VIABILITY PRECEDES RIPENESS. 285 



nnripe seeds of Pisum sativum, Pliaseolus vulgaris, Vicia Faha, Ervumlens, 

 and Cytisus laburnum fail to germinate ; but as soon as these appear, 

 although the seeds have attained only half-size, they germinate. 



"Li these experiments the unripe seeds were allowed to remain on the 

 harvested plants until the leaves had become dry; then they were care- 

 fully removed with a sharp knife, and planted in rich mould, half an 

 inch below its surface, 

 " Of 20 unripe Pi'sym, 13 (65 per cent) germinated by 9th day. 



20 unripe Pliaseolus, 11 (55 j)er cent) germinated by 17th day. 

 20 unripe Vicia, 9 (45 per cent) germinated by 19th day. 

 20 unripe Ervum, 7 (35 per cent) germinated by 12th day. 

 20 unripe Cijlisus, 11 (70 per cent) germinated by 18th day. 



" These and other results were so favorable, that Seiifer planted, in 

 1822, unripe seeds of SopJiora japonica, and obtained from them five 

 hundred young plants. These plants do not ripen seeds in South Ger- 

 many." — Seiffer, reported by Kurr, Flora, 1836, p. 83. 



" At the conclusion of this paper Treviranus remarked that these re- 

 searches left it uncertain what the degree of immaturity was. For a 

 plant to possess firm cotyledons and a plumule and a radicle is to be a 

 long ways towards maturity." — Treviraxus, 1836. 



." Winter rye was harvested on June 20, three weeks before its time of 

 ripening. It was planted on June 26, together with ripe seed of the 

 year before. The ripe seed germinated on July 1, the other on June 28, 

 two days and a half earlier. At first the plants from unripe seeds were 

 weaker than the others ; but by a fortnight or so no difference could 

 be observed." — Goppert, Bot. Zeil. 1847, May 28, i. 386. 



"This was followed by a study by Cohn. 



" From the synopsis four statements are here given : — 



11. " Seeds separated from the plant, but still enclosed in the peri- 

 carp, ripen (nachi-eifen). 



14. " Viability does not coincide with ripeness, it precedes it. 



16. "In general, the plants produced from unripe seeds are not more 

 feeble than from ripe ones. 



17. " Seeds appear to germinate most readily when they have reached 

 a stage of medium ripeness. Before and after this, they germinate more 

 slowly." — Cohn, Flora, 1849, No. 32. 



NOTE II. — CONCERNING VITALITY OF SEEDS. 



" M. E.. Brown m'a dit avoir fait germer des graines de Nelumbium 

 speciosum, extraites par Lin. de I'herbier de Sloane ; c'est-a-dire ayant au 

 moins 150 ans." — De Caxdolle, Gcorjraphie Botanique raisonne, p. 542. 



" Seeds of Nelumbium (jawie) have sprouted after they had been in the 

 ground for a century." — Lyell's Second Visit to the United States, ii. p. 

 328. 



" Seeds of Datura stramonium have germinated after being buried for 

 more than a century." — Da vies, Welsh Botany, p. 23. 



Other more recent cases by Ernst are given in botanical journals for 

 1877. 



