CHAP. VIII. VIOLA. 317 



flowers contained on an average 9 '85 seeds; and 17 

 capsules from the cleistogamic ones contained 9*64 

 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 aa 

 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 

 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 

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

 cording to Delpino,t does not produce cleistogamic 

 flowers in one part of Liguria, whilst the perfect flowers 

 are there abundantly fertile ; on the other hand, 

 cleistogamic flowers are produced by it near Turin. 

 Another fact is worth giving as an instance of corre- 



* Vaucber says ('Hist. Pl.ys <les torn. v. 1856, p. 180. 

 Plantes d'Europe. torn. iii. 1841, f Sull' Opera, la Diatribuzione 



p. 309) that V. hirta and collina del Sessi nelle Piantc,' &c., 18t>7, 



likewise bury their capsules. p. 30. 

 Soe also Lecoq, ' Ge'ograph. Dot.' 



