NOTES AND ABSTRACTS. 



NOTES AND ABSTEACTS. 



Aliens in Middle Europe. By Prof. F. Hock {Beih. Bot. Cen. 

 XXVI. 2 Abt. Heft iii. pp. 391-433; 19lO).— A further list of 358 plants 

 which have estabhshed themselves in Europe during the last five years, 

 or which have not hitherto been recorded by the author. 



During the last sixty yearfe abbut 1000 species have been re- 

 corded, which is at the rate of fifteen new species per annum. By 

 far the greater number are Composites, grasses, Leguminosae, and 

 Cruciferae'. 



Most of these strangers belong to the Mediterranean or Spain, 

 but there are some from Australia, the Himalayas, Japan, and ftom 

 both South and North America. Most have been accidentally intro- 

 duced and are not garden escapes. — G. F. S.-E. 



Aloineae, Anatomy of. By Dr. F. Lange {Boi. Zeit. Abt. i. 

 I-Ieft i. arid ii. pp. 1-47; with 33 hgs. ; Feb. 18, 1910).— These 

 anatomical researches upon the systematic classification of the 

 Aloineae {Aloe, Gasteriay Haworthia, Apicra, and Lomantophylluiri) 

 contain a full description of the microscopic anatomy of the leaf for 

 each of the genera. This is given first in general and then in detail 

 for 56 species of AloCy 26 of Gasteria, 17 Haworthia, 4 Apicra, and 

 1 Lonianiopliyiluju. 



An expert botanist who is familiar with microscopic technique 

 should be able to determine any of the species studied by the author 

 from the microscopic anatomy of the leaf alone. Some of .the dis- 

 tinguishing points are perhaps difficult in practice." A difference in 

 ihe radial diameter of a vascular bundle of 25 micromillimetres — e.g. 

 between 375 and 400 — is not very easy to distinguish. Measure- 

 luents of the thickness of the cuticle, as contrasted with that of the 

 thiclened layers of the epidermis, also seem difficult to use for 

 diaguostic purposes, and such measurements are relied upon for the 

 |)rimary groups of Aloe. 



The author discusses the question as to how far the ordinary 

 systematic classification of the Aloineae is confirmed by anatomical 

 structure, and gives a scheme showing their affinities as determined by 

 the microscopic anatomy of the leaf.. — G. F. S.-E. 



Anemone Rusts. By E.. W. D. Holway {Gard. Chron. xivii. (1910), 

 p. 67; Jan. 29). — A summ.ary of our knowledge concerning the rust 

 fungi attacking anemones and their alternative hosts is given, it being: 

 shown that one species has its alternative form on the plum and another 

 onPyrus Aucuparia. — F. J. C. 



