Prickle

a more or less conical elevation of the substance of the bark, hard and sharp-pointed.

Prismaiical

approaching the form of a prism, presenting angles disposed longitudinally.

Procumbent

lying upon or trailing along the ground.

Prostrate

procumbent.

Pubescence

elevated extensions of the cellular tissue of the epidermis, assuming the character of soft downy hairs.

Pubescent

furnished with pubescence.

Pulp

soft and juicy tissue.

Quadrangular

approximating to the form of a quadrangular prism.

Quaternate

Quaternary, having the parts arranged by fours.

Quinate

Quinary, having the parts arranged by fives, as the five petals of a buttercup, the five leaflets of a digitate leaf, etc.

Raceme

a form of inflorescence, where the flowers are furnished with pedicels arranged at intervals upon a common axis.

Racemose

arranged in racemes.

Radiant

Radiate, arranged like rays spreading from a common centre.

Radical

proceeding from a point close to the summit or crown of the root.

Ray

the outer florets in the flower-head of Composites; the outer flowers, when differently formed from the inner, in umbels; also the branches of an umbel.

Receptacle

a part which bears or receives other parts, commonly applied to that which bears the flowers, as the expanded top of the peduncle of a dandelion, the inner surface of a fig, etc.

Recurved

bent backward.

Reflex

Reflexed, very much curved backwards.

Regular

uniform in structure or condition, as where subordinate parts of the same kind closely resemble each other, and are symmetrically arranged.

Remote

thinly set on the axis.

Reniform

kidney-shaped, that is, like a longitudinal section through a kidney.

Reticulate

resembling network.

Retuse

having a slight depression or sinus at the apex.

Rhizome

a prostrate or subterranean stem, from which roots are emitted, and scaly leaves or branches given off at the knots.

Rhomboid

Rhomboidal, rudely approximating to the form of a rhombus, that is to say, a quadrangular figure (not a square) whose sides are equal.

Rib

any strongly-marked nerve in the leaf, but more especially the central longitudinal one.

Ribbed

having one or more strongly marked nerves, proceeding from the base to the apex:

Ridge

an elevated line on the carpels of Umbellifers, of which some are primary and some secondary.

Rigid

almost or quite without flexibility.

Ringent

applied to bilabiate corollas whose lips are widely separate.

Root-stock

a subterranean or prostrate stem, which emits roots from its lower surface.