Imbricate.   Having margins overlapping


Imparipinnate.   Pinnate with a conform terminal leaflet. Imparipinnately Compound - Odd-pinnately compound, with a terminal leaflet


Imperfect or Unisexual.   With stamens or carpels absent in the flower


Implicate.   With both lamina margins folded sharply inward


Incised.   Margins sharply and deeply cut, usually jaggedly


Inclinate.   With lamina folded or curved transversely near the apex


Inclined.   Ascending at 46-75° angle of divergence


Included Veinlets.   Veins ending inside areoles


Incomplete.   Leaf without one or more parts: blade, petiole, stipules; one or more types of floral parts absent


Incrassate.   Thickened


Incumbent or Notorhizal.   Reclinate with sides of cotyledons against hypocotyl


Incurved.   Curved inward or upward


Indehiscent Capsule.   One that does not dehisce at maturity, as in Peplis


Indeterminate or Evergrowing.   Continual growth of plant parts, not limited by a cessation of meristematic activity


Induplicate.   Having margins bent inward and touching margin of each adjacent structure


Indurate.   Hardened


Indusium.   A flap of tissue covering a sorus


Inequilateral.   With unequal sides


Inermous.   Unarmed, without prickles or spines


Inferior.   Other floral organs attached above ovary with hypanthium adnate to ovary


Inflated.   Swollen or thickened, as in Eichhornia


Inflexed.   Bent abruptly inward or upward


Infrafoliar.   On the stem below the leaves, as in the Arecaceae


Infrapetiolar or Subpetiolar.   Axillary bud surrounded by base of petiole


Infundibular.   Funnel-shaped


Integuments.   Outer covering of ovule; embryonic seed coat


Intercalary.   Growth region near the base of an internode or base of blade


Interfoliar.   On the stem between the leaves, as in the Arecaceae


Intermittent.   A renewal and cessation of meristematic activity which produces clusters of stems and/or leaves along an axis


Internode.   A section or region of stem between nodes


Interpetiolar.   With connate stipules from two opposite leaves


Interrupted or Discontinuous.   Symmetry of arrangement broken, with uneven lengths of internodes


Interstitial.   Growth all-over in an organ, no localized meristems, as in some fruits


Investing.   Axial embryo usually erect with thick cotyledons overlapping and encasing the somewhat dwarfed hypocotyl; endosperm wanting or limited


Involucel.   Small involucre; secondary involucre


Involucre.   A group or cluster of bracts subtending an inflorescence


Involute.   Margins or outer portion of sides rolled inward over upper or ventral surface


Irregular.   With floral parts within a whorl dissimilar in shape and/ or size


Isocotylous.   With cotyledons of same size and shape


Isodynamous.   With equally developed structures


Isomerous.   With same number of members in different whorls


Isopetalous.   With petals of same size and shape


Isophyllous.   With leaves of same size and shape


Isosepalous.   With sepals of same size and shape


Isostichous.   With equal rows


Jointed.   With stems that can be pulled apart easily at the nodes, as in Equisetum


Keel.   The two united petals of a papilionaceous flower; any structure ridged like the bottom of a boat


Lacerate.   Margins irregularly cut, appearing torn


Laciniate.   Cut into closely parallel ribbonlike or straplike projections


Lacuna.   Chamber or internal air space


Lamina.   The leaf tissue other than the veins or axes


Laminar.   Leaf-like stamen without a distinct anther and filament but with embedded or superficial microsporangia, as in Degeneria


Laminate.   With the placenta over the inner surface of the ovary wall


Lammas Shoots.   Abnormal late season shoots that develop from the terminal bud, not a recurring phenomenon as in flushing shoots


Lanate.   Covered with long, intertwined trichomes, cottony


Lanceolate.   Lance shaped, much longer than wide; widened at or above the base and tapering to the apex


Lanuginose.   Cottony, similar to lanate but trichomes shorter


Lateral or Axillary.   On the side of a structure or at the nodes of the axis. Lateral Embryo - Basal or baso-lateral embryo, discoid or lenticular, usually surrounded by copious endosperm. Lateral Leaf - Leaf on the side of the stem, as in heterophyllous species of Selaginella


Laterospermous.   On the side of the seed


Latiflorous.   With broad-flowers


Leaf.   A photosynthetic and transpiring organ, usually developed from leaf primordium in the bud; an expanded, usually green, organ borne on the stem of a plant. Leaf Primordium - Meristematic tissue that gives rise to a leaf. Leaf Scar - A mark indicating former place of attachment of petiole or leaf base. Linear Leaf - Narrow, flattened, triangular, or quadrangular leaf usually 1/2-2 in. long; e.g., Taxus, Picea


Leaflet.   A distinct and separate segment of a leaf


Leaf-opposed.   On stem opposite the base of the leaf, as in Alchemilla


Legume.   A usually dry, dehiscent fruit derived from one carpel that splits along two sutures


Lemma.   Outer scale subtending grass floret


Lenticel.   A pore in the bark


Lenticular.   Biconvex, usually elongate and flattish


Lepidote or Squamulose.   Covered with minute scales


Leptophyllous.   With leaves to 25 sq. mm in size.


Leptosporangiate.   Having the entire sporangium develop from a periclinal division of a superficial cell or small group of cells


Ligneous.   Woody


Ligulate or Ray.   Strap-shaped


Ligule.   An outgrowth or projection from the top of the sheath, as in the Poaceae; the strap-shaped portion of a ray or ligulate corolla; a small membranous outgrowth or projection at the base of the leaf, appearing above the sporangium in fertile leaves, as in Selaginella and Isoetes


Limb.   Expanded portion of corolla or calyx above the tube, throat or claw


Lineate.   In lines, stigmatic surface linear


Lingulate.   Tongue-shaped, plano-convex in cross section


Lip or Labellum.   Either of two variously shaped parts into which a corolla or calyx is divided, usually into an upper and lower lip, as in the Lamiaceae and Orchidaceae. Lip Cells - The line of cells between which the sporangium dehisces


Lobate.   Lobe rounded; sinus depth variable; outer and inner margins concave


Lobe.   Any, usually rounded, segment or part of the perianth


Lobed.   Divided into lobes


Locule.   Compartment of an anther; ovary cavity


Capsule.  Loculicidal Capsule One that dehisces longitudinally into the cavity of the locule, as in Epilobium


Lodicule.   Abortive perianth part in the Poaceae; hyaline scales at base of ovary in the Poaceae


Loment.   A legume that separates transversely between seed sections


Long Shoot.   Elongated internodes, rapid annual growth. Long Bud Shoots - Abnormal buds or shoots which elongate, then have arrested growth without the development of leaves and lateral branches


Longitudinal.   Dehiscing along long axis of theca


Loose, Distant, or Scattered.   Parts widely separated from one another, usually irregularly


Lorate.   With elongate vertical waves in the margins or sides at right angles to the longitudinal axis


Lunate.   Crescent-shaped, with acute ends


Lyrate.   Lyre-shaped; pinnatifid with large terminal lobe and smaller lower lobes