Glossary - general

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Labelliform – lip-shaped

Labellum – (1) (Orchidaceae) the lowest (median) tepal of the inner whorl, usually larger and different in shape from the two lateral inner tepals; (2) (Cannaceae) larger of the three petaloid stamens in the flowers of Canna

Lacerate – ‘torn’ at the margin, irregularly lobed, as if torn

Lacerate aril – consisting of three or four coarse hair-like outgrowths

Laciniate – cut into slender lobes or drawn-out teeth

Lacinula – tiny lobe

Lacuna (of protoxylem) – a space surrounded by parenchyma cells in the protoxylem of a vascular bundle; appearing in some plants after the protoxylem has ceased to function, after these elements have been stretched and torn, thus forming the cavity

Lacunose – perforated with holes

Lageniform – bottle-shaped, urn-shaped – see also Urceolate

Lamellae – thin plates, membranes

Lamellate endexine – consisting of a number of horizontal lamellae (as seen in cross-section)

Lamellate medulla – medulla (pith) chambered by a number of cross-partitions

Lamelliform – with thin plates stacked on top of or next to each other

Lamina – expanded part, blade, of leaf or petal

Laminar placentation – superficial placentation; the ovules occupy the side portions of the inner face of the carpel or are scattered over almost the entire surface (rarely occupying only its back side)

Laminar-diffuse placentation – the ovules are scattered over almost the entire adaxial surface of the carpel

Laminar-dorsal placentation – the ovules are attached pseudo-medially, occupying the back of the carpel

Laminar-lateral placentation – the ovules occupy the side portions of the adaxial surface of the carpel between the median and the lateral veins

Laminar-median placentation – the ovules are attached in the median (middle) of the carpel, but not along the margins (i.a. in Cabombaceae and Ceratophyllaceae)

Laminate leaves – with an expanded blade (as opposed to grass-like)

Laminula – tiny blade

Lanate – with interwoven long woolly hairs

Lanceolate – narrowly ovate and tapering to a point at the apex

Lanuginose, lanuginous – woolly

Lateral – on or at the side or margin; e.g. lateral leaflets, those flanking the central leaflet

Lateral pits – see Intertracheary pits

Lateral placentation – see Laminar-lateral placentation

Laterally – on or at the side or margin

Laterocytic stomata – with three or more distinct subsidiary cells partially (not at the apex or the base) surrounding the guard cells

Latex – milky juice, often sticky

Laticifer – an elongated secretory cell which occurs in vegetative (and sometimes reproductive) organs and produces latex and rubber as secondary metabolites; laticifers may be articulated, i.e. composed of a series of fused cells, or non-articulated, consisting of a single elongate cell

Laticiferous – latex-bearing

Latrorse anther – dehiscing towards the side, towards other anthers and not towards or away from the central floral axis

Latrorsely – towards or along the sides

Lax – loose – Opposite: congested

Layered crown – with several parallel whorls or layers of branches

Leaf – chlorophyll-bearing lateral outgrowth (actually a modified branch-system) from a stem or branch

Leaf gap – a space in the stem/branch through which the leaf grows; the leaf is connected to the stem/branch by the leaf trace, which grows through the leaf gap; the leaf gap is a break (discontinuity) in the vascular tissue of a shoot above the point of attachment of a leaf trace; it exists in the nodal region as a gap in the continuity of the primary vascular cylinder above the level at which a leaf trace diverges towards a leaf; the gap is filled with parenchyma

Leaf sheath – part of leaf stalk enveloping the stem and running concurrently with it for some distance

Leaf trace – see Leaf gap

Leaflet – one (expanded) part of a compound leaf

Legume – (1) the fruit pod of the Fabaceae, derived from a single carpel, usually opening along one or both sutures into two halves, usually dry; (2) colloquial term used by botanists for any member of the Fabaceae (Leguminosae)

Lemma – the outermost of two bracts enclosing the flower in Poaceae

Lens (of seed) – lateral depression or bulge, mainly in Fabaceae

Lenticellate – with lenticels

Lenticels – corky eruptions on the bark that allow gas exchange

Lenticular – a three-dimensional body that is circular in section and convex on both sides

Lepidote – clothed on the surface with small scales

Leptocaul habit – with slender, highly branched stem – Opposite: pachycaul

Leucoanthocyanin – natural colouring pigment in plants; white and blue/red colour

Liana, liane – woody climber, supported by other vegetation

Lianescent shrub – with climbing branches behaving like lianas

Libriform fibre – a very long and thin xylem fibre with simple pits; libriform fibres, which resemble phloem fibres, are longer than the fibre tracheids and have thicker cell walls with a slit-like simple pit; libriform fibres conduct organic nutrients (carbohydrates etc.)

Ligneous – woody

Lignified – referring to a herbaceous structure that has become woody

Lignotuber – a woody swelling at the stem base or on underground stems below or just above the soil surface; the lignotuber contains adventitious buds from which new shoots develop if the top of the plant is cut or burnt

Ligulate – (1) strap-shaped; (2) with a ligule; (3) in Asteraceae inflorescences, denoting the presence of florets with a ligule

Ligule – (1) a distal projection of the leaf sheath (i.a. in Poaceae); (2) (Asteraceae) the five-toothed strap-shaped floret type in Cichorieae

Limb – the upper, usually expanded, flat part of the calyx or corolla (especially if united into a tube below)

Limen – a floral disc, e.g. in Passifloraceae

Linea lucida (of seeds) – a layer in the testa and/or tegmen of some plants near the surface in the upper part of the palisade layer; Malpighian cells usually possess a linea lucida, which is a zone of the cell that differs in its light refraction and therefore appears brighter than the rest

Linear – of two-dimensional structure, narrow and much longer than wide, with parallel margins

Lineate – marked with thin parallel lines

Lingulate – tongue-shaped

Lip – (1) one of the two divisions of a gamosepalous calyx or a zygomorphic corolla, when this is divided into an upper (posterior) and lower (anterior) portion; (2) (Orchidaceae) labellum of an orchid flower, the lowest inner tepal of an orchid flower, usually larger and different in shape from the two lateral ones

Lithocyst – cell containing a granule of calcium carbonate, a cystolith, formed on an intrusion of the cell wall

Lithophytic species or plant – growing on rock

Littoral – growing along the sea or lake shore

Lobe – a division to about halfway of any organ; more specifically, free part of the calyx or corolla, as distinct from the lower, fused part

Lobed, lobate – divided into lobes; a flat shape split in two or more subdivisions

Lobulate – with small lobes

Lobule – small lobe

Locellate – divided into small secondary compartments

Locellate anther – with secondary compartments delimited by transverse septa

Locellus – a secondary compartment of, e.g., a unilocular ovary or an anther, formed by secondary transverse septa

Locular – with cavities or compartments, usually of ovaries and fruits; unilocular: one-celled; bilocular: two-celled

Loculus (pl. loculi), locule – (1) the cavity of the carpel in which the ovule(s) are borne; (2) the compartment of an anther in which the pollen grains are borne

Loculicidal capsule – when a ripe capsule splits into the cells, i.e. not at the lines of junction between the locules (i.e., septa), but along the midrib or dorsal suture (interseptal radii); dehiscing along lines down the centres of the outer walls of the loculi or down the interplacental radii (between the placentae) when the placentation is parietal

Locusta – see Spikelet

Lodicules – (Poaceae) minute scales possibly representing the modified perianth

Lomentaceous – bearing a lomentum; resembling a lomentum

Lomentum, loment – a flat legume fruit, constricted between each seed and falling apart at the constrictions into single-seeded units

Longitudinal – in the direction of the main axis – Opposite: transverse

Long shoot – shoot with long internodes, usually a main axis or extension shoot – Opposite: short shoot or spur shoot

Lophate pollen grain – the outer exine is raised in a pattern of ridges (lophae) surrounding depressions (lacunae)

Lorate – strap-shaped

Lysigenous aerenchyma – formed by cell differentiation and collapsing (lysis)

Lysigenous cavity – a space formed by the lysis of cells

Lozenge – diamond-shaped with rather elongated sides

Lozenge-aliform axial parenchyma – parenchyma cells surrounding or at one side of the vessel and with lateral extensions forming a diamond-shaped outline

Lumen (pl. lumina) – (of spore wall) the space bounded by reticulations; (of cell) the space within the walls

Lunate – half-moon shaped

Luniform (of a three-dimensional shape) – resembling a crescent moon

Lyrate, lyriform – lyre-shaped; pinnately lobed proximally yet with large rounded terminal lobe