5i8 Journal of Agricultural Research voi. xii.no. lo 



Although typically there are two rather distinct types with regard to 

 stamen development in both cultivated and wild clones of the straw- 

 berry — namely, the perfect stamens bearing normal pollen and the 

 staminodia of the pistillate varieties — there are apparently a series con- 

 necting these two conditions. 



Figures ii, 12, 13, 14, 15, and 16 of text figure 3 show the range of de- 

 velopment in size of the staminodia on some pistillate plants, and i, 2, j, 

 5, and 6 show the relative size of normal anthers. In actual size the two 

 types closely approach one another. With regard to development of re- 

 productive tissue, there is considerable difference. The normal stamens 

 naturally carry pollen development through to completion. The stami- 

 nodia, on the other hand, never produce normal pollen, but show some 

 variations in the extent to which development is carried. Figures A, 

 B, C, and D, Plate 36, are photographs of cross sections of staminodia, 

 figures A and B being cross sections of two loculi of staminodia of Crescent 

 and Columbia, respectively, in both of which varieties the staminodia are 

 rather prominent. Plate 36, C, is from the seedling Minnesota 1017 X 

 Progressive, 1 1-59, which produces very large and prominent staminodia. 

 Here there are distinct evidences of early degeneration of the repro- 

 ductive tissue, probably pollen mother cells, although the early stages of 

 this variety have not been studied. Figure D (PI. 36) is from a stami- 

 nodium of a pistillate variety which produces extremely small stami- 

 nodia. There is no evidence of any reproductive tissue whatever having 



been produced. 



Janczewski {24) has studied the stamen condition in some of the 



diecious species of Ribes and finds that in the pistillate flowers small sta- 

 mens develop. Their internal development soon ceases and abortion of the 

 reproductive tissue takes place. He considers that the small dark stain- 

 ing mass which he found in the staminodia was made up of the decom- 

 posed pollen mother cells. Often the cavity left by the breaking down 

 of the pollen mother cells was filled with parenchyma which had grown 

 in from the wails. Gates (17) found the same condition in some anthers 

 of Oenothera lata. Apparently the parenchymatous tissue filling the 

 staminodia of Crescent and Columbia is not of this origin, as early stages 

 show no signs of the formation of pollen mother cells. 



Intermediate anthers. — In studying the anther types of F. virginiana 

 certain clones were found which on first examination appeared to be 

 producing normal stamens, but on closer examination were found to 

 contain either a dark staining disintegrated mass or completely aborted 

 microspores, the walls of which, in some cases, were disintegrating. 

 These are apparently intermediate types between the staminodia and 

 normal anthers. Similar types of anthers are" not infrequently found 

 in the primary flowers of many wild staminate clones. 



A study of the intermediate stamens of F. -virginiana indicates that 

 pollen development is generally carried to the homceotypic division 



