

330 BOTANICAL GAZETTE [april 



Overholts 18 has monographed the Polyporaceae of the central states, j 



including the states extending from Ohio to North Dakota and southward to ( 



Kentucky and Kansas. He recognizes 132 species in 7 genera, the species of 

 Poria and Merulius being omitted because " practically nothing is known of 

 them at present." The large genus is Poly par us, with 88 species; following it 

 are Fames with 23 species and Trametes with 10 species. The keys and con- 

 trasted descriptions should make the identification of species comparatively 

 easy. Perhaps the author is to be congratulated that he did not see fit to 

 propose any new species. 



Smith 19 has described 10 new species and 5 new varieties of algae from the 

 lakes of Wisconsin, and also a new genus (Gloeocystopsis) , which combines the 

 external morphological characters of Gleocystis and Nephrocytium. 



Stevens, 20 in a synoptical account of the species of Meliola occurring 

 in Porto Rico, recognizes 95 species, and describes 62 of them as new. — 

 J. M. C. 



Sulphur nutrition. — Although sulphates have little effect on the soil flora, 

 and cannot function therefore as important fertilizers for all crops, the fact 

 that the sulphur content of most soils is rather Iqw, and that certain classes 

 of plants use considerable quantities of sulphur in metabolism, leads to the 

 possibility of sulphur deficiency becoming in certain cases a limiting factor to 

 crop production. Hart and Tottingham 21 have made some greenhouse \ 



studies on the relation of elemental sulphur and various sulphates to the nutri- 

 tion of certain of the Leguminosae, Cruciferae, and Gramineae, groups differ- 

 ing somewhat in their need of sulphur. They find that sulphates may be 

 beneficial to certain crops, even when functioning only as a source of sulphur. 



Calcium sulphate in general gave better results than sodium sulphate. It 

 increased the dry weight produced by red clover 23 per cent. With rape the 

 greatest beneficial influence was noted when the calcium sulphate was used in 

 addition to a complete fertilizer. The increase due to the sulphate in this 1 



case was 17 per cent. In both plants the roots were much elongated by the 

 sulphate, so that a much larger volume of soil is laid under contribution to the 

 plant, and its ability to withstand drought is much increased. The sulphate 

 therefore not only meets the special needs of these plants for sulphur but 

 improves the general physiological conditions. 



ERHOLTS 



Wash. Univ. Studies 3:3-98. pis. 8. 1915. 



19 Smith, Gilbert Morgan, New and interesting algae from the lakes of Wis- 

 consin. Bull. Torr. Bot. Club 43:471-483. 1916. 



20 



Steven 



111. Biol. Mono- 



graphs 2 : 1-86. pis. 5. 1916. 



21 



Hart, E. B., and Tottingham, W. E., Relation of sulphur compounds to plant 



! 



nutrition. Jour. Agric. Research 5 : 233-249. 1915. 



