8 



(5.) Saxifraga portosanctaria Boiss. Related to 5. maderensis 

 Don., from Madeira, but perhaps even more closely to 6'. cuneata 

 Willd. from the Iberian Penninsula. 



(6.) Galium geminiflorum Lowe, a small annual closely related 

 to one described from the Grecian Archipelago. 



(7.) Limonium pyramidatum (Lowe, as Statice). So close to 

 L. ovalifolium (Poir.) O. Ktze. that Menezes treats it as a variety. 

 It is however the only Limonium in the archipelago, though 

 Statice maderensis (Lowe as Armeria) occurs in Madeira. 



Not one of these seven endemics could be suspected of belong- 

 ing to the really ancient flora, and all may be supposed to have 

 been derived from ancestors which came across the sea, the seeds 

 perhaps carried by birds. They may date from the Pleistocene, 

 or at the earliest Pliocene, I should suppose. 



The Azores have nearly 40 species of endemic vascular plants, 

 but not one of these belongs to any one of the genera represented 

 by the Porto Santo endemics. This may be explained by the 

 rare and accidental character of the introductions providing 

 the stock from which these plants developed. 



The three Desertas islands, in plain sight from Porto Santo, 

 have 138 species of vascular plants, with 113 dicotyledons, 20 

 monocotyledons (all grasses except a Car e.T and an Asphodeliis), 

 3 ferns and a Selaginella. Two of the ferns are the common 

 brake and maiden hair. The little flat island called Chao, the 

 northernmost of the group, has i endemic species, the grass 

 Lolium loliaceiim (Arthorchortus loliaceus Lowe, Lolium lowei 

 Menezes). The southern Deserta, called Bugio, is the only 

 known locality for Chrysanthemum (Argyranthemiim) haema- 

 tomma Lowe. Thus the two endemics of the Desertas are of 

 different genera from those of Porto Santo and also from ail 

 the endemics of the Azores. 



When we catalogue the Porto Santo flora, deriving our data 

 from the excellent "Flora do Archipelago da Madeira" by C. A. 

 de Menezes (1914), it becomes very evident that a large pro- 

 portion of the species now existing there consists of introduced 

 weeds, or cultivated plants run wild. One gets the impression 

 that all the "tramp" plants of southern Europe are there. 

 Going through the list I find about 160 species (out of a total of 

 316) which may I lliink certainly be referred to this category, 

 and perhajjs 20 or 30 others might be included. But this 



