ISO BOTANICAL GAZETTE [august 



States isf(ivenwith great care and thoroughness. In the case of trees of 

 infrequent or rare occurrence the authority for each station is given. The 

 accuracy of these citations is made still more prominent by a list of author- 

 ites cited and of the trees with reference to which each is quoted. The 

 discussions of the habit of trees also show clearly the result of accurate and 

 painstaking field observations. The book is illustrated from excellent draw- 

 ings by Mrs. Elizabeth Gleason Bigelow. If this volume is to help the student 

 in the field, as the authors purpose, one would wish that the distinguishing 

 characters of the trees were more fully emphasized. The fact that the New 

 • England pines, for example, with one exception, may be readily distinguished 

 by the number of leaves in a sheath is not made prominent. A beginner 

 might read several pages before knowing this simple guide to the pines. A 

 combination of the fruit and leaf characters of the elms, birches, maples, 

 and poplars'often furnishes a ready test for the determination of the species. 

 That such facts are emphasized, perhaps with one exception, neither by keys 

 nor by typographic arrangement, will detract from the serviceableness of this 

 pocket-sized volume in actual field work. Throughout the volume the authors 

 use the terms fertile and sterile in referring to staminate and pistillate flowers. 

 Such terms perpetuate a mistaken conception, and they are too antiquated for 

 the present knowledge of plant reproduction. With these two exceptions 

 this volume has a stamp of thoroughness and accuracy not often found in 

 botanical handbooks designed for popular use. — C. D. Howe. 



A FLAX DISEASE of wide distribution and much economic importance 

 has been diagnosed, studied, and traced to its cause by Professor Henry L. 

 Bolley.''^ of the North Dakota Agricultural College ; and what is of practical 

 moment an efficient method has been found to check or possibly wholly pre- 

 vent the disease. Every cultivator knows that only a few successive crops of 

 flax can be grown on a given piece of land with profit. The yield constantly 

 decreases, and no system of manuring or cultivation has been found to over- 

 come the difficulty. An interval of seven to eleven years is required before 

 flax can be grown again with profit upon such a field. The trouble appears 

 to exist alike throughout Europe and America. Jt is now ascertained to be 

 due to a fungus, introduced chiefly with the seed, which is described as a new 

 species of Fusarium, as follows : 



FusARiUM LiNl Bolley in Bull. N. D. Agric. Station no. 50. p. 37- Vegetative 

 hyphoe light colored, 0.7-3 M in diameter, septate, branching irregularly, ramifying the 

 tissue of the stem and roots of the host. Spore beds (sporodochia) erumpent, com- 

 pact, slightly raised, distinct but closely grouped upon the stems, pale cream to flesh- 

 colored. Sporophores rather short and closely branched, or conidia sometmies 

 arising from wart-like or nearly sessile prominences upon a compact stromatic base. 



^^ Bolley, H. L., Flax wilt and flax-sick soil. Bull. N. D. Exper. Station, no. 5*^ ^ 

 PP- 27-57. 1901. 



