HARRISIA. 



147 



about i cm. high, separated by broad, rounded intervals; areoles rather close together, i cm. apart 

 or less, bearing brown felt; spines various as to length, sometimes only i cm. long, sometimes 8 cm. 

 long, usually slender, sometimes bristle-like, often 10 or more at an areole; flowers various in size, 

 5 to 1 1 cm. long, "chocolate-brown with yellow stripes"; outer perianth-segments spatulate, 2 to 3 

 cm. long; inner perianth-segments linear, about 2.4 to 3 cm. long; ovary terete, scaly; scales few, 

 i to 1.5 mm. long, ovate, acute; stigma-lobes n; flower-tube about twice as long as the segments; 

 fruit greenish, short-oblong, 5 cm. long, 4 cm. in diameter, with a thin tough rind, palatable. 



Type locality: St. Charles Island, Galapagos. 



Distribution: Various islands of the Galapagos group. 



This species and the other cacti of the Galapagos Islands were discovered by Charles 

 Darwin in 1835. He associated this species with Cereus perumanus, which it resembles 

 only in its large cylindric trunk. The various collectors who have since visited these 

 islands have noted this striking plant, but little material has been collected and even to-day 

 our knowledge is very limited. 



W. Betting Hemsley has written most interestingly of the cactus flora of the islands 

 (Gard. Chron. III. 24: 265, 266. 1898; 27: 177, 178. 1900). 



Mr. Alban Stewart, who made extensive collections in the Galapagos Islands in 1905 

 and 1906, discusses the cacti in considerable detail (Proc. Calif. Acad. Sci. IV. i : 107 to 1 15). 

 He recognizes two columnar arborescent species under the names Cereus galapagensis 

 Weber and Cereus sclerocarpus Schumann, and indicates that they maybe distinguished by 

 habit characters, but remarks particularly on the great variability of the flowers of both. 



Illustrations: Proc. Calif. Acad. Sci. 

 IV. i : pi. 6, 1 6, as Cereus sclerocarpus ; Gard. 

 Chron. III. 27: 185. f. 61, as Cereus sp.; 

 Wolf, Geographia y Geologia del Ecuador 

 f. 41, pi. ii ; Bull. Mus. Comp. Zool. 23: pi. 

 16, 20. 



Figure 2 1 2 is from a photograph of the 

 plant in its natural habitat on Charles 

 Island, Galapagos, contributed by the 

 United States Fish Commission; figures 

 213 and 214 show flowers drawn from an 

 herbarium specimen in the collection of the 

 California Academy of Sciences, collected 

 by Alban Stewart (No. 2097) m I 95 an d 



1906. FIGS. 213 and 214. Flowers of J. galapagensis. Xo.6. 



26. HARRISIA Britton, Bull. Torr. Club 35: 561. 1908. 

 Eriocereus Riccobono, Boll. R. Ort. Bot. Palermo 8: 238. 1909. 



Night-flowering cacti with slender, branched stems, the branches fluted or angled, each areole 

 with several acicular spines; flowers borne singly at areoles near the ends of the branches, funnel- 

 form, large, with a cylindric, scaly tube as long as the limb or longer; buds globose, ovoid or obovoid, 

 the scales subtending areoles which bear tufts of long or short hairs, persistent or sometimes deciduous 

 as the flower expands; outer perianth-segments mostly pink or greenish, linear to lanceolate; inner 

 perianth-segments white or pinkish; stamens shorter than the perianth; ovary and young fruit 

 tubercled; style somewhat longer than the stamens; fruit globose to obovoid-globose, spineless or 

 spiny, but with mostly deciduous scales, the corolla withering-persistent; seeds numerous, small. 



The genus is named in honor of William Harris, superintendent of Public Gardens and 

 Plantations of Jamaica, distinguished for his contributions to the knowledge of the flora of 

 that island. 



We recognize 17 species, distributed from Florida and the Bahamas and the Greater 

 Antilles to Argentina. The type species is Cereus gracilis Miller. 



