AGRICULTURAL BOTANY. 827 



1181, 1782). — In 1904 the author made an examination of the root system of a 

 horse chestnut tree growing in the garden of the School of Forestry at Zurich, 

 and found the kiteral rootlets full of hyphse and transformed into typical endo- 

 trophic mycorrhiza. Roots of this and of Pavia were obtained from several 

 places, and some showed infestation while others were entirely immune. 



To determine the cause of the unequal distribution, horse chestnuts were set 

 out in 1907, some of the younger trees being cultivated in garden beds, others 

 placed in pots in sterilized soil and grown near wild trees, and an examination 

 made of the roots in 1911. Only those which were grown in pots without 

 direct communication with the soil were infested. Those grown in the open 

 beds or in pots the bottoms of which were open contained no trace of hyphse. 

 The trees grown in the confined soil area that showed the presence of mycor- 

 I'hiza were small, though healthy and normal. It is believed that the develop- 

 ment of the trees was retarded by the small amount of soil present, thus ex- 

 plaining the foi'matiou of mycorrhiza. 



The results of the author's investigations led him to the conclusion that the 

 penetration and development of hyphse in the root system of ^T^^sculus and 

 Pavia, especially in the short roots, is a phenomenon of parasitism and not of 

 symbiosis. The parasitism, however, is considered almost harmless. 



The specific nature of the organism has not been determined. It was found 

 that the activity of the fungus ceased with the drying of the rootlets. 



Inhibiting' factors in Lychnis and Papaver, G. H. Shull (Ahft. in Science, 

 11. ser., 35 {1912), No. S91, p. 159). — A cross between white-flowered and purple- 

 flowered forms of L. dioica from Germany is described, which in the Fi genera- 

 tion is predominantly white-flowered, though previous crosses have given onlsj- 

 purple-flowered offspring. The white-flowered form from Germany, in crosses 

 with a recessive white American strain, produced, in one case a white-flowered 

 and in the other a purple-flowered form in the Fi generation. In P. rhceas 

 white has usually proved, recessive to color, but in a cross between red and 

 white, white progeny in the Fi were produced. 



The experiments suggest the existence of 2 complementary inhibiting factors, 

 which have no effect except when coexisting in the same plant. 



Inheritance in Capsella, H. .Hus {Ahs. in Science, n. ser., 35 (1912), No. 

 891, p. 159). — The author states that seedlings from a single plant of C. tursa 

 pastoris can be classed into 3 groups, broad leaved, narrow leaved, and linear 

 leaved. These forms occur approximately in the proportion 2:2:1. This pro- 

 portion has been maintained for 3 generations, and is considered as a simple 

 Mendelian splitting in the F2 generation of the Zea type, complicated by a 

 defective inheritance ratio. 



The relationship of the wheats, A. Schulz {ZtscJir. Gcsam. Getrcidew., 3 

 (1911), No. 10, pp. 209-211). — This is a brief discussion of the supposed re- 

 lationships as to descent existing among the several species of Triticum. The 

 8 forms considered are here placed in 2 main divisions, viz (1), the group of 

 bearded wheats, including T. monococcum, T. spelta, and T. dicoccum, and (2) 

 the group of naked or beardless wheats, comprising T. vulgarc, T. compactum, 

 T. turgidum, T. durum, and T. polonicum. The 2 main groups are further dis- 

 tinguished by the manner of breaking of the ripe ear spindle, the time of 

 ripening, etc. Their possible relations as group forms to cultivated forms are 

 also touched upon. 



The anatomical structure of the wood of the graft hybrid Cytisus adami 

 and its components, H. H. Janssonius and J. W. Moll (Rcc. Trav. Bot. 

 N6erland., 8 (1911), No. 3-4, PP. 333-368, figs. 6).— A report is given of an 

 anatomical study of the wood of C. adami, which is claimed to be a graft 



