118 OBJECT LESSONS IN BOTANY. 
often, also, without stems. Hence we may say of the Cryp- 
togams that they are not only flowerless, but seedless, and 
often leafless and stemless. 
252. We will now dismiss the Cryptogams for the present, 
and consider the Flowering Plants (Phanogams), as one sub- 
kingdom ;—how shall this be divided? Every one notices a 
striking difference between plants with parallel-veined leaves 
and those with net-veined leaves. The former have their 
flowers three-parted, while the latter have their flowers two, 
four, or five-parted, &c.,—the former have seeds one-lobed 
(monocotyledoned, Less. 15), the latter, two-lobed (dicotyle- 
doned, Less. 15). Let us, then, divide the Phenogamia into 
two provinces ; as Nature has already done. 
a 
Fig, 359. Cross-section of an exogenous stem (Elm), of two years growth: 1, the 
pith; 2, 8, two layers of wood; 4, the bark. F%g. 360. Cross-section of an endoge- 
nous stem (Corn), showing no distinction of layers. 
253. We may eall these two provinces severally, the Exo- 
cerns and the ExpogEns :—two Greek words denoting outside 
growers, inside-growers, referring to their modes of growth. 
254. Now, taking such an Exogen as the Apple-tree, and 
such an Endogen as the Indian Corn, we may distinguish 
them thus: The Exogen has its wood, if any, arranged in con- 
centric rings, or layers, as seen in Fig. 360 ;—the outer ring 
252. Show how the Flowering Plants are divided. 253. Please give the 
character of an Exogen; an Endogen. Meaning of these two words ? 
