NOTES ON RECENT RESEARCH. 



709 



belonging to twenty-four genera of the tribes llliamnca, Colletice, and 

 Gouanue. There is a short account of the special characters of each 

 species. The leaves show great variation in size and general character. 

 In most of them there is no clear differentiation of the mesophyll into 

 palisade and spongy parenchyma. The entire mesophyll consists of 

 several layers of cells elongated like palisade cells. Very often the 

 inner walls of the epidermis cells become mucilaginous. There are 

 characteristic mucilage-containing cells in the collenchyma below the 

 bundles. The leaf is generally bifacial. Some species of CeanotJius 

 show deep grooves between the nerves on the under side, in which lie the 

 stomata, protected by hairs. These sunken parts of the leaf have only 

 one layer of palisade-like cells, while the rest may have seven to eight 

 layers. The crystals show great variety as regards both character and 

 position. Small stellate crystal cells are common in the spongy and bast 

 parenchyma. Long crystals found in special thin-walled cells characterise 

 the Gouania. These " styloids " often reach from upper to lower epi- 

 dermis, and produce the transparent points in the leaf. Short clino- 

 rhombic crystals also occur, as well as small hendyoedic and aggregates 

 of crystals. The hairs vary from long unicellular trichomes to stellate and 

 stalked forms. — G. F. S.-E. 



Rusts. 



Rust Fungi, Experiments with. By H. Klebahn (Zeit.f. Pflanzn 

 xii. 1902 ; pp. 17-44, and 132-151 ; 5 figs.). — The tenth annual report of 

 the author on his experiments with the cultivation of hetercecious 

 Uredincce with incomplete life-histories. While generally notes on progress 

 of his work, each year brings some problem solved. Parts I. to VI. deal 

 with the Mclampsorcce of Willows and Poplars. An excellent summary 

 of results on the species occurring on Willows is given by Plowright 

 (Gard. CJiron. July 1902, p. 5">). In regard to Poplars the investigations 

 confirm that M. populina includes two forms : (1) M. allii-populina, 

 caeoma on Allium ascalonicum, uredo on Populus nigra, cana- 

 densis, and balsamifcra ; (2) M. laricis-populina, caeoma on Larch, 

 uredo on various Poplars. Other Poplar Melampsorcaz are noticed. 

 Part VII. Experiments with needle-rusts of Pines : (1) Coleosporinm 

 Pulsatilla, Lev., aecidia on Scots Pine, uredo on Pulsatilla pratensis 

 and P. vulgaris. (2) Col. Inulce, Fischer, connection with rocidia 

 on Scots Pine confirmed. VIII. Rind-rust of Pines : (1) Identity of 

 the three species Cronartium asclepiadcum, flaccidum, and Nemesice 

 confirmed. (2) Periderm him pini, negative results with species of 

 Galium, kc. IX. JEcidium clatinum; confirms Fischer's results (see R.H.S. 

 Journal, vol. xxvii. p. 272). X. Chrysomyxa Ledi. Successful infection 

 of Ledum palustre with aecidia from Coniferce. XI. AZcidium Pastinacce 

 Rostr. ; confirms connection with a Vrcmyces on Scirpus. XH. A 

 Puccinia on Bistort gave aecidia on Angelica syhestris and Carum Carvi, 

 the name P. Angelicce-bistortce, Kleb., is suggested ; this confirms and 

 extends Soppitt's experiments. XIII. Rusts on Ribes and Carex spp. ; 

 reports new experiments. XIV. An aecidium on Ranunculus acris, L., 

 infected Meadow Foxtail (Alcpccuius), htnee lelongs to Puccinia 

 pcrplexans, Plowr. XV. Confirms connection of JEcidium gravcolens, 



