316 CLEISTOGAMIC FLOWERS. CHAP. VIII. 



some cleistogamic flowers on the same plants; and the 

 result was that 14 capsules produced by the perfect 

 flowers contained on an average 9.85 seeds; and 17 

 capsules from the cleistogamic ones contained 9.6-1 

 seeds, an amount of difference of no significance. It 

 is remarkable how much more quickly the capsules 

 from the cleistogamic flowers are developed than those 

 from the perfect ones; for instance several perfect 

 flowers were cross-fertilised on April 14th, 1863, and a 

 month afterwards (May 15th) eight young cleistogamic 

 flowers were marked with threads; and when the two 

 sets of capsules thus produced were compared on June 

 3rd, there was scarcely any difference between them 

 in size. 



Viola odorata (white flowered, single, cultivated va- 

 riety). The petals are represented by mere scales as 

 in the last species; but differently from in the last, 

 all five stamens are provided with diminutive anthers. 

 Small bundles of pollen-tubes were traced from the 

 five anthers into the somewhat distant stigma. The 

 capsules produced by these flowers bury themselves in 

 the soil, if it be loose enough, and there mature them- 

 selves.* Lecoq says that it is only these latter cap- 

 sules which possess elastic valves; but I think this 

 must be a misprint, as such valves would obviously be 

 of no use to the buried capsules, but would serve to 

 scatter the seeds of the sub-aerial ones, as in the other 

 specis of Viola. It is remarkable that this plant, ac- 

 cording to Delpino,f does not produce cleistogamic 

 flowers in one part of Liguria, whilst the perfect flow- 

 ers are there abundantly fertile; on the other hand, 

 cleistogamic flowers are produced by it near Turin. 



* Vaucher says (' Hist. Phys. des See also Lecoq, 'Geograph. Bot.' 



Plantes d'Europe,' torn. iii. 1844, torn. v. 1856, p. 180. 



p. 309) that V. Jiirta and cottina f ' Bull' Opera, la Distribuzione 



likewise bury their capsules. del Sessi nelle Piante,' 1867, p. 30. 



