outline; embryo curved around 
the endosperm. 
