PLANTS CULTIVATED FOR THEIR STEMS OR LEAVES. 95 



It is becoming equally troublesome in Chili.^ It is not 

 asserted that the artichoke has anywhere been naturalized 

 in this manner, and this is another sign of its artificial 

 origin. 



Lettuce — Latuca Scariola, var. sativa. 



Botanists are agreed in considering the cultivated 

 lettuce as a modification of the wild species called Latuca 

 Scariola? The latter grows in temperate and southern 

 Europe, in the Canary Isles, Madeira,^ Algeria,^ Abys- 

 sinia/ and in the temperate regions of Eastern Asia. 

 Boissier speaks of specimens from Arabia Petrea to 

 Mesopotamia and the Caucasus.^ He mentions a variety 

 with crinkled leaves, similar therefore to some of our 

 garden lettuces, which the traveller Hausknecht brought 

 with him from the mountains of Kurdistan. I have a 

 specimen from Siberia, found near the river Irtysch, and 

 it is now known with certainty that the species grows in 

 the north of India, in Kashmir, and in Nepal.'' In all these 

 countries it is often near cultivated ground or among 

 rubbish, but often also in rocky ground, clearings, or 

 meadows, as a really wild plant. 



The cultivated lettuce often spreads from gardens, 

 and sows itself in the open country. No one, as far as I 

 know, has observed it in such a case for several genera- 

 tions, or has tried to cultivate the wild L. Scariola, to 

 see whether the transition is easy from the one form to 

 the other. It is possible that the original habitat of the 

 species has been enlarged by the diftlision of cultivated 

 lettuces reverting to the wild form. It is known that 

 there has been a great increase in the number of culti- 

 vated varieties in the course of the last two thousand 



» Cl. Gay, Flora Chilena, iv. p. 317. 



"^ The author who has gone into this question most carefully is BischofF, 

 in his Beitrdge zur Flora Deutschlands unci der Schweitz, p. 184. See 

 also Moris, Flora Sardoa, ii. p. 530. 



^ Webb, Phytogr. Ganariensis, iii. p. 422 ; Lowe, Flora of Madeira, 

 p. 544. 



* Munby, CataL, edit. 2, p. 22, tinder the name of L. sylvestris, 



^ Schweinfurth and Ascherson, Aufzahlung, p. 285. 



« Boissier, Fl. Orient., iii. p. 809." 



" Clarke, Compos. Indices, p. 263. 



