BOTANY OF PERNANDO IfOEOKHA. 39 



CACTACEJE. 



Ceeetjs insulaeis, Hemsl. Bot. 'Chall.'' Exp., Atlantic Isles, 

 p. 16, t. xiv. 



This was described and figured from material brought by the 

 ' Challenger ' expedition ; but as the description is incomplete in 

 some respects and inaccurate in others, owing to deficiency of 

 material, I append an emended description. 



Planta valida, ramis 6-12-pedalibus, erectis vel peudulis, api- 

 cibus recurvis, 1-1| uncias diametro, costis obtusis saepis- 

 sime 7, 5 unciam altis continuis, areolae pulvinatse, 5 unciam 

 dissita lanugine albo parvo ; spinse radiatse ochreae 12-15, in- 

 aequales pungentes, longiores, unciam longae. Flores nocturni, 

 5-6 uncias longi, 2 uncias in diametro, erecti, amoenissime odori, 

 ochroleuci. Calycis tubus 3-uncialis, vix 5 unciam in diametro, 

 viridis, squamis paucis rufescentibus lanceolatis acuminatis. 

 Sepala lanceolata acuta pauciseriata, rubro-viridia, lougiora 

 uncialia. Petala ochroleuca ferme alba tenuia late lanceolata 

 obtusa, apicibus minute fimbriatis, quam sepala paullo breviora. 

 Stamina erecta copiosa, quam petala breviora ; interiora multi 

 breviora, filamenta alba apiee attenuata; antherae oblongae, g- 

 unciales, flavi. Stylus validulus 5-uncialis. Stigmata 5-unciam 

 longa, 7-11, subacuta, viridia. Ovarium viride J-unciale multi- 

 ovulata. Fructus magnus 4 uncias longiis, 3 uncias latus, 

 oblongus obtusus, kermesinus, albo-pruinosus. Semina parva 

 nigra. 



This is very common on Eat Island, Booby Isle, San Jose, 

 Sella Griueta, as well as on the main island, and is one of the most 

 conspicuous plants. It frequently hangs down over the cliffs, 

 quite covering them ; but also forms thickets in open dry spots, 

 and also grows even in the dense thickets of the Sapate. Here 

 thei'e was a woodland form, which differed in some respects from 

 the common type, and may be the Cactus quadrmigularis of 

 "Webster. It has more slender dark green stems less than an inch 

 in diameter, with five ridges only and very short weak thorns, the 

 largest of which were only half an inch long. No signs of fruit 

 or flower were found on this form ; but I have little doubt that 

 it is a wood form of the common species. On two occasions 

 fasciated branches were found in the dense thicket at the summit 

 of Tangle Eock. 



