322 CULTIVATED PLANTS. Chap. IX. 



CHAPTER IX. 



CULTIVATED PLANTS : CEREAL AND CULINARY PLANTS. 

 PRELIMINARY REMARKS on the number and parentage of 



CULTIVATED PLANTS — FIRST STEPS IN CULTIVATION — GEOGRAPHICAL 

 DISTRIBUTION OF CULTIVATED PLANTS. 



CEREALIA. — DOUBTS on the number of species.— — -wheat : varieties 



OF — INDIVIDUAL VARIABILITY — CHANGED HABITS — SELECTION — ANCIENT 



history of THE VARIETIES.— MAIZE: GF.EAT VARIATION OF — DIRECT 



ACTION OF CLIMATE ON. 



CULINARY PLANTS. — cabbages: varieties of, in foliage and 



STEMS, BUT NOT IN OTHER PARTS — PARENTAGE OF — OTHER Sl'ECIES OF 



BRASSICA. PEAS : AMOUNT OF DIFFERENCE IN THE SH.VERAL KINDS, 



CHIEFLY IN THE PODS AND SEED — SOME V.^RIETIES CONSTANT, SOME 



HIGHLY VARIABLE — DO NOT INTERCROSS.- BEANS. POTATOES' 



NUMEROUS VARIETIES OF — DIFFERING LITTLE, E.KCEPT IN THE TUBERS — 

 CHARACTERS INHERITED. 



I SHALL not enter into so mucli detail on the variability of 

 cultivated 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 bota- 

 nists believe that several of our anciently cultivated ])lants 

 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 de- 

 scended from one species, or from several inextricably com- 

 mingled by crossing and variation. Variations often pass 

 into, and cannot be distinguished from, monstrosities ; and 

 monstrosities are of little significance for our purpose. Many 

 varieties 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 



