INTRODUCTION TO THE REPORTS ON INSULAR FLORAS. 



21 



Canary Islands and Madeira. 



The Composite number about 150 species, whereof half are endemic. Bentham (loc. 

 cit., p. 563) says : — " The insular tendency to a more shrubby form than their continental 

 congeners or allies is also exhibited in Allagopappus, Viercea, Gonospermum, Chrysan- 

 themum, Senecio, and Sonchus ; but there is nothing of the arborescent or highly differen- 

 tiated character of the Petrobium of St Helena, of the Dendroseris and others of Juan 

 Fernandez, or of the Fitchia of the South Sea Islands." 



In this comparison, as in that concerning the Galapagos Compositae, Bentham seems 

 to have entertained an exasperated idea of the stature of the St Helena and Juan 

 Fernandez woody members of the order. As already mentioned, Bertero gives the height 

 of three of the larger species of Dendroseris as ten to fifteen feet. Two or three of the 

 Madeiran and Canary Island species of Sonchus, a genus of the same suborder as 

 Dendroseris, attain to about the same size. Thus Sonchus fruticosus, Linn, f., is 

 described by Lowe (Manual of the Flora of Madeira, i. p. 552) in the following words : — 

 " Almost subarborescent, and gigantic in all its parts, being from four or five to ten or 

 twelve feet high, with a trunk often as thick as the arm, and the ultimate branches as 

 thick as the forefinger, ending in large spreading or radiating tufts of leaves." The habit 

 of the species of Dendroseris represented in Guillemin's Archives de Botanique, i. t. 9, from 

 Gay's drawings, executed in Juan Fernandez, agrees exactly with the foregoing description. 

 Sonchus arboreus, DC, a Canary Island species, attains similar dimensions ; and Senecio 

 kleinia, Schulz Bip., from the same group, equally deserves the appellation " arboreous ; " 

 while several of these find their counterparts among the dwarfer species of Dendro- 

 seris, &c. Finally, Centaurea arborea, Webb, is described as " Frutex speciosissimus, 

 12-pedalis." 



St Helena. 



In regard to size, if not in height, a few of the larger of the arboreous Composite of 

 St Helena considerably surpass those of the islands already considered ; although, as we 



(BOT. CHALL. EXP. — INTRODUCTION. — 18S5.) 4 



