Part 142. The dicotyl sub-class (Dicotylédones) comprises the crowfoot series (Archichlamydeae) and the bellflower series (Metachlamydeae). These agree in being made up of seed plants with the embryo having two cotyledons or dicotyledonous.1 The parts of the flower are very generally in fours or fives, seldom in threes; the leaves are mostly netted-veined; and in the stem there may be distinguished a central core of pith surrounded by a ring or rings of wood and bark. See especially Figs. 232 and 233. Stems thus constructed are called exogenous 2 or outside-growing, because new wood when formed is added on the outside of an older ring.

1 Di"cot-y-led'on-ous - Gr. dis, two; kotyledon, seed-leaf.

2 Ex-og'en-ous - Gr. exo, outside; genes, producing.