108 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Ser. 



ters by which they could be recognized. As there is evidently 

 but one species of Cereus on this island, it seems necessary to 

 reduce them to one, C. galapagensis, which can be recognized 

 by the following characters. Arborescent, often 8 or more 

 meters in height; trunk cylindrical, 15-30 cm. in diameter; 

 stems diverging; articulations short, robust, obtusely rounded 

 at the extremities, with deep indentations at the points of union 

 of the articulations, 18-angled, costae prominent. Flowers 

 chocolate brown with yellow stripes. Outer petals broadly 

 spatulate cochleariform, 2.3 cm. long, 2 cm. broad at tip, mu- 

 cronate, margins entire to denticulate; inner petals cuneate 

 mucronate, 2.4 cm. long, 8 mm. broad, margins dentate. Stig- 

 mas 11, fruit oval rounded, resembling a large prune, as de- 

 scribed by Weber, 1. c. A flower from a specimen of this 

 species from Chatham Isl. shows considerable divergence from 

 the above description in that the outer petals are narrowly spat- 

 ulate, 3.1 cm. long, 8 mm. broad, abruptly acuminate, somewhat 

 cochleariform; inner petals narrowly lanceolate, 3.2 cm. long, 5 

 mm. broad, acuminate, margins irregularly dentate. Excellent 

 photographs of this species were published by Agassiz ( 1 ) , PI. 

 XVI and XX, where specimens from both Charles and 

 Chatham Ids. are shown. 



C. nesioticus K. Sch. in Rob. (1), 179. — Abingdon Isl.: 

 fairly abundant on old cinder beds along the south side of the 

 island. No other vegetation occurs near where the specimens 

 were taken, (no. 2092). Albemarle Isl.: Black Bight, 

 Snodgrass and Heller; Christopher Point, Snodgrass and 

 Heller; Elizabeth Bay, Snodgrass and Heller. Chatham Isl. : 

 Sappho Cove, reported by E. S. King, one of the members of 

 the expedition. James Isl. : James Bay, common on recent 

 lava south of the bay and along the south side of the island. 

 Narborough Isl. : northeast side, common on recent lava (no. 

 2093) ; south side, occurs to above 500 ft. ace. to /. 5. Hunter. 

 Tower Isl. : a few isolated bunches of this species were found 

 on a small deposit of cinders around a blow-hole in the interior 

 of the island (no. 2094). 



This species is always found in the most sterile and desert 

 situations and never occurs where there is much if any other 

 vegetation. On both Narborough and James Islands it was 

 found growing abundantly on beds of lava apparently as fresh 



