sheath

leaf part

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Last updated

July 13, 2026

Quick Summary

The leaf sheath, also known as a leaf base, is the part of a leaf that typically broadens out to partially or fully enclose the stem. In some plants, like those in the Polygonaceae family, this sheath expands into a tubular structure called an ocrea. This part of the leaf plays a role in the overall structure and development of the plant.12

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palm
Leaves
Most have a sheath, petiole or leafstalk, and blade. Sheaths sometimes are elongate or tubular, and when they appear to form a continuation of the stem, they are referred to as a crownshaft. The petiole is discernible above the sheath as a supporting axis devoid of leaflets.
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Most have a sheath, petiole or leafstalk, and blade. Sheaths sometimes are elongate or tubular, and when they appear to form a continuation of the stem, they are referred to as a crownshaft. The petiole is discernible above the sheath as a supporting axis devoid of leaflets.
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Poaceae
Characteristic morphological features
…the leaves, particularly the leaf sheaths. Arising at nodes and encircling the internode above, sheaths counter the tendency for the internode to bend at the basal growing point, where it is weakest.
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…the leaves, particularly the leaf sheaths. Arising at nodes and encircling the internode above, sheaths counter the tendency for the internode to bend at the basal growing point, where it is weakest.
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Zingiberales
General features
…indicate the position of leaf sheaths already shed by the mature stems. The most common type of stem in Zingiberales is short and below ground. In many gingers, all leaves arise at ground level, their clasping sheaths and leaf bases hiding the stem. In the bananas, the vegetative stem is…
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…indicate the position of leaf sheaths already shed by the mature stems. The most common type of stem in Zingiberales is short and below ground. In many gingers, all leaves arise at ground level, their clasping sheaths and leaf bases hiding the stem. In the bananas, the vegetative stem is…
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