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Northern Prairie Wildlife Research Center

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Aquatic and Wetland Vascular Plants of the Northern Great Plains

Pilea Lindl. -- Clearweed

Monoecious or dioecious, glabrous annuals; stems erect to decumbent, simple or branched, rather brittle and watery, translucent; cystoliths appearing as numerous minute, whitish or dark lines on the foliage of dried specimens. Leaves simple, opposite; blades thin and translucent, ovate, with 3 major veins arising from the base, broadly cuneate to rounded at the base, serrate, the teeth prominent, obtuse to rounded, the terminal tooth short to elongate; petioles subtending the inconspicuous, connate, membranous stipules. Flowers greenish, clustered in axillary cymes; male flowers with 4 sepals and 4 stamens; female flowers with 3 sepals, these often unequal; staminodes minute and scalelike; ovary superior, stigma sessile. Fruit a flattened, ovate achene, subtended by the persistent calyx.

Fernald, M. L.  1938.  Pilea in eastern North America.  Rhodora 38:169-170.

Lead Characteristic Go To
1 Achenes dark olivaceous to nearly black with a narrow pale margin. P. fontana
1 Achenes green, often marked with purple. P. pumila

10. Urticaceae, the Nettle Family
1. Pilea Lindl. -- Clearweed
1. Pilea fontana (Lunell) Rydb.
2. Pilea pumila (L.) A. Gray

Return to Family -- Urticaceae - The Nettle Family
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