﻿Cook : Flora of the Canary Islands 355 



less Senecio spinos?ts, which is as uncomfortable to handle as a sea 

 urchin, and when the stems are broken, has a most disagree- 

 able odor. It is very frequently half hidden in dense coils of 

 Cuscitta episonchnm, peculiar to the island, a humble relative of the 

 beautiful shrubby Convolvulaceae which adorn the hillsides. Ten 

 of the seventeen Convolvulaceae of the islands are not found else- 

 where, and five of these peculiar species are fruticose. 



Other Compositae of the tufa are species of Chrysanthemum, 

 Picris, Urospcrmum, Senecfa, etc. It seems worthy of remark that 

 many of these, as of the other species of the desert lands, of what- 

 ever family (Euphorbiaceae, Compositae, Umbelliferae, Plumbag- 

 inaceae, Labiatae) grow in dense clumps, probably as a means 01 

 increased resistance to transpiration in addition to such other 

 adaptations as fleshy or much reduced foliage, hoariness or coria- 

 ceous texture. The contrast between the shore Senecios and the 

 fleshy Senecio Kleinia, which is common in the ravines, makes one 

 question the present status of our systems of classification. The 

 Compositae are altogether well represented by seventy five genera, 

 including about sixty five peculiar species. Eupatorium agera- 

 toides, not reported by Webb and Berthelot, is very common in the 

 barrancos of Firgas and Tafira. Thistles of many genera are a 

 conspicuous and beautiful feature in all sorts of localities. 



The genus Statice has nine species, all peculiar to the islands, 

 found in rr.nl, r and maritime localities and most of them v 



ition, e. g., S. papillata is reported only fi 



e rocky islets Graciosa and Alegranza ; S. brassicacj 



ery 



ited 

 littl 



from Gomera. 



Even more highly differentiated is the Labiate genus Micro- 

 meria— represented by seventeen species, all but one peculiar to 

 th e Canaries and that one found elsewhere only on Madeira and 

 P °rto Santo. These plants grow in arid places among rocks and 

 °n hillsides everywhere— the shore forms assuming the character- 

 ise dense clump growth. Salvia Canadensis is another intcr- 

 est 'nk r member of this family. It is widely spread on the islands 

 an d we have found, besides the ordinary merely hirsute form, an- 

 oth cr with densely white-woolly leaves which may be a distinct 

 ^cies and also a third form with pure white flowers instead of 

 the ^ual pink-purple ones. 



