190 



THE CACTACEAE. 



10. Hylocereus monacanthus (Lemaire). 



Cereus monacanthus Lemaire, Hort. Univ. 6: 60. 1845. 

 Steins green, 3-angled, the margins undulate; areoles remote, about 3 cm. apart, tomentose; 

 spines usually single, sometimes 2, rigid, much swollen at base; flowers funnelform, large, 28 cm. 

 long, 17 cm. broad; ovary and tube covered with large scales; outer perianth-segments narrow, 

 greenish; inner perianth-segments oblong-ovate; filaments numerous, about 200, 8 to 9 cm. long, 

 white but rose-colored at base; style thick, exserted, yellow; stigma-lobes numerous, spreading. 



Type locality: Colombia. 



Distribution: Colombia and Panama. 



This species was first introduced by Cels and published in 1845. It was again intro- 

 duced by Werckle in 1905 and fully described by Weingart in 191 1. Both Dr. Weber and 

 Dr. Schumann considered it to be a variety of Cereus martinii. 



A flower observed at the New York Botanical Garden September 6, 1918, and a plant 

 brought by Dr. M. A. Howe from the Urava Islands in 1912, showed 2-forked stigma-lobes, 

 the forks 2 to 3 mm. long; other flowers, previously observed, showed simple stigma-lobes. 



Plate xxix shows a branch of the plant collected by Dr. Howe, on Urava Island, Bay 

 of Panama, in 1912, which flowered in the New York Botanical Garden in 1915. 











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Fig. 267. — Hylocereus stenopterus. 



11. Hylocereus stenopterus (Weber) Britton and Rose, Contr. U. S. Nat. Herb. 12: 429. 1909. 

 Cereus stenopterus Weber, Bull. Mus. Hist. Nat. Paris 8: 458. 1902. 

 A weak vine, not rooting freely from the sides, at least in cultivation, the joints 4 cm. broad, 

 light green in color, not glaucous; ribs 3, thin; areoles slightly elevated; spines 1 to 3, small, yellow; 

 flower 10 to 12 cm. long, opening at night, closing very early (completely closed at 9 a. m.); tube 

 short, about 2 cm. long; perianth-segments all similar, reddish purple, linear, about 7 cm. long; 

 stamens short, exserted; style white, thick, much exserted; stigma-lobes white, when closed form- 

 ing an ovoid acuminate cluster ; scales on ovary and flower-tube orbicular or the upper ones narrowly 

 ovate, green, with purple margins. 



Type locality: Vallee de Tuis, Costa Rica. 



Distribution: Costa Rica, Central America. 



This species is common in Costa Rica, and in recent years has been widely distributed 

 by several Costa Rican collectors; it grows well under glass, and flowers frequently. It is 

 the only Hylocereus in cultivation with red flowers except H. extensus. 



Plate xxvn, figure 3, is from a plant obtained by Mr. William R. Maxon in San Jose, 

 Costa Rica, in 1906, which flowered at the New York Botanical Garden. Figure 267 is 

 from a photograph of a specimen which flowered in Washington from specimens received 

 from the New York Botanical Garden in 1910 (No. 22197). 



