Chap. IX. PEAS. 345 



This latter plant, in its cultivated state, differs in scarcely any 

 character from the wild English carrot, except in general luxuri- 

 ance and in the size and quality of its roots; but ten varieties, 

 differing in the colour, shape, and quality of the root, are cultivated 

 in England and come true by seed. 80 Hence with the carrot, as 

 in so many other cases, for instance with the numerous varieties 

 and sub-varieties of the radish, that part of the plant which is 

 valued by man, falsely appears alone to have varied. The truth 

 is that variations in this part alone have been selected ; and the 

 seedlings inheriting a tendency to vary in the same way, analogous 

 modifications have been again and again selected, until at last 

 a great amount of change has been effected. 



"With respect to the radish, M. Carriere, by sowing the seed of 

 the wild Eaphanus ruphanistrum in rich soil, and by continued 

 selection during several generations, raised many varieties, closely 

 like the cultivated radish (B. sativus) in their roots, as well as the 

 wonderful Chinese variety, B. caudatus : (see ' Journal d' Agriculture 

 pratique/ t. i.. 1869, p. 159 ; also a separate essay, f Origine des 

 Plants Domestiques,' 1869.) Raphanus raphauislrum aiid sativus 

 have often been ranked as distinct species, and owing to differences 

 in their fruit even as distinct genera ; but Professor Hoffman (' Bot. 

 Zeitung,' 1872, p. 482; has now shewn that these differences, re- 

 markable as they are, graduate away, the fruit of B. caudatus 

 being intermediate. By cultivating B. raphanistrum during several 

 generations (ibid., 1873, p. 9), Professor Hoffman also obtained plants 

 bearing fruits like those of B. sativus. 



tea (Pisum sativum). — Most botanists look at the garden-pea 

 as specifically distinct from the field-pea (P. arvense). The latter 

 exists in a wild state in Southern Europe; but the aboriginal 

 parent of the garden-pea has been found by one collector alone, 

 as he states, in the Crimea. 81 Andrew Knight crossed, as I am 

 informed by the Eev. A. Fitch, the field-pea with a well-known 

 garden variety, the Prussian pea, and the cross seems to have been 

 perfectly fertile. Dr. Alefeld has recently studied 82 the genus 

 with care, and, after having cultivated about fifty varieties, concludes 

 that certainly they all belong to the same species. It is an interest- 

 ing fact already alluded to, that, according to 0. Heer, 83 the peas 

 found in the lake-habitations of Switzerland of the Stone and 

 Bronze ages, belong to an extinct variety, with exceedingly small 



that he took seed from a wild carrot, 81 Alph. De Candolle, 'Geograph. 



growing far from any cultivated Ian i, Bot.,' 960. Mr. Bentham (' Hort. 



and even in the first generation the Journal, ' vul. ix. (1855), p. 141) 



roots of his seedlings differed in being believes that garden and field peas 



spindle-shaped, longer, softer, and less belong to the same species, and in this 



fibrous than those of the wild plant. respect he differs from Dr. Targioni. 

 From these seedlings he raised several 82 ' Botanische Zeitung,' 1860, s. 



distinct varieties. 204. 



80 Loudon's ' Encvclop. of Garden- 83 ' Die Pflanzen der Pfahlbauten, 



ug,' p. 835. 1865, s. 22. 



16 



