330 



CULINARY PLANTS. 



Chap. IX, 



years, which always came true. From the analogy of kidney-beans I 

 should have expected 8S that occasionally, perhaps at long intervals of time, 

 when some slight degree of sterility had supervened from long-continued 

 self-fertilisation, varieties thus growing near each other would have 

 crossed; and I shall give in the eleventh chapter two cases of distinct 

 varieties which spontaneously intercrossed, as shown (in a manner here- 

 after to be explained) by the pollen of the one variety having acted 

 directly on the seeds of the other. Whether the incessant supply of new 

 varieties is partly due to such occasional and accidental crosses, and their 

 fleeting existence to changes of fashion; or again, whether the varieties 

 which arise after a long course of continued self-fertilisation are weakly 

 and soon perish, I cannot even conjecture. It may, however, be noticed 

 that several of Andrew Knight's varieties, which have endured longer 

 than most kinds, were raised towards the close of the last century by 

 artificial crosses; some of them, I believe, were still, in 1860, vigorous; 

 but now, in 1865, a writer, speaking 87 of Knight's four kinds of marrows, 

 says, they have acquired a famous history, but their glory has departed. 



With respect to Beans (Faba vulgaris), I will say but little. Dr. Alefeld 

 has given 88 short diagnostic characters of forty varieties. Every one who 

 has seen a collection must have been struck with the great difference in 

 shape, thickness, proportional length and breadth, colour, and size which 

 beans present. What a contrast between a Windsor and Horse-bean ! As 

 in the case of the pea, our existing varieties were preceded during the Bronze 

 age in Switzerland by a peculiar and now extinct variety producing very 

 small beans. 89 



Potato (Solanum tuberosum). — There is little doubt about the parentage 

 of this plant ; for the cultivated varieties differ extremely little in general 

 appearance from the wild species, which can be recognised in its native 

 land at the first glance. 90 The varieties cultivated in Britain are nume- 

 rous ; thus Lawson 91 gives a description of 175 kinds. I planted eighteen 

 kinds in adjoining rows; their stems and leaves differed but little, 

 and in several cases there was as great an amount of difference between 

 the individuals of the same variety as between the different varieties. 

 The flowers vary in size, and in colour between white and purple, but 

 in no other respect, except that in one kind the sepals were somewhat 

 elongated. One strange variety has been described which always produces 

 two sorts of flowers, the first double and sterile, the second single and 

 fertile. 92 The fruit or berries also differ, but only in a slight degree. 93 



86 I have published full details of ex- 

 periments on this subject in the ' Gar- 

 dener's Chronicle,' 1857, Oct. 25th. 



87 'Gardener's Chronicle,' 1865, p. 

 387. 



88 ' Bonplandia,' x., 1862, s. 348. 



89 O. Heer, ' Die Pflanzen der Pfahl- 

 bauten,' 1866, s. 22. 



90 Darwin, 'Journal of Researches,' 

 1845, p. 285. 



91 Synopsis of the vegetable products 

 of Scotland, quoted in Wilson's ' British 

 Farming,' p. 317. 



92 Sir G. Mackenzie, in ' Gardener's 

 Chronicle,' 1845, p. 790. 



93 'Putsche und Vertuch, Versuch 

 einer Monographie der Kartoffeln,' 1819, 

 s. 9, 15. See also Dr. Anderson's ' Re- 

 creations in Agriculture,' vol. iv. p- 

 325. 



