CHAP. IV. 



VIOLA TRICOLOR. 



123 



the open ground ; and the eight tallest plants in each row were 

 measured, with the following result : 



TABLE XL. 



Reseda odorata (seedlings from a semi-seJf-sterile Plant, planted 

 in the open ground). 



The average height of the eight crossed plants is here 26 '92, 

 and that of the eight self-fertilised plants 23 '54 inches; or as 

 100 to 90. 



IX. VIOLACE^}. VIOLA TBICOLOB. 



Whilst the flowers of the common cultivated heartsease are 

 young, the anthers shed their pollen into a little semi-cylin- 

 drical passage, formed by the basal portion of the lower petal, 

 and surrounded by papillae. The pollen thus collected lies 

 close beneath the stigma, but can seldom gain access into its 

 cavity, except by the aid of insects, which pass their proboscides 

 down this passage into the nectary.* Consequently when I 

 covered up a large plant of a cultivated variety, it set only 

 eighteen capsules, and most of these contained very few good 

 seeds several from only one to three; whereas an equally fine 



* The flowers of this plant 

 have been fully described by 

 Sprengel, Hildebrand, Delpino, 

 and H. Muller. The latter author 

 sums up all the previous obser- 

 vations in hia l Befruchtung der 

 Blumen,' and in ' Nature,' Nov. 

 20, 1873, p. 44. See also Mr. A. W. 



Bennett, in 'Nature,' May 15, 

 1873, p. 50; and some remarks 

 by Mr. Kitchener, ibid. p. 143. 

 The facts which follow on the 

 effects of covering up a plant 

 of V. tricolor have been quoted 

 by Sir J. Lubbock in hig ' British 

 Wild Flowers,' &c. p. 62. 



