_Nucleus_, the reproductive germ in the spore.
_Obconic_, inversely conical.
_Obcordate_, like an inverted heart.
_Oblique_, slanting.
_Oblong_, longer than broad.
_Obovate_, inversely egg-shaped, broadest at the apex.
_Obtuse_, blunt or rounded.
_Ochrospore_, ochre-colored spore.
_Orbicular_, having the form of an orb.
_Order_, group of a cla.s.sification intermediate between tribe and family.
_Ostiole_, _ostiolum_, mouth of the perithecium; orifice through which the spores are discharged.
_Ovate_, egg-shaped.
_Pallid_, pale, undecided color.
_Papillate_, _papillose_, covered with soft tubercles.
_Paraphyses_, sterile cells found with the reproductive cells of some plants.
_Parasitic_, growing on and deriving support from another plant.
_Partial_, of a veil clothing the stem and reaching to the edge of the cap but not extending beyond it.
_Patent_, spreading.
_Pectinate_, toothed like a comb.
_Pedicel_, foot-stock.
_Pedicillate_, having a pedicel.
_Pelliculose_, furnished with a pellicle or distinct skin.
_Penciled_, with pencil-like hairs either on the tip or border.
_Peridium_, general covering of a puff-ball, simple or double, dehiscent or indehiscent at maturity.
_Perithecia_, bottle-like receptacles containing asci.
_Peronate_, used when the stem has a distinct stocking-like coat.
_Persistent_, inclined to hold firm, tenacious.
_Pervious_, forming an open tube-like pa.s.sage.
_Pileate_, having a cap.
_Pileoli_, secondary pilei; arising from a division of the primary pileus.
_Pileus_, the cap, receptacle, or one part of a mushroom; other parts are the stem and gills.
_Pilose_, covered with hairs.
_Pits_, depressions in cells or tubes resembling pores, applied also to hollow depressions in the surface of the cap of the morel.
_Plumose_, feathery.
_Pore_, orifice of the tubes of polypores.
_Poriform_, in the form of pores.
_Porous_, having pores.
_Powdery_, covered with bloom or powder.
_Projecting_, the anterior end jutting out beyond the margin.
_Proliferous_, applied to an organ which gives rise to secondary ones of the same kind.
_Pruinose_, covered with frost-like bloom.
_Pruniform_, plum-shaped.
_p.u.b.escent_, downy.
_Pulverulent_, covered with dust.
_Pulvinate_, cushion-shaped.
_Punctate_, dotted with points.
_Pyriform_, pear-shaped.
_Quaternate_, arranged in groups of four.