Glossary List - The William & Lynda Steere Herbarium

Displaying 376 - 425 out of 1575 Object(s)

Term	Definition
Cross-section	A cut at right angles to the axis of an organ. Same as transverse section.
Crown	The top of a tree; i.e., all but the trunk.
Crownshaft	A conspicuous cylinder formed by the tubular leaf sheaths of some palms; e.g., the royal palms (Roystonea spp., Arecaceae).
Cruciform (cruciate)	Cross-shaped, e.g., the petals of species of Brassicaceae are often arranged in a cross-like pattern.
Cryptogam	A plant that does not produce seed.
Cucullate	Hood-shaped.
Cucullate	Hood-shaped. From the Latin word cucullus which translates as hood.
Culm	The stem of a grass or sedge.
Cuneate (cuneiform)	Wedge-shaped; usually referring to the base of a two-dimensional organ (such as a leaf blade) of which the angle formed by the meeting of the margins is less than 90°.
Cupule	A cup-shaped structure that usually subtends a fruit; e.g., that of many species of Lauraceae and Rhabododendron amazonicum.
Curator	A scientist that takes care of specimens in a museum. In the case of botany, the museum is a collection of dried specimens and labels glued to special paper which are archived in special cabinets.
Curved appendages	Referring to an appendage, most often a vestigial stamen, that arises from a non-expanded part of the ligule and curves slightly inward.
Cushion plant	The growth form of a plant, often of high altitudes, in which numerous stems are congested together resulting in a low, pillow or cushion-like growth form.
Cuticle	A waxy layer of the leaf blade that covers the epidermal cells.
Cuticle	A waxy layer of the leaf blade that covers the epidermal cells. The cuticle is sometimes modified to forma papillae.
Cuticular ridge	A raised ridge that parallels or curves around the stomatal crypts.
Cuticular wax	Flakes found on the abaxial leaf blade surface that look like they could have been formed by shedding of the cuticle.
Cyathium (plural = cyathia)	An inflorescence consisting of several naked staminate flowers accompanied by usually one naked pistillate flower and subtended and mostly enclosed by a cup-shaped involucre, characteristic of Euphorbia (Euphorbiaceae).
Cylindrical fruit	A fruit that is much longer than it is broad.
Cylindrical fruit	A fruit that is much longer than it is broad.
Cyme	A determinate inflorescence in which growth of the central axis is terminated by a flower that opens first and each branch or pair of branches subtending this flower then is terminated by a single flower. This pattern, when repeated several times, often results in a somewhat flat-topped inflorescence.
Cypsela (plural = cypselae)	A dry, indehiscent fruit derived from an inferior, bicarpellate ovary; e.g., in Asteraceae. Similar to an achene, but derived from an inferior ovary and attached to the fruit wall throughout, i.e., not at a single place as in an achene.
Deciduous	A process in which certain structures of a plant, e.g., leaves, fall in response to enviromental changes.
Decusada, decusado	Se refiere a las hojas opuestas en un mismo plano y a la vez esas son alternas con el siguiente par opuesto.
Decussate	A type of leaf placement in which opposite leaves at a node are arranged at right angles to the pair below and above them.
Decussate leaves	Referring to opposite leaves arranged with each succeeding pair at right angles to the pairs below and above them.
Dehisce (dehiscent)	Splitting open at maturity, usually applied to a fruit that opens to release seeds but other structures, such as sporangia may also be called dehiscent.
Dehiscent fruit	Referring to fruits that open via an operculum (= lid like in a teapot) at maturity.
Deltate	Shaped like an equilateral triangle. Same as deltoid.
Dentate (diminutive = denticulate)	Toothed; having a margin with sharp teeth oriented at right angles to the central axis of the structure bearing them.
Determinate inflorescence	A type of inflorescence in which the terminal or central flower opens first; for example in cymes.
Diadelphous stamens	Stamens united into two, often unequal, sets; e.g., those of many Fabaceae, which have nine stamens in one set and one stamen in the other.
Dialisépalo	Se refiere al cáliz que posee los sépalos libres. Opuesto a gamosépalo
Diaspore	Referring to the dispersal unit of a plant (e.g., the inflorescence, part of an inflorescence, the fruit, part of a fruit, or a seed).
Dichasial cyme	A determinate inflorescence in which growth of the central axis is terminated by a flower that opens first and each pair of branches subtending this flower then is terminated by a single flower.
Dichogamy (dichogamous)	Referring to a flower in which pollen is released and stigmas are receptive at different times.
Dichotomous growth	In morphology, a axis that successively forks into two more or less equal parts.
Dichotomous key	A dichotomous key aids in the identification of a family, genus, or species by progressively giving choices based on different states of a character (e.g., leaf complexity with the character states being leaves simple or leaves compound). A series of similar questions eventually leads to a possible identification of the plant in hand but this should be confirmed by reading descriptions, comparing with collections in a herbarium, or with images from various sources (e.g., Google images). If a monograph or flora exists for the group it is identified as they can be consulted to confirm the determination.
Dicliny (diclinous)	Referring to species with separate staminate and pistillate flowers. Dioecious and monoecious plants are examples of diclinous plants. Compare with monocliny.
Dicotyledon (dicot)	One of the two main groups of angiosperms usually characterized by having two cotyledons, net-veined leaves, and flower parts generally in fours or fives. In the classification of Cronquist (1981), this class is called Magnoliopsida. Dicotyledons are not monophyletic in the classfication system of the APG.
Didynamous stamens	With two pairs of stamens of unequal length.
Differentiated anthers	Referring to anthers that bear two types of pollen: 1) fertile pollen that is transferred to other flowers to effect fertilization and 2) sterile (= fodder) pollen that serves as a pollinator reward. The two types of pollen may differ in their ability to germinate, in their color (fodder pollen is often yellow), and in their morphology (e.g., the fertile anthers of Couroupita guianensis are in monads and the sterile ones are in tetrads), and their location (e. g., the fertile anthers are near the stigma and the sterile ones are in a group separate from the stigma in many species of Swartzia.
Diffuse roots	A root system that consists of many more-or-less branches of equal sizes, i.e., there is no taproot.
Digging tools	Tools used to dig up the underground parts of plants. These kinds of tools, which can be purchased in hardware stores anywhere, come in all shapes and forms but we prefer the dandelion digger shown in the upper part of this image. For more information about plant collecting see Tropical Plant Collecting: From the Filed to the Internet. This book can be purchased at: http://tecceditora.com/ or Amazon.com.
Digitate	Arranged as fingers on a hand; in the Cyperaceae and Poaceae, referring to such an arrangement of spicate branches of an inflorescence; for application to leaves, see palmate.
Dilated	Spread out or expanded, e.g., the base of a filament in relation to the more constricted apex.
Dimorphic	Occurring in two forms; e.g., in the Mimosaceae, different flower shapes in the same inflorescence. Compare with heteromorphic and monomorphic.
Dioecy (dioecious)	Describing a sexual condition of a species that bears only functionally staminate flowers on some plants and only functionally pistillate flowers on other plants. Compare with monoecious.
Diplochory	Seed dispersal in two different ways, e.g., a seed is eaten by a monkey and then is moved further by ants carrying it away from the monkey's dung.
Diploid	Having two sets of chromosomes; e.g., a plant with a diploid chromosome number of 2n = 24 has two sets of 12 each (one from the paternal and the other from the maternal parent).