328 EXPERIMENT STATION RECORD. [Vol. 37 



with the distance from the escaping fumes, the temperature of the melting 

 tar, the age of the plant structures, and the species u.sed. 



Imperfection of pollen and mutability in the genus Rosa, Ruth D. Cole 

 (Bot. Gaz., 63 (1911), No. 2, pp. 110-123, pis. S).— A study of all obtainable 

 species of Rosa carried out by the author during the winter of 1915-16 is said 

 to have shown that these species are characterized by great variability and by 

 a large proportion of abortive pollen. From this it is inferred that these 

 species are largely of hybrid origin, due to contamination in nature, and hence 

 that the mutability of the species of this genus can not properly be used in 

 support of the mutation hypothesis. 



CEnothera lamarckiana velutina, H. »e Vkies {Bot. Gaz., 63 (1917), No. 1, 

 pp. 1-24, Pl- 1)- — Observations during several years of cultures from CEnothera 

 mutations having tended to show that such mutation phenomena are far more 

 complex than they were formerly assumed to be, the author is now giving 

 attention to the question whether the characters of CEnothera mutants and 

 hybrids are single or built up of a greater or less number of theoretically 

 independent units. (E. laniarcJciana velutina has been chosen for this work 

 on account of its alleged freedom from specific admixtures. A uuml>er of 

 cro.sses were made in 1915, but this article gives cliiefly a description of the 

 mutant itself and of those hybridizations which give proof of its right to the 

 name it bears. 



A study of this new mutant shows the existence of at least two recessive 

 characters in CE. lamarckwna, namely, the bubbles of the leaf blade and the 

 presence of typical empty seeds. 



The cowhage and related species, C. V. Piper (I'roc. Biol. Sac. Wash., SO 

 (1917), pp. 51-62). — In connection with investigations of the Florida velvet 

 bean and other cultivated forms of velvet bean, the author has made a study 

 of various related species characterized by having stinging hairs on the calyx 

 and pods. The .'species of Stizolobium which are distinguislied from Mucima 

 by well defined characteri.stics are grouped under two subgenera. The name 

 for the well-known stinging-haired species should be S. pruricns. S. pruritum 

 is described as a new combination with several varieties, and S. inicrospermnvx, 

 S. venulosum, and S. forbesii are de.scribed as new spi»cies. S. hirsuium is the 

 name given for the species formerly known as M. hirsuta. 



FIELD CROPS. 



Dry farming in eastern New Mexico, J. E. Mundelt. and H. G. Smitu (Neio 

 Mexico Sta. Bui. 104 (1917), pp. 61, figs. 15). — This is a popular discussion of 

 general crop conditions and methods of farming in the dry-land area of eastern 

 New Mexico for the purpo.se of furnishing information to present and pros- 

 pective settlers. The information is based upon extensive ob.servations of dry- 

 farming methods in eastern New Mexico and other dry-farming districts and 

 on results obtainini In experiments conducted by the Oflice of Dry Land Agri- 

 culture, of the U. S. Department of Agriculture, at the dry-land field station, 

 Tucumcari, N. Mex. 



In addition to a discussion of the general factors to be considered in dry- 

 land agriculture, such as the limiting factors encounteretl, the cultural practices 

 employed, the most suitable crops, etc., considerable crop and climatological 

 data secured at the field station are presented and discussed. The average 

 annual precipitation at Tucumcari for a 12-year period was 16.21 in., over 70 

 per cent of which fell between April 1 and October 1. The average evaporation 

 from a free water surface for the 4-year period 1913 to 1916, inclusive, was 



