CHAr. IX. CULTIVATED PLANTS. 305 



CHAPTER IX. 



CULTIVATED PLANTS : CEREAL AND CULINARY PLANTS. 

 PRELIMINARY REMARKS on the number and parentage op cultivated 



PLANTS — PIRST STEPS IN CULTIVATION — GEOGRAPHICAL DISTRIBUTION OP 

 CULTIVATED PLANTS. 



CEREALIA. — doubts on the number op species. wheat : varieties op 



— INDIVIDUAL VARIABILITY — CHANGED HABITS — SELECTION — ANCIENT HISTORY 



OP THE VARIETIES. MAIZE : GREAT VARIATION OF — DIRECT ACTION OP 



CLIMATE ON. 



OULINARY PLANTS. — cabbages : varieties of, in foliage and stems, but 



NOT IN OTHER PARTS — PARENTAGE OP — ■ OTHER SPECIES OF BRASSICA. 



PEAS : AMOUNT OF DIFFERENCE IN THE SEVERAL KINDS, CHIEFLY IN THE PODS AND 

 SEED — SOME VARIETIES CONSTANT, SOME HIGHLY VARIABLE — DO NOT INTERCROSS. 



BEANS. POTATOES : NUMEROUS VARIETIES OF — DIFFERING LITTLE, EXCEPT 



IN THE TUBERS — CHARACTERS INHERITED. 



I shall not enter into so much detail on the variability of culti- 

 vated plants, as in the case of domesticated animals. The 

 subject is involved in much difficulty. Botanists have generally 

 neglected cultivated varieties, as beneath their notice. 'In several 

 cases the wild prototype is unknown or doubtfully known ; and 

 in other cases it is hardly possible to distinguish between escaped 

 seedlings and truly wild plants, so that there is no safe standard 

 of comparison by which to judge of any supposed amount of 

 change. Not a few botanists believe that several of our anciently 

 cultivated plants have become so profoundly modified that it is 

 not possible now to recognise their aboriginal parent-forms. 

 Equally perplexing are the doubts whether some of them are 

 descended from one species, or from several inextricably com- 

 mingled by crossing and .variation. Variations often pass into, 

 .and cannot be distinguished from, monstrosities; and mon- 

 strosities are of little significance for our purpose. Many varie- 

 ties are propagated solely by grafts, buds, layers, bulbs, &c, and 

 frequently it is not known how far their peculiarities can be 

 transmitted by seminal generation. Nevertheless some facts of 

 value can be gleaned j and other facts will hereafter be incident- 



VOL. I. 



