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H

Habit: The general appearance, characteristic form, or mode of growth of a plant.

Half-inferior: [Ovaries] {position} With the lower portion of the ovary enclosed by and fused to a floral cup, the whorl of sepals and petals (perianth) and/or stamens (androecium) thus appearing to arise from near the middle of the ovary.

Halophyte: a plant that grows naturally in soils having a high content of various salts, that usu. resembles a true xerophyte and that occurs in many families (as Chenopodiaceae, Compositae, Plumbaginaceae)

Hastate: [Leaf bases, Leaflet bases, Leaflets, Leaves] {shape} Arrowhead-shaped, but with the basal lobes turned outward rather than downward.

Head: [Inflorescences] {type} An inflorescence with crowded, sessile or nearly sessile, small flowers (florets) borne on a common receptacle which is convex or flat and often disc-shaped; characteristic of the family Asteraceae.

Helicoid cyme: [Inflorescences] {type} A cyme in which the lateral branches develop on only one side, all segments branching on the same side, causing the inflorescence to curve or coil.

Helophyte: a perennial marsh plant having its overwintering buds under water

Hemi-parasitic: [Plants] {nutrition} Partially parasitic; in plants, photosynthetic but deriving at least some nutrients from a host organism.

Herbaceous: [Plants] {woodiness} Having little or no living portion of the shoot persisting aboveground from one growing season to the next, the aboveground portion being composed of relatively soft, non-woody tissue.

Hesperidium: [Fruits] {type} A specialized berry with a leathery skin or rind, and a fleshy interior divided into sections or locules, as lemons and oranges (Citrus).

Heterosporous: characterized by the production of asexual spores of more than one kind

Hip: [Fruits] {type} An aggregation of achenes surrounded by an urn-shaped, more or less fleshy floral cup or hypanthium, as in roses (Rosa).

Hirsute: [Buds, Leaf lower surface, Leaf upper surface, Petioles, Phyllaries, Rachises, Sepals, Young twigs] {pubescence type} With coarse, stiff hairs.

Hispid: [Buds, Leaf lower surface, Leaf upper surface, Phyllaries, Sepals, Young twigs] {pubescence type} With stiff, bristly, usually stout-based hairs.

Hollow: [Pith] {type} With an uninterrupted central cavity, the pith lacking or disintegrating prior to maturity.

Homosporous: characterized by the production by various plants (as the club mosses and horsetails) of asexual spores of only one kind

Hoods: Erect columnar structures on the upper part of a Milkweed flower in the Asclepiadaceae.

Horn: A slender horn-like structure inside or adjacent to the hood of a Milkweed flower in the Asclepiadaceae. The horns are straight or curved, and usually shorter than the hoods. The flowers of some Milkweed species lack horns.

Host: a living animal or plant affording subsistence or lodgment to a parasite

Husk: the outer covering of a kernel or seed esp. when dry and membranous

Hydrophyte: a vascular plant growing wholly or partly in water; esp : a perennial aquatic plant having its overwintering buds under water b : a plant requiring an abundance of water for growth and growing in water or in soil too waterlogged for most other plants to survive -- compare mesophyte, xerophyte

Hygroscopic: sensitive to moisture b: induced by moisture

Hypanthium: an enlargement of the usu. cup-shaped receptacle bearing on its rim the stamens, perals, and sepals of a flower and often enlarging and surrounding the fruits (as in the rose hip)

Hypanthium: A cup or tube usually formed by the fusion of the basal parts of the sepals, petals and/or stamens, and on which they are seemingly borne; surrounds the ovary, or ovaries, and may be fused wholly, partly or not at all to them; the shape varies from disc-like to cup shaped, flask-like or tubular; a floral cup.

Hypogynous: [Flowers] {perianth position} With the perianth (the whorl of sepals and petals) not fused into a floral cup of any kind and arising at the same level as the base of the ovary.

I

Imbricate: (1) [Leaves] {habit} Overlapping, as the shingles on a roof.

Imbricate: (2) [Bud scales] {type} Overlapping, as the shingles on a roof.

Impressed: [Leaf upper surface venation] {relief}

Incised: [Leaf margins, Leaflet margins, Petal margins, Phyllary margins, Sepal margins] {form} Margins sharply and deeply cut, usually jaggedly.

Inconspicuous: [Stipule scars] {presence} Not readily visible.

Indehiscent: Not splitting or forming an opening at maturity, the contents being released for dispersal only after decay, digestion or erosion of the structure, as certain fruits, such as achenes and berries, that retain their seeds when ripe. (

Indeterminate inflorescence: An inflorescence in which the lowermost or outermost flower opens first, with the main axis often elongating as the flowers develop, as in racemes.

Indusium: The sorus (or spore-bearing structure) of some ferns is partially covered by a pale membrane that is called an 'indusium.' The indusium may fade away as the fertile leaf of a fern matures. The plural form of this term is 'indusia.'

Inferior: [Ovaries] {position} With the ovary wholly enclosed by and fused to a floral cup, the whorl of sepals and petals (perianth) and/or stamens (androecium) thus appearing to arise from the top of the ovary.

Inflorescence: 1) The mode or pattern of flower bearing; the arrangement of flowers on the floral axis. 2) A basic unit of the flower-producing portion of a plant, composed of one or more flowers and any supporting stalks and appendages (e.g. bracts, involucres, etc.); a flower cluster.

Infrapetiolar: [Buds] {position} Axillary and surrounded by the base of the leaf stalk or petiole.

Insertion: The location of points of attachment of a structure (e.g., a leaf) to some dissimilar bearing structure.

Internode: The portion of a stem between two nodes, i.e. the part where leaves and/or branches do not arise.

Involucre: A whorl of bracts subtending a flower or flower cluster.

Involute: [Leaf margins, Leaflet margins] {vertical disposition} With margins rolled inward, toward the upper side. (Compare with plane and revolute.)

Irregular: of a flower or its parts : lacking uniformity; specif : zygomorphic (or) bilaterally symmetrical; said of a flower in which all parts are not similar in size and arrangement on the receptacle (compare regular, and see zygomorphic) (h)

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K

Keel: A longitudinal ridge, more or less triangular in cross section, like the keel of a boat.

Keeled: (2) [Apophyses] {keels} With a vertical ridge or keel.

Keeled above: [Leaves] {keels} With a longitudinal ridge or keel, more or less triangular in cross section, running down the center of the upper surface of the leaf.

Keeled below: [Leaves] {keels} With a longitudinal ridge or keel, more or less triangular in cross section, running down the center of the lower surface of the leaf.

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L

Lacerate: [Leaf margins, Leaflet margins, Petal margins, Phyllary margins, Sepal margins] {form} Margins irregularly cut, appearing torn.

Laciniate: [Leaf margins, Leaflet margins, Petal margins, Phyllary margins, Sepal margins] {form} Cut into narrow, ribbon-like segments.

Lance-cylindric: [Buds] {shape}; [Seed cones] {shape before opening, shape when open} Intermediate in shape between lanceoloid and cylindric.

Lance-obovoid: [Seed cones] {shape before opening, shape when open} Intermediate in shape between lanceoloid and obovoid.

Lanceolate: [Leaflets, Leaves, Petals, Phyllaries, Sepals] {shape} Several times longer than broad, widest near the base and tapering to a point at the apex; lance-head-shaped.


Lanceoloid: [Buds] {shape}; [Seed cones] {shape before opening, shape when open} Considerably longer than broad, rounded or somewhat flattened in cross section, broadest near the base and somewhat concavely tapering toward the tip; lance-head shaped in outline.

Lance-ovoid: [Buds] {shape}; [Seed cones] {shape before opening, shape when open} Intermediate in shape between lanceoloid and ovoid.

Latex: a milky usu. white fluid of variable compostition that is usu. made up of various gum resins, fats, or waxes and often a complex mixture of other substances frequently including poisonous compounds, this is found in or produced by cells of plants especially of the Asclepiadaceae but also of the Apocynaceae, Sapotaceae, Euphorbiaceae, Moraceae, Papaveraceaea, , and Compositae.

Leaf: A lateral outgrowth of a stem, usually green and photosynthetic, and often consisting of a stalk (petiole) and an expanded portion (blade); leaves may also be needle-like or scale-like in form.

Leaf complexity: The division (or not) of a leaf into distinctly separate segments or leaflets; whether a leaf is simple or compound.

Leaf insertion: The position of leaves as defined by the relative location of their points of attachment on the stem (e.g. alternate, opposite, whorled, etc.).

Leaf scar: The scar remaining on a twig at the former place of attachment of a leaf, after the leaf has fallen.

Leaf venation: The visible pattern of veins on a leaf.

Leaflet: One of the separate, leaf-like segments of a compound leaf.

Leathery: [Seed cone scales] {type} Moderately thick, tough and pliable.

Legume: [Fruits] {type} A usually dry fruit that splits open (dehisces) lengthwise along two sutures and has a single interior chamber (locule), as in the pea family (Fabaceae).

Lemma: A lemma is one of the floral scales in a spikelet of grass; the lemmas are located above the glumes. Lemmas usually occur in pairs in each spikelet, although sometimes they occur individually. Typically, one lemma in a pair is fertile and contains a floret, while the other lemma is sterile. The lemmas provide some protection for the reproductive organs of the florets and its developing seed (or grain). Like the glumes, the lemmas are often keeled and somewhat flattened. The fertile and infertile lemmas can appear nearly identical to each other, or their appearance may be somewhat different from each other. Sometimes the tips of the lemmas are awned.

Lenticel: The specialized openings in the bark of some woody stems that provide a passage for gas exchange, often appearing as small, circular to elongate marks on the surface of the bark.

Lepidote: Covered with small scales.

Ligule: A structure on the inner side of a leaf at the junction of the sheath and blade. This structure consists of thickened tissue that may contain papery membranes or a row of hairs. The characteristics of a ligule are more observable when the blade of a leaf is pulled away from the culm. Sometimes the ligule is used in the identification of grasses and sedges.

Linear: [Leaflets, Leaves, Petals, Phyllaries, Sepals] {shape} Long and narrow, with the sides more or less straight and parallel. (Compare with acicular, ensiform, filiform and lorate.)

Lobe: A more or less major protrusion or segment of a leaf or leaflet delimited by concavities (sinuses) in the leaf margin.

Locule: A distinct compartment or cavity within organs such as ovaries, anthers or fruits.

Loculicidal capsule: [Fruits] {type} A capsule that splits open (dehisces) lengthwise directly into the locules or chambers of the ovary, more or less midway between the ovary partitions.

Loment: [Fruits] {type} A usually dry fruit that breaks apart crosswise at points of constriction into one-seeded segments, as in beggars ticks (Desmodium); considered to be a modified legume.

Lorate: [Leaflets, Leaves, Petals, Phyllaries, Sepals] {shape} Long and moderately narrow, flat in cross section, with sides more or less straight and parallel, often flexible and curving; strapshaped.

Lyrate: [Leaflets, Leaves] {shape} Pinnately lobed, with a large, rounded terminal lobe and smaller lower lobes; lyre-shaped.

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M

Marbled [Leaf lower surface, Leaf upper surface] {color variegation} A surface traversed by irregular veins of color, as a block of marble.

Margin: The edge, as in the edge of a leaf blade.

Marginal: [Placentation] {type} Attachment of ovules along one side of a simple ovary.

Mericarp: [Fruits] {type} One of the segments of a schizocarp once it has split apart, often appearing to be a separate fruit; usually one-seeded and not splitting open at maturity (indehiscent); as the small, relatively hard-coated nutlets in the mint familiy (Lamiaceae) or the individual winged samaras of maples (Acer).

Mesic : of a habitat : having or characterized by a moderate amount of moisture : neither hydric not xeric; of a plant or flora : mesophytic

Midrib: A main or primary vein running lengthwise down the center of a leaf or leaf-like structure; a continuation of the leaf stalk (petiole); the midvein.

Midvein: A main or primary vein running lengthwise down the center of a leaf or leaf-like structure; a continuation of the leaf stalk (petiole); the midrib.

Moderately lobed: [Leaflets, Leaves, Petals, Sepals] {lobing} With lobes that are cut approximately < to = the distance to the midrib or base.

Monadelphous: united by the filaments into one group usu. forming a tube around the gynoecium

Monocarpic: bearing fruit but once and dying--used esp. of annual and biennial flowering plants; compare century plant

Monocarpous: having a single ovary

Monoclinous: having the stamens and pistils in the same flower

Monoecious: Plant species that produce both male and female flowers, but not perfect flowers, on the same plant. An example of a monoecious species is Xanthium strumarium (Common Cocklebur).

Monophyletic: developed from a single common parent form

Monopodial: having or involving offshoots from a main axis

Motile: exhibing or capable of movement

Mucronate: [Leaf apices, Leaflet apices, Petal apices, Phyllary apices, Sepal apices] {shape} Ending abruptly in a short, hard point. (Compare with apiculate, aristate and caudate.)

Multilocular: With more than one interior compartment or locule.

Multiple fruit: [Fruits] {type} A fruit formed from several flowers (and associated parts) more or less coalesced into a single structure with a common axis, as a mulberry (Morus) or pineapple (Ananas comosus).

Mycorrhiza: the symbiotic association of the mycelium of a fungus (as various basidiomycetes and ascomycetes) with the roots of a seed plant (as various conifers, beeches, heaths, and orchids) in which the hyphae form an interwoven mass investing the root tips or penetrate the parenchyma of the root

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