PLANT HYBRIDIZATION BEFORE MENDEL 



273 



produced, not in blended fashion, but as distinct structures reduced 

 either in size or number or both." (p. 98.) 



Following are the details of measurements in the parents and 

 the first generation hybrid, for the principal characters studied. 



Tissue 

 Leaves 



Presence of 

 stomata 



D. filiformis D. intermedia 



8 in. long; 1/2 Av. 1 1/2 in. 

 in. wide. Petiole, long. Blade 1/5 



3/8 in.-5 in. 

 long, non-gland- 

 ular 



in. wide, sharp 

 difference be- 

 tween petiole 

 and lamina. 

 Base of the peti- 

 ole has a quad- 

 rangular area 

 also 



Upper epidermal Upper epidermal 

 cells of this cells of this 



area average area, 225x28/", 



250x38/^. Chlo- and contain a 

 roplasts few, very few small 



scattered and chloroplasts 



small ; each 2.5 

 to 3/" diam. 

 Stomata not 

 present on this 

 area 



Lower epidermis Lower epidermis 

 of this area has has elongated 



Hybrid 



Typical summer 

 leaves may be 

 10-11 in. and 

 greatly attenu- 

 ated at tips, but 

 average 3 1/2 

 in., of which 1/2 

 in. may be peti- 

 ole. No basal 

 quadrangular 

 area; intermedi- 

 ate in size and 

 shape 



Upper epidermal 

 cells, 188- 

 200x32/". Chloro- 

 plasts small and 

 few 



cells longer and 

 narrower, 

 185x20/", well 

 filled with large 

 chloroplasts, 

 each 7.5-8/" 

 across 



narrow cells, 

 200-225x15/" 



Lower epidermal 

 cells average 

 186-195x21/" 

 and chloroplasts 

 measure 2.5/" 



A few stomata, 

 each 40x23-25/". 

 2-celled sessile 

 glands of stoma- 

 like character 



No stomata, and 

 instead of the 

 2-celled glands, 

 there are gland- 

 ular bifid hairs 



Numerous 

 2-celled glands, 

 and also bifid 

 hairs, but of re- 

 duced size 



2-celled gland- 

 ular hairs 



28x18/", slightly 

 elevated above 

 surface 



45-50At high X 37/^ 

 across 



33/i high X 32/t 

 across 



