74 Species Hijhrids of Digitalis 



characters each of these characters was developed rather differently 

 according to which species was used as female parent, or whether the 

 one hybrid possessed characters derived from its female parent which 

 were entirely absent from the reciprocal and vice versa. 



The D. grandiflora used in these experiments was raised from seed 

 obtained from Haage and Schmidt of Germany and has given offspring 

 true to type for several generations. 



The D. purpurea bore flowers of a deep purple colour. Unfortunately 

 the same plant was not used for both crosses : that u.sed in the case of 

 (D.P.xD.G.) subsequent breeding proved to be a pure strain. There 

 is no reason to believe that the plant used in the reciprocal cross was 

 otherwise, although this was not proved by selfing. Below is a detailed 

 comparison of these four plants — two parents and reciprocals. 



1. Stature. D.P. = 4 feet or more. AG. = about 2 feet. (D.P. 

 X D.G.) = about 3 feet. {D.G. x D.P.) = about 2^ feet. 



Thus the stature of the hybrids is intermediate between the parents ; 

 that having the taller female parent being of greater size than the 

 reciprocal. 



Of course these numbers are only to be taken in quite a general 

 sense, as a well-grown plant of {D.G. x D.P.) would no doubt be taller 

 than a poorly grown plant of {D.P. x D.G). Still, under similar cultural 

 conditions there seems no doubt that {D.P. x D.G.) is distinctly taller 

 than {D.G. x D.P.). The season was a very dry one, so that all the 

 plants were rather below the normal height. 



2. Inflorescence. The form of the inflorescence in the two species is 

 quite distinct; the raceme of D.P. is straight (Plate III, tig. 1), while 

 that of D.G. is strongly curved at the apex (Plate III, fig. 2). In 

 {D.P. X D.G.) the end of the raceme is curved, but not through more 

 than a right angle — the plants having in consequence quite a character- 

 istic appearance (Plate III, fig. 3). In {D.G. x D.P.) the form of the 

 inflorescence is indistinguishable from that of D.G. 



3 and 4. Flower. The corolla of D.P. is dark magenta-purple and 

 the lower side of the tube marked on the inside with dark purple spots 

 of varying size (Plate IV, fig. 4). That of D.G. is a i-ather dark yellow 

 (the shade varying somewhat in different jjlants) and in place of the 

 spots occurring in D.P. is a brown network-like pattern (Plate IV, 

 fig. 5). This network marks the position of the veins of the corolla and, 

 as can be seen from the figure, the markings are thicker and more 

 pronounced transversely. Comparing now the hybrids : {D.P. x D.G.) 

 is a salmon-purple colour with dark red spots (Plate IV, fig. 6), while 



