edullary rays_, 13.

_Membranous._ Thin and rather soft, and more or less translucent, 23.

_Midrib._ The central or main rib of a leaf, 19.

_Monoecious._ With both pistillate and staminate flowers on the same
plant, 25.

_Monopetalous._ With the corolla more or less grown together at the
base; gamopetalous, 25.

_Mucronate._ Tipped with a short abrupt point, 22.

_Multiple roots_, 9.

_Nerved._ Parallel-veined, as the leaves of some trees, 20.

_Netted-veined._ With branching veins, forming a network as in the
leaves of most of our trees, 20.

_Node._ The part of a stem to which a leaf is attached, 18.

_Nut._ A hard, unsplitting, usually one-seeded fruit, 27.

_Nutlet._ A small nut.

_Obcordate._ Heart-shaped, with the stem at the pointed end, 21, 22.

_Oblanceolate._ Lanceolate, with the stem at the more pointed end, 21.

_Oblong._ Two to four times as long as wide, with the sides somewhat
parallel, 20.

_Oblique._ Applied to leaves when the sides are unequal, 21.

_Obovate._ A reversed ovate, 21.

_Obovoid._ A reversed ovoid; an egg form, with stem at the smaller end.

_Obscurely._ Not distinctly; usually needing a magnifying-glass to
determine.

_Obtuse._ Blunt or rounded at tip, 22.

_Obvolute_, 34.

_Odd-pinnate._ Pinnate, with an end leaflet, 20.

_Once-pinnate._ A compound leaf, with but a single series of leaflets
along the central stem, 19.

_Opposite._ With two leaves on opposite sides of a stem at a node, 18.

_Orbicular._ Circular in outline, 20.

_Oval._ Broadly elliptical, 20.

_Ovary._ The part of the pistil of a flower containing the ovules or
future seeds.

_Ovate._ Shaped like a section of an egg, with the broader end near the
stem, 21.

_Overlapping._ One piece spreading over another.

_Ovoid._ Ovate or oval in a solid form, like an egg.

_Ovules._ The parts within the ovary which may form seeds, 25.

_Palmate._ A compound leaf, with the leaflets all starting from the end
of the petiole, 19.

_Palmately lobed_, 22.

_Palmately veined._ With three or more main ribs, or veins of a leaf,
starting from the base, 20.

_Panicle._ An open, much branched cluster of flowers or fruit, 26.

_Pappus._ The down, hairs, or teeth on the end of the fruit in
Compositae, as the thistle-down.

_Parallel-veined._ With the veins of the leaf parallel; nerved, 20.

_Parted._ Edge of a blade separated three fourths of the distance to the
base or midrib, 23.

_Pedice