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Term	Definition
Pubescence (adjective = pubescent)	Referring to plants with some or all of their parts covered with trichomes.
Pulvinate	Possessing pulvini.
Pulvinulus (pl. = pulvinulus, adj. = pulvinate or pulvinulate)	An enlargement at the base of the petiole or petiolule of leaves.
Pulvinus (plural = pulvini)	An enlargement of a portion of the petiole, without an apparent function (e.g., Protium, Burseraceae) or sometimes controlling the orientation of the leaf or leaflet (e.g., Mimosa polydactyla and M. pudica, Fabaceae).
Punctate	With small dots or streaks that transmit light when held against a light source, with sunken glands, or colored dots; especially easy to see in species of Myrtaceae and Rutaceae.
Punctation (adj. = punctate)	A translucent glandular dot or streak such as found on the leaves of Myrtaceae or Rutaceae or an opaque dot found in other families, such as the Lecythidaceae.
Pustule (adj. pustulate)	A small pimple-like eruption from the surface of part of a plant; e.g., from the hypanthium.
Pustule (adj. pustulate)	A small pimple-like eruption from the surface of part of a plant; e.g., from the hypanthium.
Pyrene	In the Burseraceae, the part of the fruit surrounding a seed or seeds that is derived from the endocarp and is sometimes surrounded by a pseudaril. Similar to a stone but we restrict stones to only drupes or drupelets with a single seed.
Pyxidium, pyxidiate	A capsular fruit with circumscissile dehiscence.
Quaternary vein	Referring to fourth order leaf veins which are intermediate in diameter between tertiary and quinary veins.
Raceme	An indeterminate inflorescence with a single axis, the flowers borne on pedicels of more or less equal length, and the uppermost flower the youngest. Compare with spike.
Rachilla	The axis of a spikelet of a Cyperaceae or a Poaceae along which are placed the florets.
Rachis (alt. spelling = rhachis)	The axis of a compound leaf (excluding the petiole) or of an inflorescence (excluding the peduncle); in legumes, that part of the leaf axis bearing leaflets of any order.
Rachlla	A secondary axis of an inflorescence; e.g., the axis of the spikelet in Poaceae or the axis that bears the flowers in Arecaceae.
Radial thickenings	A series of protuberances arranged in a spoke-like pattern around the top of the supracalycine zone just outside the line of opercular dehiscence.
Radially symmetrical flower	A flower, capable of being divided, by more than one line passing through the middle of the flower, into two equal parts that are mirror images of one another; e.g., in Gustavia (Lecythidaceae), species of Myrtaceae, and species of Rubiaceae. Same as actinomorphic, polysymmetric, and regular flowers and opposite of zygomorphic, monosymmetric, bilateral, and irregular flowers. This term can refer to other plant parts as well.
Radiate capitulum (head)	Inflorescence of Asteraceae with marginal ray flowers and central disk flowers.
Radicle	The lower portion of the embryo that develops into the root. Same as hypocotyl.
Rain forest	A low, large tree dominated forest found from sea level to around 500 meters in Latin America. Dominant trees families are members of the Burseraceae, Chrysobalanceae, Lecythidaceae, Moraceae, Sapotaceae etc. but the composition of the forest can vary geographically, for example, the rain forests of eastern Brazil are sometimes dominated by species of Myrtaceae. The largest trees in neotropical rain forests usually do not exceed 65 meters in height. True rain forest does not have a marked tree season but currently the rain forest concept does include some forests with short dry seasons.
Ramet	An individual part of a clone, e.g., an offshoot.
Ramiflorous	Producing flowers on leafless branches or leafless parts of stems; a special type of cauliflory. Compare with cauliflorous.
Ramiflorous inflorescence	Refers to inflorescences that arise from the branches. Inflorescences that arise from the trunk are called cauliflorous. The branches can be much smaller in diameter than those shown here.
Ramiflorous inflorescence	Refers to inflorescences that arise from the branches. Inflorescences that arise from the trunk are called cauliflorous. The branches can be much smaller in diameter than those shown here.
Raphe	A ridge on a seed formed by the fusion of the funicle to the seed coat, usually indicated by a scar after the seed has been formed.
Raquis	Eje de una hoja compuesta (excluido el peciolo), o de una inflorescencia (excluido el pedúnculo); por ejemplo, en las Leguminosas, el raquis es la parte del eje de las hojas que sostiene a las hojuelas
Ray flower	A zygomorphic flower with a straplike corolla found in Asteraceae. Compare with disk flower.
Recepticle	The thickened part of the pedicel from which the flower organs or the fruits arise. In some accessory fruits, for example the pome and strawberry, the receptacle gives rise to the edible part of the fruit.
Receptive stigma	The time when pollen grains placed on the stigma by a pollinator are able to germinate and, thus, the nuclei they contain can potentially fertilize the egg which then has the chance to grow into an embryo, then become a seedling, and finally a reproductive plant itself.
Recurved	Curved backward.
Reed stem	In some Orchids (e.g. Epidendrum), this term refers to having stems that are long and relatively slender, commonly with leaves scattered along the stem.
Reflexed	Abruptly bent backward or downward.
Regular flower	A flower, capable of being divided, by more than one line passing through the middle of the flower, into two equal parts that are mirror images of one another; e.g., in Gustavia (Lecythidaceae), species of Myrtaceae, and species of Rubiaceae. Same as actinomorphic, polysymmetric, and radially symmetrical flowers and opposite of zygomorphic, monosymmetric, bilateral, and irregular flowers. This term can refer to other plant parts as well.
Reniform	Kidney-shaped.
Repent	Creeping flat along the ground, usually referring to stems growing along the ground that produce roots at their nodes. Same as prostrate.
Replum	A thin membrane that runs from one side of the fruit to the other side of the fruit in many Brassicaceae that persists after the fruits have dehisced and the seeds have been dispersed, i.e., it is the partition between the two compartments or locules of the fruits.
Reproductive biology	In this glossary, all terms that refer to asexual and sexual reproduction in the broadest sense.
Respiration	In plants, the process of oxidizing sugars to obtain energy for growth and reproduction. This yields carbon dioxide and water as byproducts.
Restinga	Portuguese term referring to a diverse array of vegetation found on sandy soil in a narrow band along the Brazilian coast between the high-tide mark and taller forests farther inland.
Resupinate	Turned 180° in development; e.g., flowers of the Orchidaceae in which the lip originates in the uppermost position but twists 180° so it facing downward at anthesis. Most orchids have resupinate flowers.
Reticulate	Netted, like the veins of many leaves.
Reticulate tertiary venation	Tertiary venation anastomosing with other tertiary veins or with the secondary veins (Hickey, 1973)
Reticulate venation	Referring to the venation of a leaf which forms a network.
Retrorse	Directed downward or backward. Opposite of antrorse.
Retuse	Notched slightly at the apex.
Revolute	With the margin inrolled toward the abaxial surface. Compare with involute.
Rhizome	A prostrate stem below the ground that sends off rootlets and vertical stems or leaves; in the Poaceae, lateral underground stems that collectively constitute a “sod” from which leafy stems emerge.
Rimose	Fissured or cracked, as the bark of some trees.
Ring nectary (= nectary ring-like)	A raised, circular ridge found between the attachment of the androecium and the base of the style that produces nectar.
Riparian	Referring to plants and animals that growi or live along streams or rivers.
Riverine	See riparian.
Rosette	An arrangement of leaves radiating from the base of the stem and usually placed close to the ground.
Rostellum (plural = rostella)	The portion of the stigma of some Orchidaceae that separates the anther from the fertile part of the stigma and aids in gluing the pollinia to the pollinators; a small beak.
Rosulate	Referring to a cluster of leaves arranged in a rosette.
Rounded	Referring to a leaf blade that is curved at the apex with an angle greater than 90 degrees at the point where the two sides meet.
Rugose (diminutive = rugulose)	Having a wrinkled surface.
Rugose hypanthium	Refers to a hypanthium with a wrinkled surface.
Ruminate endosperm	Testa or seed coat folded into the endosperm; e.g., that of many species of Annonaceae, Myristicaceae, and Arecaceae.
Runner	A slender stolon that periodically roots to produce an offshoot of the original plant.
Running buttress	A thick, rounded buttress that extends along the ground several meters or more from the trunk. Compare with flying buttress and plank buttress.
Rupicolous	Dwelling among rocks.
Sagittate	Shaped like an arrowhead.
Salient	Raised from the surface, usually referring to veins of leaves.
Salient	Markedly raised above the surface of an organ; e.g., the midrib on the abaxial side of the leaf blade in most species of neotropical Lecythidaceae.
Salverform	Referring to the shape of a sympetalous corolla in which the tube is slender and the lobes are abruptly spreading and flat. Same as hypocrateriform and more frequenly used by authors than that term.
Samara	An indehiscent, winged fruit; e.g., those of Machaerium spp. and Vataireopsis spp. (Fabaceae).
Sap	A free-flowing exudate that can be translucent, colorless, yellow, orange, or red. It is not as thick and viscous as latex.
Saprophyte	A heterotrophic plant that is without chlorophyll, lives on decayed plant material, and usually depends on a symbiotic relationship with a fungus to obtain food.
Sapwood	The outer functional part of the xylem, i.e., the living part of the xylem that transports water and nutrients to the leaves. Same as soft bast.
Sarcotesta	Estructura carnosa que se origina en el tegumento y recubre a la semilla. Comparar con eleosoma y arilo.
Sarcotesta	A layer arising from the integument of a seed. Compare with aril and elaiosome.
Sarcotesta	A fleshy layer of the seed coat that attracts animals and aids in seed dispersal.
Savanna (also spelled savannah)	A type of vegetation with scatttered shrubs and relatively small, often contorted trees with thick bark and grasses and sedges dominating the understory.
Saxicolous	Referring to a plant that prefers growing in rocky habitats.
Scalariform	Arranged as in the rungs of a ladder; ladderlike.

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