MISSISSIPPI EXPERIMENT STATION. 49 



dominant in one cross and the staminate in the other. In the Citrus 

 hybrids one parent plant was dominant in regard to certain characters, 

 as for instance, the size of epidermal cells of fruit, whether used as pistil- 

 late or staminate parent. C. aurantium was always dominant in respect 

 to this character. The influence of the staminate parent over the 

 epidermal structures of the hybrid, such as Gauchery (1902) pointed 

 out in a hybrid between Cistus salvifolius and Helianthemum halimi- 

 folium, does not show in the hybrids studied nor was there a uniform 

 influence of either parent as claimed by Denny (1872) for Pelargonium 

 hybrids. 



In the great majority of cases the cells of the hybrids studied were 

 intermediate between the corresponding cells of the parents. This 

 indicates that there must have been a complete blending of parental 

 elements. But exceptional cases showed that a blending had not taken 

 place, or if it had, it must have been followed by a segregation of char- 

 acters. For instance, certain epidermal cells of the calyx of the Cal- 

 ceolaria hybrid formed glandiilar hairs, and other epidermal cells 

 simple hairs, one parent having glandular hairs on its calyx and the 

 other simple only. 



A hybrid between Wild Goose Plum and Troth's Early. Peach 

 showed that segregation had advanced a step farther; whole patches of 

 epidermal cells of the twigs were exactly like the epidermal cells of either 

 parent. Hildebrand (1889) reports an interesting case of segregation 

 taking place within a single cell. In a hybrid between Oxalis latifolia 

 and O. tetraphylla he found the characteristic hairs of the two parent 

 species might both arise from a single epidermal cell of the hybrid. 



The fact that the starch grains of the Nicotiana Tabacum x N. 

 sylvestris hybrid were very much larger than the grains of either parent 

 indicates that there is more than a mere passing over of the leucoplastids 

 from the parents. The plastids from the two parents either fused, or 

 were subjected to some sort of a stimulus resulting from the mixing of 

 the parental elements which caused the production of the large grains. 

 AlacFarlane (1891) was of the opinion that many of the starch grains 

 of Hedychium hybrids were intermediate between those of their parents. 

 I am inclined to think that that is true of the grains of Nicotiana hybrids 

 too, especially as regards shape of grains, but the variation in shape in 

 the grains of the hybrid is so great that it is difficult to be certain. 



All of the species hybrids studied were sterile when self pollinated. 

 In all cases examined, the pollen began to break down while in the rest- 

 ing state. The ovules looked perfectly normal, but they were not 

 studied in detail. In the Nicotiana hybrids they failed to form seed 

 even when pollen from the parent species was used. In the Radish x 

 Kohlrabi hybrid, the ovules enlarged when the flowers were pollinated 

 with Kohlrabi pollen, but no perfect seed was formed. 



The Plum x Peach hybrid produced numerous flower buds but they 

 failed to open. From the tip of some, the stigmas and styles of several 

 rudimentary pistils projected. These pistils contained ovules in the 

 ovary of each. No stamens were developed. (For aii account of the 

 production and description of this hybrid see Report of Cornell Exp- 

 Station, for 1892.) 



