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San Elijo Lagoon Plant Guide Glossary

Find descriptions of terms or words found in within the plant guide.

Achene : A dry, one seeded fruit that does not open when ripe.

Angiosperm : Flowering plants; plants in which the ovules are produced and fertilized and develop within an ovary. Traditionally divided into two groups, dicots and monocots, recently taxonomists have separated a few small groups of more primitive (basal) dicots. The remaining dicots are now known as eudicots.

Anther : Upper portion of the stamen that produces the pollen. Image

Awn : A long, bristle-like appendage as on the floret of a grass. Image

Basal : Growing from or at the base of a plant; a basal rosette is a clump of leaves at the plant base.

Bract : A modified leaf sometimes associated with a flower; may resemble a small leaf, a petal or a scale.

Bulb : A swollen, underground stem, covered with leaves that are often papery and that serves as a storage organ. Casually used to include similar structures such as corms and rhizomes

Calyx : Outermost ring of flower parts, composed of sepals. Usually green. Encloses the developing bud and usually persists below the open flower. Image

Capsule : A dry fruit that splits open when ripe; it has many seeds in several chambers.

Catkin : A dense, cylindrical cluster of unisexual flowers, usually lacking petals.

Cauline : Growing from or on the stem of a plant.

Clone : Produced by vegetative reproduction.

Composite flower head : The specialized flower of the Sunflower family (Asteraceae). Tiny flowers, crowded together on a common base (the receptacle), resemble a single bloom. Flowers are of one or two types: symmetrical disk flowers and strap-shaped ray (or ligulate) flowers.    Image  

Compound leaf : A leaf composed of distinct, leaf-like leaflets arranged along the leaf stem. Arrangement either bilaterally symmetrical (pinnate) or radially symmetrical (palmate). A leaflet may be distinguished from a true leaf because a leaf has a small bud where the stem joins the main plant; a leaflet does not.

Cordate : Heart-shaped; a cordate leaf has a rounded-notched base and acute or pointed tip.

Corolla : Collective term for the petals on a flower. Image

Cotyledon : “Seed leaf”; leaf produced in the embryo and usually the first to emerge on a young plant. Traditionally, flowering plants were divided into Monocotyledons (monocots) and Dicotyledons (dicots) depending on whether the embryo had one or two cotyledons. Although this system of classification has been modified, the monocot group is unchanged.

Dicot : Or Dicotyledon; in a previous taxonomic system this was one of two major divisions of flowering plants, characterized in part by having two seed leaves (cotyledons) and flower parts usually in multiples of 4’s or 5’s. The dicots were recently replaced by eudicots and and small group of primitive species now called primitive (basal) dicots; the eudicots correspond closely with the original dicot division.

Dioecious : Having male and female reproductive organs in different flowers on different plants.

Disk floret : (Disk flower): A tiny, symmetrical flower of a composite flower head (sunflower family, Asteraceae). In a daisy, disk florets form the inner eye.    Image

Eudicot : or Eudicotyledon: the largest group of flowering plants.  Modern taxonomy has split the former Dicotyledon group into  eudicots (or “true dicots” ) and primitive (basal) dicots.

Filament : Thread-like part of the male reproductive structure that supports the anther. Image

Floret : One flower of a composite flower head (Asteraceae)  Image; or one flower and bract of a grass (Poaceae)  Image  

Flower head : In the sunflower family, one group of flowers clustered on a common base; often assumed to be one blossom.  Image  

Fruit : The structure around the seed or seeds; a mature (fertilized) ovary.

Glume : One of two scale-like bracts at the base of a grass spikelet; unlike most bracts, a glume does not subtend a flower.  Image  

Gymnosperm : Plants in which the ovules are produced and fertilized and develop unprotected by ovary or fruit. Best known Gymnosperms are the conifers such as pines, firs, spruces and hemlocks.

Halophyte : A plant than can grow in a salty environment. This is defined and evaluated in terms of salinity (NaCl), but most halophytes can tolerate either salinity or alkalinity (often a mixture of other salts deposited by fresh water).

Haploid/Diploid : haploid: having cells with only one set, or n, chromosomes; diploid: having cells with two sets, or 2n, chromosomes, usually one set from each parent. The alternation between diploid and haploid phases is the basis for sexual reproduction.

Hypanthium : A cup- to tubular-shaped modification of the receptacle, formed from the fusion of the lower portions of the sepals, petals and stamens. These latter structures appear to arise from the rim of the hypanthium.

Inferior ovary : An ovary that arises below the insertion point of the petals and sepals; sometimes resembles a swollen portion of the flower stalk.

Inflorescence : An entire cluster of flowers including their stems or system of stems.

Involucre : A group of bracts (phyllaries) that form a unit below a flower, flower cluster, flower head (composite flower) or fruit.  Image  

Lanceolate : A shape that is much longer than broad and widest near the base.

Lemma : he lower of two bracts at the base of a grass floret; the upper is the palea.  Image  

Monocot : Monocotyledon; one of the major divisions of flowering plants; characterized by having one seed leaf (cotyledon) and flower parts usually in multiples of three.

Monoecious : Having male and female reproductive organs in different flowers on the same plant.

Nectary : Nectar producing glands, often in the base of a flower. Image

Node : Place on the stem where a root, leaf or branch originates; joint.

Oblanceolate : A shape that is much longer than wide and broadest nearer the tip than the center.

Obovate : In two dimensions, shaped like an inverted egg – somewhat longer than wide and widest near the top. Obovoid: shaped like an inverted egg –  three dimensionally ovate.

Ovary : The swollen basal portion of the pistil that produces the seeds.  Most ovaries are one of two types, superior or inferior. Unless otherwise specified, an ovary is superior.

Ovate : In two dimensions, shaped like an egg with widest part near plant. Ovoid: shaped like an egg – three dimensionally ovate.

Palea  In the sunflower family (Asteraceae), a small bract at the base of a disk floret; in the grass family (Poaceae), the upper of two bracts at the base of a floret; the lower is the lemma  Image .

Palmate : A radial arrangement with elements radiating from a common point; arranged like fingers around a palm.

Pappus : A hairy or bristly modified calyx on the seeds of some composite flowers; often aids in seed dispersal.  Image

Pedicel : Stalk of an individual flower or fruit.

Peduncle : Stalk of a flower cluster or inflorescence.

Petal : One of several modified leaves that surround the reproductive structures of a flower; often brightly colored. Image

Petiole : Leaf stalk.

Phyllary : One of several bracts around the base of a composite flower head.  Image  

Pinnate : A bilateral arrangement with elements on both sides of a common axis; arranged like a feather.

Pistil : The female reproductive structure of a plant, usually consisting ovary, style and stigma.   Image

Pollinium : A packet of pollen grains transported as a unit.

Ray floret : (Ray flower): A tiny, strap-shaped flower of a composite flower head (sunflower family, Asteraceae). In a daisy, ray florets form the outer halo.  Image  

Receptacle : The part of the plant to which a flower is attached. Image

Rhizome : A horizontal, underground stem that produces roots and vertical shoots.

Sepal : Individual element of the calyx, which encloses the flower bud; usually leaf-like.  Image

Sessile :  Lacking a pedicel (flower stem) or lacking a petiole (leaf stem); attached directly to stem.

Stamen : The male reproductive structure of a flowering plant. Consists of a pollen-producing anther supported by the thread-like filament. Image

Stellate : Star-shaped; having several arms from a central point.

Stigma : Top portion of the pistil which captures the pollen.  Image

Stipule : One or two appendages at a leaf base; may appear as scales, spines, glands, etc.

Stolon : A horizontal, above-ground stem that can produce roots and vertical shoots.

Style : Narrow portion of the pistil that connects the stigma and the ovary. Image

Superior ovary : An ovary that arises above the insertion point of the petals and sepals.

Taproot : A root that is longer, stronger and more dominant than the other roots.

Trichome : A hair-like structure.

Umbel : A flower arrangement in which the pedicels of the flowers originate from a single point, much like the ribs of an umbrella.