434 EXPERIMENT STATION RECORD. [V*>1. ?.6 



The origin of new varieties of Nephrolepis by orthogenetic saltation. — 

 I, Progressive variations, R. C. Benedict (Bui. Torrey Bot. Cluh, 4S {1916). 

 No. 5, pp. 207-234, pis. 6). — This is a study of the varying progeny of the so- 

 called Boston fern, N. exaltata bostoniensis, known to have produced in about 

 15 years at least 60 horticultural forms which have been named. The great 

 majority at least have originated as bud sports. INIost of the descendants have 

 tended away from the original variety, some back toward it, but few, if any, 

 reaching the original form or the form of the immediate parent. 



The variations, which are produced and preserved in large numbers, partly 

 owing to the extensive production and care of the plant, are classified as pro- 

 gressive and regressive or reversive in regard to the parent form, the variation 

 coefficient of the former being very low as compared with that of the latter. 

 The variations are all discrete or discontinuous, the differences paralleling those 

 existing among many wild species of ferns and of flowering plants, except that 

 the horticultural forms do not possess adaptability to natural conditions, de- 

 creased vigor of growth usually characterizing departure from type. The ori- 

 gins or causes of variation have not been rendered apparent, but they appear 

 to proceed as if from internal stimulation under conditions apparently serving, 

 not as causes but as means of preserving the variants. 



The mutual influence of genotypical factors, Tine Tammes {Rec. Trav. Bot. 

 N^erland., IS {1916), No. 1, pp. 44-62). — Reporting the results of further in- 

 vestigations (E. S. R., 34, p. 629) on Linuni usitatissimum carried through sev- 

 eral generations, the author states that the plants not only possess factors ap- 

 parently independent of each other, but tliat in many cases the visible mani- 

 festation of a factor depends upon the presence or absence of several other 

 factors. Probably no factor is entirely independent of other factors. The rela- 

 tions of certain factors in case of flax varieties are discussed. 



Dry grassland of a high mountain park in northern Colorado, F. Ramaley 

 {Plant World, 19 {1916), No. 9, pp. 249-270, figs, fi).— Results of an ecological 

 study of a dry grassland park in northern Colorado at an elevation of about 

 9,000 ft. are given. The vegetation is described as low growing, consisting 

 largely of grasses and sedges, with many profusely flowering perennials. Five 

 seasonal periods are recognized, and a series of six societies is noted, corre- 

 sponding to historical stages from bare soil to the ultimate grassland of the 

 park. The effect of climate, soil, and evaporation and the importance of ro- 

 dents, etc., are briefly discussed. 



Fungus flora of Texas soils, F. C. Webkenthin {Phytopathology, 6 {1916), 

 No. 3, pp. 241-253, fig. 1). — A report is given of an investigation in which a 

 study was made of the fungi in three kinds of soil, one of which was from a 

 cotton field, another from a greenhouse, and the third from the university cam- 

 pus, where the soil had not been disturbed for at least 20 years. The frequency 

 and distribution of the fungi are indicated. 



The author states that to a depth of 4 in. the fungi were fairly uniformly 

 distributed, while below 4 in. no viable fungus spores were found. No marked 

 variation in species of fungi was observed that could be attributed to cultivated 

 or virgin soil. The climate is believed to have a great influence on the flora of 

 soils, species of Aspergillus being the dominant soil fungi of the South. Species 

 of Penicillium frequently found in northern soils are said to be rare in Texas 

 soils, and the Mucors are not so abundant in southern soils. Pathogenic fungi, 

 especially species of Fusarium, were found to live in the soil as saprophytes 

 throughout the winter. 



Relative importance of fungi and bacteria in soil, H. J. Conn {Science, 

 n. ser., 44 {1916), No. II46, pp. 857, 85S).— The author reports having tested 

 several soils by Waksman's method (E. S. R., 35. p. 820), using, however, only 



