Glossary of Botanical Terms - L

L

labellum
lip; one of three or five petals which is (usually) different from the others, e.g. in Orchidaceae and Stylidiaceae.
labiate
lipped; where the limb of a corolla is divided into two parts, called an upper and lower lip, the two resembling an open mouth with lips.
lacerate
jagged, as if torn.
laciniate
slashed into narrow, pointed lobes.
lamella
(plural lamellae, adjective lamellate) a thin, plate-like layer.
lamina
the blade of a leaf or the expanded upper part of a petal, sepal or bract.
lanceolate
about four times as long as broad, broadest in the lower half and tapering to the tip; narrowly ovate (sometimes, and incorrectly, used to mean narrowly elliptic; like a lance head).
lateral
attached to the side of an organ, e.g. leaves on a stem.
latex
a milky substance that exudes from such plants such as milk thistles, figs and dandelions.
latrorse
a type of anther dehiscence in which the anthers open laterally toward adjacent anthers. cf. introrse, extrorse.
lauroid
resembling Laurus, the laurel genus, particularly its leaves.
lax
loose, not compact.
leaf
an outgrowth of a stem, usually flat and green; its main function is food manufacture by photosynthesis.
leaf gap
a parenchymatous area in the stele above (distal to) a leaf trace.
leaf trace
a vascular strand connecting the stele to a leaf.
leaflets
the ultimate segments of a compound leaf.
legume
1. a fruit characteristic of the families Mimosaceae, Caesalpiniaceae and Fabaceae, formed from one carpel and either dihiscent along both sides, or indehiscent.
2. a crop species in the family Fabaceae.
3. a plant belonging to the Leguminosae (Fabaceae family).
lemma
the lower of 2 bracts enclosing a grass flower.
lenticel
a loosely packed mass of cells in the bark of a woody plant (used for gas exchange), visible on the surface as a raised powdery spot.
lepidote
covered with small scurfy scales.
liana
a woody climbing plant, rooted in the ground (both liane and liana are used).
liane
a woody climbing plant, rooted in the ground.
lignotuber
a woody swelling of the stem below or just above the ground; contains adventitious buds from which new shoots can develop, e.g. after fire.
ligulate
1. bearing a ligule.
2. strap-shaped.
ligule
1. small membranous appendage on the top of the sheath of grass leaves.
2. a minute adaxial appendage near the base of a leaf, e.g. in Selaginella.
3. extended, strap-like corolla of some daisy florets.
linear
very narrow in relation to its length, with the sides mostly parallel. See Leaf shape.
lithophytic
a plant growing on rocks; an epilithic plant.
lobe
part of a leaf (or other organ), often rounded, formed by incisions to about halfway to the midrib.
loculicidal
of a fruit, when it dehisces through the centres of loculi; cf. septicidal.
loculus
a chamber or cavity, for example, within an ovary.
lomentum
a pod-like indehiscent fruit that develops constrictions between the segments and at maturity breaks into one-seeded segments.
lunate
crescent-shaped.
lyrate
lyre-shaped; deeply lobed, with a large terminal lobe and smaller lateral ones.

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