FIELD CROPS. 727 



injuries, tlio aw aiul kind of trees affected, and the results of microscopic 

 examinations and cliemical analyses of the injured trees are given. 



The grasses of Alaska, F. Lamson-Scribner and E. D. Merrill (U. S. Nat. 

 Mus., Contrih. Xat. Herbarium, 13, pt. 3, pp. J,l-92-\-lX, pis. 2).— This is a 

 systematic treatment, including a key to the tribes and genera, and description 

 of all of the species of grasses which have been properly credited to Alaska. 

 A bibliography of the literature on the grasses of Alaska is appended. 



An enumeration of Philippine Leguminosae, with keys to the genera and 

 species, E. D. Merrill (Philippine Jour. Sci., C. Bot., 5 (1910), No. 1, pp. i)-'t).-~ 

 This is a taxonomic discussion of 90 genera and 2S5 species of Legumiuosne, in 

 whirh 1 genus and 12 species are describetl as new. 



North American Trifoliums, Laura F. INIcDermott (San Francisco, 1910, 

 pp. 325, figs. 136). — This key to the genus Trifolium of North America includes 

 " all species native, or introduced and spontaneous, north of the Mexican 

 boundary." 



On the wild types of cultivated potatoes, P. Bebthault (Bui. Soc. Nat. 

 Agr. France, 70 (1910), No. 5, pp. 396-404, pis. 6).— This is a discussion of the 

 various types of wild potatoes, especially of Solatium commersonii and S. niaglia, 

 as the probable ancestors of the commonly cultivated Irish potato. 



On the interaction between scion and stock, A. Meyer and E. Schmidt 

 (Flora, 100 (1910), No. 3, pp. 317-,i97; abs. in Bot. Gaz., 50 (1910), No. 1, p. 

 73). — Following an extended discussion of similar investigations by other au- 

 thors, the I'esults are given of experiments on the formation, movements, and 

 storage of alkaloids, and of the mutual influence between scion and stock, in 

 heteroplastic grafts. 



Nicotiana tabacum was used as scion on N. afflnis and Solaniim tuberosum as 

 stocks, and Datura stramonium as scion on S. lyeopersicum and S. tuberosum. 

 It was found that a slow movement of the alkaloid took place from scion to 

 stock, apparently through the parenchyma rather than through the sieve tubes, 

 and that the stock of N. afflnis, which is normally poor in nicotine, accumulated 

 many times its normal amount of alkaolid, while the scion JV. tabacum, nor- 

 mally rich in nicotine, became relatively poor in it. 



With iS. tuberosum as stock for N. tabacum, the periderm cells of the former 

 become the main storage tissues of the nicotine, being most abundant in the 

 tissue of the stock just below the graft, and decreasing in amount as the cells 

 became more distant, until in the tuber none at all, or only a trace, appears. 



The underground organs of a few weeds, L. H. Pammel and Estelle D. 

 FoGEL (Proe. Iowa Acad. Sci., 16 (1909), pp. 31-40, pis. 2, figs. 16).— A morpho- 

 logical study is reported of the underground parts of some weeds, viz Canada 

 thistle (Cirsium arvense), horse nettle (Solanum carol inense), milkweed 

 (Asclepias syriaca), morning glory (Convolvulus sepium), bindweed (C arven- 

 sis), and quack grass (Agropyron repens), with especial reference to their use 

 as organs of propagation. 



Green hemiparasites, E. Heinriciier (Jahrb. Wiss. Bot. [Pringsheim], //7 

 (1910), No. 5, pp. 539-588, pis. 2, figs. 2). — In continuation of investigations on 

 the i)arasitic and hemiparasitic Khinauthacea; (E. S. R., 14, p. 841), the author 

 gives an account of investigations on respiration and assimilation in Alectorolo- 

 phus and Melampyrum. 



FIELD CROPS. 



[Experiments with alfalfa, corn, small grains, and potatoes], L. R. 

 WalukOxM and O. Grace (North Dakota Sta., lipt. Dickinson Substu., 1909, pp. 

 7-88; 59-64; 65, 66).— Among 68 strains of alfalfa tested, nearly two-thirds had 

 (he stand reduced over SO per cent by winterkilling, while 94 per cent winter- 



