abaxial :

away from or the side of an organ facing away from the axis (ab as in abandon); for example, the lower surface of a leaf blade or petiole

adaxial :

toward the axis or the side of an organ facing toward the axis (ad as in adhere); for example, the upper surface of a leaf blade or petiole


bifid :

deeply cleft into two usually equal parts or two-lobed from the apex; for example, palms with bifid leaves or leaflet tips (e.g., Chamaedorea metallica has bifid leaves)

bipinnate :

doubly pinnate

bloom :

a white-gray waxy powder that covers a surface

boss :

expanded mass of exposed roots at the root initiation zone


costa :

mid-rib or vein

costapalmate :

a fan-shaped leaf with a midrib (costa) extending into the blade, sometimes extending far enough into the blade to cause it to curve (e.g., Sabal palmetto)

crown shaft :

a cylinder of clasping leaf sheaths toward the apex of the stem, found in some pinnate-leaved palms (e.g., Wodyetia bifurcata)


fishtail :

leaflet shape of some palms appearing like a fish tail, or as if a bite has been taken out of the leaflet, eg. Caryota (see praemorse)

floccose :

having tufts of soft, uneven hairs (e.g., Bismarckia nobilis leaves)


glaucous :

bluish-grey or -green


hastula :

a flange or collar-like flap of tissue extending from the petiole where a palmate leaf blade joins it; often seen on the upper (adaxial) surface, but may also be found on the lower (abaxial) surface in some palms


indumentum :

a covering of fine hairs or bristles

induplicate :

Most palm leaflets or leaf segments are obviously folded. If the folds create a V-shape, with the midrib lower than the margins (so that rain might fall "into a valley"), the folding is induplicate.

inflorescence :

the reproductive structure of a flowering plant, including palms, consisting of flowers and associated bracts


lanceolate :

term to describe leaves and leaflets that are longer than wide and widest below the mid-point; lance-shaped

leaf :

in palms -- the leaf blade (which is usually divided into leaflets or leaf segments), the petiole (or leaf stalk) and the sheath (which forms the attachment of the leaf to the stem)

ligule :

a distal projection of the leaf sheath

linear :

term to describe leaves and leaflets that are narrow with nearly parallel margins; like a line


marcescent :

remaining attached after becoming old and withered (e.g., aging leaves of Washingtonia palms suggest the common name, “petticoat palm”)


obdeltiod :

inversely deltoid; triangular and attached to the stem via a tip


palmate :

like the palm of a hand; fan palms have palmate leaves that are usually divided into leaf segments arising from a central point, although a fan palm may have entire leaves (e.g., Licuala grandis)

pedicel :

a floral stalk

pinnate :

like a feather; palms with pinnate leaves usually have compound leaflets attached to a rachis, although a pinnate leaf may be entire with pinnate veins (e.g., Chamaedorea metallica)

pistillate :

a flower bearing a pistil but no stamens; a “female” flower

plumose :

softly feathered

praemorse :

with a jagged edge or like a fish tail


rachis :

an extension of the petiole through the blade of a pinnate leaf to which leaflets are attached

ramenta :

irregularly shaped, thin scales, sometimes found along the abaxial midrib of a leaflet

reduplicate :

Most palm leaflets or leaf segments are obviously folded. If the folds create an upside-down V-shape, with the margins lower than the midrib (so that rain might "run off the roof"), the folding is reduplicate.

reins :

narrow strips along the margins of some pinnate leaves that peel away as the leaflets unfold; in some species, the reins are persistent and hang down long after the leaf has “opened.”


scurf :

bran-like scales (found on Phoenix roebelenii leaves, for example)

sigmoid :

resembling the Greek letter sigma or the Latin letter "s"; s-shaped

staminate :

a flower bearing stamens but no pistils; a “male” flower


tomentum :

a covering of closely matted or fine hairs on plant leaves

turbinate :

shaped like a coil; increasing in diameter from the tip to the base


waxy bloom :

a white-gray waxy powder that covers a surface

Last Updated May 2014