330 Floristik, Geographie, Systematik etc. 



The author gave special attention to torms of critical species, 

 since a study of the geographica! distribution of „elementary" spe- 

 cies or forms maj^ contribute to the interpretation of the immigra- 

 tion of the postglacial flora and the paths this may have foUowtd. 

 The remarks are critical and include recognition of new forms as 

 well as notes on distribution in Britain. Amongst those discussed 

 at greater length are: NympJiaea alba var. occidentaiis Ostf. 

 nov. var., which is distinguished from N. alba and A^ Candida 

 Presl.; a Sagina observed on Ben La wer s is regarded as a hybrid 

 (S. procunibens L. X saginoides (L.) Dalla Torre); Alchimilla acuti- 

 denSj Buser, Lindb, fil. ampl.; Erica Mackayi Hook. X tetralix L., 

 a species much discussed, is regarded as a hybrid = E. Praegeri 

 nov. hybr.; Euphrasia spp.; Junciis, bitfonius L. var. ranarins (Song, 

 et Perrier; Scirpiis caespitosus L. vars., etc. 



VII. Graebnep, P., Pflanzengeographische Eindrücke 

 auf den Britischen Inseln. (XI. p. 170—176.) 



The Chief impression conveyed to a phytogeographer from 

 Central Europe is that in a land so long subjected to farming 

 as Britain, especially through the widespread sheep-grazing, the 

 natural Vegetation is so altered as to render it hard to picture 

 what plant-formations existed before man put the land under culti- 

 vation. Of Crossfell the author says: „never in Central Europe 

 have 1 Seen Vegetation formations so poor in species as on several 

 areas on the slopes and summit of such a hill." The list given 

 bears this out, and it is regarded that not altogether sheep-grazing 

 js to blame, but also the climate. Ben Lawers is put on a diffe- 

 rent plane, and one cause given for the much greater variety of 

 species is that sheep have more difficulty, owing to altitude and 

 topograph3^ in damaging the Vegetation. The lower slopes of the 

 hills are regarded as having been formerlj^ forest, as confirmed by 

 the presence of Pteris aquilina and Liisida sylvatica. The existing 

 woods are greatly altered bj^ inroads from grazing animals and the 

 introduction of such trees as Acer psendoplatanus which might be 

 regarded as native by any one unfamiliar with the history of the 

 Vegetation. Undisturbed „Hochmoor" was never seen; everywbere 

 there was alteration by drainage, and even deep moss-moors sho- 

 wed the same physiognomy as secondary moors in the North 

 German piain. A connected covering of Sphagmnn was not seen. 

 One area of the Pennines with Evioplioriim moor, when compared 

 with moors at similar altitudes in Central Europe (e. g. „Brocken- 

 feldern"), showed a total absence of the shrubb}^ Vegetation, and 

 this is regarded as a sign of recent change. Amongst other causes 

 in this retrogressive change „Moorbruch" or moss-flow is suggested 

 as an important agent. Ireland furnishes several impressions: oc- 

 currence of Calliaia on limestone (as in Germany); the abundance 

 of such American species as Eriocaulon septangidare\ the influence 

 of the moist western climate on the development of epiphytism in 

 ferns, and on the Vegetation of woods with Arbiitus Unedo. The 

 occurrence of many introduced plants growing freely wild and as 

 if at home is also commented on and examples given. 



VIII. Clements, F. E., Some Impressions and Reflec- 



tions. (XI. p. 177 — 179.) 



Amongst other features, special attention is directed to the 

 following. The Norfolk Broads prcsent a fascinating succession and 

 are a region extremely favourable to the studj- of habitat equiva- 



