Chap. VXII. 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 markeid 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 ii^ 

 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- 



* Vauoher says ('Hist. Pliys. <les torn. v. 1856, p. 180. 



Plantes d'Euiope, torn. iii. 1844, t ' Sull' Opera, la DistribuzioM 



p. 309) that V. hirta and eollina dei Sessi nelle Piante,' &c., X867, 



likewise bury their eapsules.r- p. 30. 

 See also Lecoq, 'Ge'ograph. Bot.' 



