PHANEROGAMIA. 241 
which lies between the inner solid (woody) mass and the outer softer 
portion. 
510. The Angiosperms are readily separated into two 
sub-classes, as follows: 
Sub-Class I. Monocotyledones (the Monocotyledons).— 
The first leaves produced by the embryo are alternate; 
the endosperm is usually large and the embryo small. 
Sub-Class II. Dicotyledones (the Dicotyledons).—The 
first leaves of the embryo (cotyledons) are opposite; the 
endosperm is very often rudimentary or entirely wanting, 
and the embryo is generally large. 
Fia. 136.—Longitudinal section of the seed of Indian Corn. c, adherent wall 
of the ovary; n, remains of the style; sf, base of the ovary (all the remainder 
of the figure is the true seed); eg, ew, endosperm; sc, ss, cotyledon; e, its epi- 
deniqias 1s young.leaves; w, the main root; w’, roots springing from the stem. 
Magnified 6 times. 
Sus-Cuass I. Tar Monocorytepons (Monocotyledones). 
511. The first leaves of the embryo are alternate; hence 
we say that they have one cotyledon. The yenation of the 
