CHAKACTERS OOMMOK TO MONOCOTYLEDONS. 



85 



found to be marked by characters possessed by all its 

 members. The flowers of Dicotyledons were found to 

 have their parts, as a rule, in fours or fives ; those of our 

 second group have them in threes or sixes, never in fives. 

 116. Again, tlje leaves of these plants are straight- 

 veined, except in Trillium and Indian Turnip, which must 

 be regarded as exceptional, and they do not as a rule 

 exhibit the division into petiole and blade which was 

 found to characterize the Exogens. 



117. We shall 

 now compare the 

 structure of a 

 grain of Indian 



■■MM W%,M ^°^^ yiiih. that of 

 the Cucumber or 

 FTg.110. Fig. 112. Fig. 111. punipkin seed 



which we have already examined "(page 59). It will 

 facilitate our task if we select a grain from an ear which 

 has been boiled. And, first of all, let us observe that the 

 grain consists of something more than the seed. The 

 grain is very much like the achene of the Buttercup, but 

 differs in this respect, that the outer covering of the 

 former is completely united with the seed-coat underneath 

 it, whilst in the latter the true seed easily separates from 

 its covering. Eemove the coats of the grain, and what is 

 left is a whitish, starchy-looking substance, having a 

 yellowish body inserted in a hollow (Fig. 110) in the 

 middle of one side. This latter body is the embryo, and 

 may be easily removed. All tlie rest is albumen. Fig. 

 Ill is a front view of the embryo, and Fig. 112 shows a 

 vertical section of the same. The greater part of the 



Figs. 110, 111, 112.— Seotiona of a grain of Indian Corn. (Gray.) 



