90 



by the authors of the paper here reviewed are among the most 

 interesting and valuable of any recorded. The present article 

 concisely presents the facts gained and hypotheses suggested by 

 recent observations. While the assimilation of free nitrogen by 

 chlorophyllous plants may be disposed of as not proven, it is 

 assumed by some that it is brought into combination in various 

 ways within the soil under the action of electricity, fungi or 

 micro-organisms, and among the latter the mycorhiza hyphae of 

 Cupuliferae, made known by Frank, and the nodules on the roots 

 of certain Leguminosae have been suspected as agents of nitrifi- 

 cation. Drs. Lawes and Gilbert are not inclined to attribute any 

 considerable action to the structures mentioned, but, pointing out 

 that while even the feebly nitrogenous sub-soil of Rothamsted 

 (containing only 0.04% of nitrogen) carries some 20,000 pounds 

 of the element per acre, suggest that the Fungi, etc., may serve 

 the crops by in some way bringing this large store of combined 

 nitrogen into a soluble condition for assimilation. — N. L. B. 



Index to Recent American Botanical Literature. 



Agricultural College of Michigan — Annual Report, 1887. — L. H. 

 Bailey, Jr, (Bulletin No. 31, pamphlet, 96 pp.; illustrated.) 

 This contains a good deal of interesting and valuable infor- 

 mation on practical horticulture. 



Bacteria from a Botanical Standpoint. — Wm. Trelease. (Weekly 

 Medical Review, xvii., pp. 88-92 and 127 131.) 

 A brief and clear account of these organisms as studied in the 

 botanical rather than the pathological laboratory, though the 

 paper concludes with some pretty strong advice to the physicians 

 of St. Louis regarding the water-supply of the city. 

 Botanical Institute at Tiibingen.—DoxxgXdiS H. Campbell. (Bot 



Gaz., xiii., pp 



W 



Characece of America— Part /.—Dr. T. F. Allen. (Pamph.. 

 large 8vo., pp. 64, 55 illustrations; New York, 1888; pub- 

 lished by the author.) 



The very welcome and long expected results of Dr. Allen's 

 prolonged studies of this neglected class of plants come to us in 

 the form of a beautifully printed and illustrated work which must 

 stimulate their investigation, and for the first time affords a ready 



