Dictionary

Word	Meaning
Obtuse	If referring to a leaf, a leaf with a rounded or blunt apex.
Ochreous	Ochre-coloured, or a light brownish-yellow.
Operculum	A covering lid over the flower, breaking off to expose the reproductive parts, as in the flowers of Eucalyptus species.
Opposite	In pairs, opposite one another. If referring to leaves, in pairs on a node, on opposite sides of stem.
opposite leaves	Leaves placed opposite one another on the stem.
Orbicular	Flat and approximately circular.
Organelle	A small organ within a cell, such as a chloroplast.
Osmosis	Spontaneous diffusion of water or other solvents through a semi-permeable membrane, from a region of higher solute concentration to a region of lower concentration, while blocking unwanted dissolved substances.
Ostiole	A small opening in a fig, or syconium, located at the opposite end to the stalk. The ostiole provides access for pollinating wasps to enter the syconium.
Ovary	The chamber at the base of the style that contains carpels, each of which contains ovules, which become seeds after fertilisation. The style bears the stigma. A superior ovary is located above the petals, and the stamens are attached below its base. An inferior ovary is within the swollen receptacle, below the sepals and petals.
Ovate	If referring to a leaf, being widest in the lower half, toward the petiole, or egg-shaped. See obovate.
Ovoid	If referring to a leaf, being widest in the lower half, toward the petiole, or egg-shaped. See obovate.
Ovule	The minute structure within the ovary that contains an egg cell which, if fertilised, becomes the seed. An ovary may contain one or many ovules.
Pachycaul	A term used for succulent plants that accumulate moisture and nutrients in the root-to-stem section of the plant, creating a thick trunk, disproportionate to the size of the plant.
Palmate	In compound leaves, when all leaflets radiate from one central point at the end of the petiole. The term is also used for 5-lobed simple leaves, shaped like the palm of an open hand with the lobes radiating outward. Lobed simple leaves have deeply indented margins. Refer to digitate.
Palmately veined	Several primary veins of approximately equal thickness radiating from a single point at the base of the leaf, where the petiole attaches. See Multi-veined.
Panicle	A branched inflorescence in which a central stem develops consecutive side branches, which also branch further, each of which carry two or more flowers. The central stem bears no flowers. A panicle is an inflorescence.
Papillose	Bearing many small and soft nipple-like projections, called Papilla.
Pappus	The tuft of hairs on each seed, which assists in dispersal by wind.
Paripinnate	A pinnate leaf with an even number of leaflets. See imparipinnate.
Pedicel	The stalk of a single flower, at the end of which is the receptacle, on which the floral parts are carried. Refer to peduncle.
Peduncle	The unbranched stalk of a compound inflorescence, ie. a shoot bearing multiple flowers. A fig encloses many flowers, and its stalk is therefore called a peduncle. The term peduncle is also used, in a general sense, for a flower stalk bearing either a solitary flower or an inflorescence. Refer to pedicel.
Peltate	Of a leaf, having the petiole attached to the leaf blade below, not to the margin of the leaf. Peltate leaves usually have a roundish shape.
Penninerved	With pinnately arranged veins, or nerves arranged on each side of the midrib.
Perennial	Living for several or many years.
Perianth	The collective term for calyx and corolla of a flower. The term is derived from Greek words translated as peri, 'around' and anthos, 'flower'.
Perigynous	Referring to flowers in which the sepals, petals and stamens are fused at the base to form a cup-shaped structure called a hypanthium or floral tube.
Persistent	The retention of plant structures after their normal purpose has been fulfilled. Caducous refers to falling early, and deciduous to falling seasonally.
Perulae	The scales of a leaf bud..
Perulate	Refers to one of the scales of a leaf bud.