NOTES AND ABSTRACTS. 



389 



The uredo appears late in spring, and rusted grasses do not 

 produce the uredo again after being housed during the winter. The 

 wintering of P. graminis as mycehum in the tissues is considered very 

 doubtful. 



The pericarp of rusted wheat grains is frequently filled with rust 

 mycehum and numerous pustules of teleutospores. Pieces of mycelium 

 resembling rust were found in the cells of the scutellum close to the 

 growing plant. Teleutospores in some of the germinating grains 

 appeared to be germinating in a palmella stage. 



There are many other points of great practical importance in this 

 paper.— (7. F. S. E. 



RhodOChytrium. By Eobert F. Griggs {Bot. Gaz. pp. 127-173, 

 Feb. 1912 ; 6 plates). — The author gives a very full description of the 

 cytology and life-history of this parasite. 



It seems to be transitional between protoccoid algae and certain 

 fungi. He finds a close relationship to the algae through Phyllo- 

 hium, and in cell division, &c., it resembles Synchyirium. No mor- 

 phological difference was found between the three races of this plant, 

 though they are geographically isolated and attached to different 

 hosts.— G. F. S. E. 



Rhododendron Augfustinii and R. Farg-esii. By C. P. Eaffill 



(Gard. Chron. p. 4 ; July 6, 1912). — Figures and descriptions of these 

 two newly introduced Chinese species. — E. A. B. 



Romneya Coulteri. I. By P. Lecolier. II. By J. Gerome (Le 

 Ja-rd. XXV. 592, p. 305, Oct. 20, 1911; 4 figs.). — A general article on 

 the Romneya, pointing out that it thrives well in dry seasons and needs 

 little watering. It is also more hardy than is commonly supposed, 

 and requires only slight if any protection in the winter. Its utility as 

 a cut flower is also emphasized, as it lasts well in water. — E. A. W, 



Rootcap, Types of. By Giinther H. Krole, Berlin {Beih. Bot. 

 Cmt. Bd. 28, Abt. i. Heft 1, pp. 134-158).— The author describes 

 and analyses the various methods of rootcap-formation given by 

 previous authors, and gives a systematically arranged list of 571 

 species in which the initial layers and their origin have been observed. 



A single (or several in Marattiaceae) three-sided initial cell charac- 

 terizes most Ferns and Marsilia. Three-sided initi,al cell (with plerome, 

 periblem, epidermis) is found in Equisetum, one initial cell (with 

 plerome, periblem, dermatogen, and calyptrogen) which is four-sided 

 in Lycopodium and two-sided in Isoetes. Selaginella also has one or 

 several two-sided initial cells. 



The Gymnosperms have plerome and periblem, which last forms 

 the rootcap and epidermis. 



Dicotyledons. — Most possess plerome, periblem, and dermatogen; 

 the latter forms the rootcap. Others, however, have plerome and 

 common initials for the other tissues. Others, again {Myrica, Eanun- 



