Merous, from the Greek for part; used with numeral prefix to denote the number of pieces in a set or circle: as Monomerous, of only one, Dimerous, with two, Trimerous, with three parts (sepals, petals, stamens, &c.) in each circle.

Mesocarp, the middle part of a pericarp, when that is distinguishable into three layers, [120].

Mesophlœum, the middle or green bark.

Micropyle, the closed orifice of the seed, [110], [126].

Microspore, the smaller kind of spore when there are two kinds, [161].

Midrib, the middle or main rib of a leaf, [50].

Milk-vessels, [135].

Miniate, vermilion-colored.

Mitriform, mitre-shaped: in the form of a peaked cap, or one cleft at the top.

Moniliform, necklace-shaped; a cylindrical body contracted at intervals.