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ECOLOGY ▪ EDUCATION ▪ ADVOCACY

Indiana Nature Biology Glossary

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BIB

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Samara: A winged, indehiscent fruit characteristic of maples (Acer spp.), ash (Fraxinus spp.), and other trees that contains one seed, also called “key.”


Samara

Scape: A leafless peduncle that originates from the base of a plant.


Scape

Sepal: A modified leaf that forms one of the individual sections of the calyx.


Sepal

Sessile: An adjective describing a part of a plant (typically a leaf or leaflet) that is attached directly at the base and lacks a stalk or a petiole.


Sessile Leaf

Sexual Dimorphism: Outwardly different physical characteristics between males and females of a given species, aside from their reproductive organs. Those species that exhibit sexual dimorphism are said to be “sexually dimorphic.”


Sexual Dimorphism Image
Sexually Dimorphic Golden-backed Snipe Flies (Chrysopilus thoracicus). Larger female on top, and smaller male on bottom.


Simple Leaf: A single, undivided leaf. The opposite of a simple leaf is a compound leaf.


Spadix: A type of inflorescence consisting of a fleshy spike containing many small flowers. Spadix-style inflorescences, usually surrounded by a spathe, are a characteristic of the arum family (Araceae).


Spadix

Spathe: A large bract or bracts that surrounds an inflorescence.


Spadix

Stamen: The male (pollen-producing) organ of a flower comprised of a filament and anther.


Stamen

Stratification: The requirement of an extended period of cold for seeds to break dormancy resulting in germination. Stratification is a process that occurs naturally through the colder period of winter, but it is often stimulated by horticulturists through refrigeration and other means.


Style: The usually elongated structure of the pistil that connects the stigma to the ovary.


Style

Subterminal (ST) Line: In Lepidoptera, the second most posterior wing line located between the post medial and terminal lines.

illustration of subterminal line

Subterminal line on large lace-border moth (Scopula limboundata)