seed (127) of a cell.

_Nucule_, same as nutlet.

_Nude_, (Latin, _Nudus_), naked. So _Nudicaulis_, naked-stemmed, &c.

_Nut_, Latin _Nux_, a hard, mostly one-seeded indehiscent fruit; as a
chestnut, butternut, acorn, 121.

_Nutant_, nodding.

_Nutlet_, a little nut; or the stone of a drupe.

_Ob-_ (meaning over against), when prefixed to words signifies
inversion; as, _Obcompressed_, flattened the opposite of the usual way;
_Obcordate_, heart-shaped, with the broad and notched end at the apex
instead of the base, 54; _Oblanceolate_, lance-shaped with the tapering
point downwards, 52.

_Oblique_, applied to leaves, &c., means unequal-sided.

_Oblong_, from two to four times as long as broad, 52.

_Obovate_, inversely ovate, the broad end upward, 53. _Obovoid_, solid
obovate.

_Obtuse_, blunt or round at the end, 54.

_Obverse_, same as _inverse_.

_Obvolute_ (in the bud), when the margins of one piece or leaf
alternately overlap those of the opposite one.

_Ocellate_, with a circular colored patch, like an eye.

_Ochroleucous_, yellowish-white; dull cream-color.

_Ocreate_, furnished with _Ocreae_ (boots), or stipules in the form of
sheaths, 67.

_Octo-_, Latin for eight, enters into the composition of _Octagynous_,
with eight pistils or styles; _Octamerous_, its parts in eights;
_Octandrous_, with eight stamens, &c.

_Oculate_, with eye-shaped marking.

_Officinal_, used in medicine, therefore kept in the shops.

_Offset_, short branches next the ground which take root, 40.

_Oides_, termination, from the Greek, to denote likeness; so
_Dianthoides_, Pink-like.

_Oleraceous_, esculent, as a pot-herb.

_Oligos_, Greek for few; thus _Oliganthous_, few-flowered, &c.

_Olivaceous_, olive-green.

_Oophoridium_, a name for spore-case containing macrospores.

_Opaque_, applied to a surface, means dull, not shining.

_Operculate_, furnished with a lid (_Operculum_), as the spore-case of
Mosses, 163.

_Opposite_, said of leaves and branches when on opposite sides of the
stem from each other (i. e. in pairs), 29, 68. Stamens are opposite the
petals, &c., when they stand before them.

_Oppositifolius_, situated opposite a leaf.

_Orbicular_, _Orbiculate_, circular in outline, or nearly so, 52.

_Order_, group below class, 178. _Ordinal names_, 180.

_Organ_, any member of the plant, as a leaf, a stamen, &c.

_Organography_, study of organs, 9. _Organogenesis_, that of the
development of