538 



SCIENCE. 



[N. S. Vol. VII. No. 172. 



Botanical Observations on the Azores. By Wil- 

 liam Teelbase. 8tli Annual Report, Mis- 

 souri Botanical Garden, 1897. 

 The title of this work, and the appearance of 

 its pages — crowded with names and biblio- 

 graphical references — do not suggest anything 

 of general interest. Nevertheless there is per- 

 haps more to attract the general naturalist than 

 the specialist in botany, on closer examination ; 

 for while the new species and varieties are few 

 and mostly of minor interest, the list of the 

 flora — complete to date — forms a valuable con- 

 tribution to our knowledge of plant distribution. 

 Dr. A. K. Wallace, in Island Life (2d Ed., 

 1892), has given us an excellent summary of 

 ■what is known about the natural history of the 

 Azores, showing that they are truly oceanic 

 islands, but that the number of endemic 

 forms is comparatively small. There is one 

 peculiar bird — a bullfinch ; there are fourteen 

 peculiar beetles, including two peculiar genera 

 of weevils ; of the sixty-nine land shells, as 

 many as thirty-two are said to be peculiar ; of 

 the flowering plants, Dr. Wallace, following 

 Mr. H. O. Watson, cites 40 as endemic ; Dr. 

 Trelease reduces these to 36, and not all of 

 this smaller number are as distinct as might be 

 wished. The genera containing the endemic 

 plants are as follows : 



Phanerogams : Cardamine, Cerastium, Hyperi- 

 cum, ViciaRubus, Sanicula, Ammi (S), Chiero- 

 phyllum, Scabiosa, Bellin, Tolpis, Picris (S), 

 Laciiica, Campanula, Vaccinixim, Erica, Lysima- 

 chia, Myosotis {S), Veronica, Euphrasia, Per sea. 

 Euphorbia (S), Habenaria {Z), Luzula, Carex 

 {3), Solcus, Deschampsia, Festuca, Juniperus. 

 Pteeidophytes : a Selaginella and an Isoetes ; 



no endemic ferns. 

 Musci : Sciaromium, Astrodontium, Bryum, 

 Breutelia, Glyphomitrium, Hypophila, Campy- 

 lopus {2), Sphagnum (S). 

 A'LGM, : Bryopsis. Lichenes : Lecidia. 



Dr. Trelease remarks : ' ' More evidently 

 than is the case with the Canary Islands, the 

 endemic flora of the Azores appears to be un- 

 dergoing a gradual reduction, jjartly because of 

 the utilization of all available land for agricul- 

 tural purposes. In some of the islands even 

 the high-lying pasture lands are being restocked 

 with foreign plants from the European and 



American continents, in the belief that they are 

 more valuable than those native to the islands ; 

 but, as a rule, such changes as are taking place 

 above the zone of cultivation are fought out on 

 the lines of the survival of the fittest." Again 

 he remarks: "It is observable that a large 

 percentage of the species referred to on Mr. 

 Watson's authority only have not been de- 

 tected since the days-of his own collecting and 

 that of Mr. Hunt, a half century ago." 



This rapid change, due to the direct and in- 

 direct influence of man, has doubtless already 

 obliterated much of the native fauna and flora. 

 But, as Wallace shows, the islands must in past 

 times have been exposed in a lesser degree to 

 invasions of foreign organisms, and each species 

 which established itself must have disturbed 

 the existing balance. It is said that scarcely a 

 storm occurs in spring or autumn without bring- 

 ing one or more species of birds foreign to the 

 islands, and it is not necessary to point out how 

 these numerous stragglers must have brought 

 seeds from time to time. 



Nevertheless the islands contain some rem- 

 nants of an ancient fauna and flora, and the 

 proportion of endemic forms, as seen from the 

 above data, differs in the different groups. Fol- 

 lowing the train of thought suggested by Wal- 

 lace, we may probably establish the following 

 law : The percentage of endemic forms in any 

 group in the Azores is approximately in inverse 

 ratio to the facilities that group has for reaching 

 the islands from elsewhere. In other words, those 

 groups which show very ancient members are 

 precisely those which have least been disturbed 

 by competitors from without. 



It is, from this point of view, easy to under- 

 stand why the land mollusca show so many 

 endemic types, including a slug {Plutonia allan- 

 tica) belonging not only to a peculiar genus, but 

 a peculiar subfamily. On the other hand, we 

 see why there is only one endemic bird, and 

 that not very distinct. Applying the same rule 

 to the flowering plants, it seems that the en- 

 demic species belong on the whole to genera 

 which would not be very easily introduced by 

 birds or by the wind. This, however, is a mat- 

 ter which needs to be critically examined by a 

 botanist, and it would be especially interesting 

 to know how well the seeds of the genera con- 



