Stipule

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stipule

[′stip·yül]
(botany)
Either of a pair of appendages that are often present at the base of the petiole of a leaf.

Stipule

 

either of a pair of lateral appendages at the base of a leaf. The stipules infrequently fuse with the leaf stalk and with each other. Many plants lack stipules. At the base of the leaf stalks of compound leaves there are analogous formations called stipels (for example, in beans). Stipules are generally small, but they are large in vetchling, peas, and violets. In some plants, such as bedstraw and Asperula, they resemble leaves; in others, such as the locust, they do not. Stipules often play a protective role. By fusing together and embracing the stem, they form a funnellike opening (in buckwheat and sorrel) that protects young leaves. In the buds of many plants the stipules partially cover the young leaves (oak, linden, elm) and fall after the leaf unfolds.

References in periodicals archive ?
nervosa, because both have large leaflets, but can be differentiated by the presence of persistent stipules and a calyx with relatively large internal sepals of (7-)10-14 x (4-)6-8 mm (vs.
Stipules persistent, linear, apex acute, base truncate, strigulose, margin ciliated, 5.
cana, with which it shares characteristics such as shape of the stipules and extrafloral nectaries located on the pedicels.
5 mm in diameter at or slightly below apex; stipules 2.
Bunchosia soejartoi is also distinguished by its rounded, often retuse leaf apices, few leaf glands, often sinuous abaxial leaf hairs, and stipules borne well above the base of the petiole.
Heteropterys tiinae differs from all other species of Heteropterys by the combination of small glabrous laminas bearing large glands abaxially, epipetiolar stipules, and umbels or corymbs of 4-6 flowers with small greenish petals borne on well-developed peduncles.
5 cm long, inevidently stigulose both surfaces, pale below; stipules semipersistent.
According Thomas (1991) the colleters are exclusively found on the adaxial side of the organs and their presence in stipules is quite common.
In this species, protection is reinforced by the sheath formed by the stipule pairs.
Key words: "Cerrado" vegetation, colleter, secretion, stipule, ultrastructure.
1 Stipules deeply bifid, divided more than half way, often nearly to the base; fruits dimidiate and deeply bisulcate (rarely only one seed developing and fruit thus appearing subglobose) .
Examination of the type collection clearly shows the entire to shortly bifid stipules (divided less than halfway) and globose (non-dimidiate) fruits, characters that differentiate this species from all other members of the genus.