The; cactaceai?. 



161 a. Opuntia zebrina Small, Journ. N. Y. Bot. Gard. 20: 35. 1919. (See page 155, ante.) 



Plant erect, more or less branched throughout, fully i meter tall or less, the roots fibrous, 

 joints oval or obovate, thickish, mostly i to 2 dm. long, deep green, sometimes obscurely glau- 

 cous; leaves ovoid, 2 to 3 mm. long, bright green; areloes scattered, some of them, usually the lower 

 ones, unarmed, the upper ones irregularly armed; spines slender, solitary or 2, 3, or 4, together, 

 red-brown, finely banded, nearly terete, closely spirally twisted; flowers few on a joint, or soli- 

 tary ; sepals deltoid to deltoid-reniform or nearly reniform ; corolla yellow, rotate, 6 to 7 cm. wide ; 

 petals rather numerous, the inner ones broadly obovate, undulate, minutely mucronate or notched 

 at the apex; berries obovoid, not constricted at the base, 3.5 to 4.5 cm. long, red-purple; seeds 

 many, 6 to 7 mm. in diameter. 



O. zebrina. X0.5. 



Fig. 295. — Opuntia zebrina. 



Type locality: Middle Cape Sable, Florida. 



Distribution: Coastal sand-dunes. Cape Sable, Florida, and the lower 

 Florida Keys. 



The plant was first discovered by Dr. Britton on Boot Key, Florida, 

 in 1909, and this is the most northern locality yet known for it. The spe- 

 cies is interesting not only from its strikingly banded spines but also as 

 being the only known member of the series Elatiores growing wild within 

 the United States. In habit it resembles 0. dillenii, and on Key West the 

 two species were observed growing close together. 



Illustration: Journ. N. Y. Bot. Gard. 20 : pi. 226. 



Figure 295 is from a photograph of the plant on Cape Sable, Florida, in cultivation at 

 Buena Vista, Miami, Florida; figure 296 shows a fruit collected by Dr. Rose on Key West, 

 Florida, in 1918. 



173 a. Opuntia keyensis Britton in Small, Journ. N. Y. Bot. Gard. 20: 31. 1919. (See p. 162, ante.) 



Plant erect, much branched, sometimes forming clumps 3 meters tall, with long fibrous roots ; 

 joints elliptic, oval, obovate, or spatulate, thick, i to 3 dm. long, bright green; leaves ovoid, 2 to 3 

 mm. long, green; areoles rather conspicuous, often relatively large and prominent, apparently 

 unarmed ; spines stout, 4 to 13 together, very short, mostly hidden in the bristles; at first pink, 

 at maturity salmon-colored, sHghtly flattened; flowers soHtary or 2 or 3 on a joint; sepals deltoid 

 to subreniform, acute or acutish; corolla salmon-colored, cup-like, or short-campanulate, 3 to 3.5 cm. 

 wide; petals rather few, thinner ones broadly obovate or orbicular-obovate, undulate, scarcely, if 

 at all, mucronate; berries obovoid, 4 to 6 cm. long, purple; seeds numerous. 



