Palate

the projecting part of the throat of a gaping corolla, or base of the lower lip.

Palea

the inner glume, enclosing the flower in a Grass.

Palmate

with lobes radiating from a centre like fingers of a hand.

Paludal

addicted to a marshy habitat.

Panicle

a raceme with clusters of branched flowers.

Papilionaceous

butterfly-like, as the flowers of a Pea, Vetch, etc.

Papilla

a small wart-like protuberance.

Pappus

the hairy outgrowth of the fruit in Composites.

Parasite

a plant which lives on a living plant and draws nutriment from it.

Partite

divided not quite to the base.

Patelliform

disc-like.

Patent

spreading nearly at right angles.

Pedicel

a branch from a peduncle which bears a flower.

Peduncle

flower-stalk.

Peltate

shield-shaped, with the stalk attached below or above the surface, not to the margin.

Perennial

plants that live for several years, seeding several times.

Perfoliate

when the stem is encircled by a leaf, almost or entirely.

Perianth

the outer whorls of a flower, or the calyx and corolla.

Pericarp

the seed vessel or wall of an ovary which forms a fruit.

Perigynous

when the corolla and stamens are borne on the calyx, but are not attached to the ovary.

Persistent

not falling.

Petal

the division of a corolla.

Petiole

the leaf-stalk.

Phaenogamous

furnished with stamens and pistil.

Phaenology

the recording of the time of flowering, budding of leaves, etc.

Phyllaries

the bracts of the involucre in a Composite.

Physiognomy

the general structure or characters of a floral tract.

Pilose

with stiff scattered hair.

Pinnate

with the leaflets arranged on either side of a common stalk.

Pinnatifid

when the leaf is deeply divided pin-nately almost to the midrib into narrow segments.

Pinnule

the segment of a bipinnate leaf.

Pistil

the female part of a flower, including ovary, style, and stigma.

Pistillate

flowers with pistils and without stamens.

Pitted

with depressions on the surface.

Plaited

plicate or folded.

Plant association

in a botanical formation there are groups of different species such as woodland, grassland, heath, etc. Each group is an association.

Plant community (see Community).

Plant-formation

a community of species, such as that of clays and loams, associated together by definite external characters of the habitat; an expression of certain defined conditions of life (not affected by floristic differences).

Pollarding

the removal of the crown of a tree causing branches to sprout out.

Pollen

the cells (microspores) contained in the anther.

Pollen-grain

a grain of pollen or microspore.

Pollen-sac

the sporangium containing the microspores.

Pollen-tube

the outgrowth of the pollen-grain which helps to fertilize the plant.

Pollinium

a mass of pollen-grains adhering together.

Polycarpic

seeding more than once.

Polypetalous

with separate petals.

Polysepalous

with several sepals not coherent.

Pome

a fleshy false fruit with many seeds.

Porous

when the anthers dehisce by holes.

Prickle

a hard, sharp epidermal process not woody.

Procumbent

prostrate, lying on the ground.

Prostrate

flat on the ground.

Proterandrous (Protandrous)

when the anthers ripen and dehisce before the stigma.

Proterogynous (Protogynous)

when the stigma is ripe before the anthers dehisce.

Psammophilous

addicted to a sand-soil.

Pubescent

with down closely pressed to the surface.

Pulverulent

powdery.

Pyriform

pear-shaped.

Raceme

a simple centripetal inflorescence with stalked flowers.

Rachis

the axis of a compound leaf or the central stem of several spikelets in a Grass.

Radical

springing from the crown of the root as leaves.

Ray

the outer circle of florets in a composite.

Receptacle

(1) the terminal part of the floral axis; (2) the flat, short axis of a flowerhead in Composites.

Recurved

bent back.

Reflexed

bent back (markedly so).

Reniform

kidney-shaped.

Revolute

rolled back.

Rhizome

an underground stem, with roots and leafy shoots.

Ringent

gaping, of a corolla.

Rock formations

different geological formations.

Rock-soil formations

which contribute to characterize the different rock-soils that make up a subsoil.

Rootstock

a thick, short root like a rhizome.

Rosette plants

plants that have short internodes and close-set leaves, as the Daisy.

Rostellum

the top of the pistil, in Orchids forming a beak or division between stamen and stigma.

Rotate

wheel-shaped, with short tube.

Rubble plants

developing on soil derived by the disintegration of rock by atmospheric agency, e.g. the chalk.

Runcinate

with the leaf segments turned back.

Runner

a prostrate stem rooting at intervals or at the end.

Rupestral

growing on rocks.

Sagittate

with segments like the barb of an arrow.

Samara

an indehiscent winged fruit; as the key of an Ash. Saprophyte, growing on dead or decaying animal or vegetable matter.

Saxicolous

growing on stones, walls, etc. Scabrous, rough.

Scape

a peduncle which is without leaves and radical.