Angiosperms (Flowering Plants) • Earth.com

Whitetop

(Lepidium draba)

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Description

Lepidium draba, the whitetop or hoary cress, or Thanet cress, is a rhizomatous perennial flowering plant in the family Brassicaceae. It is native to western Asia and southeastern Europe and widely introduced elsewhere. Whitetop is a perennial herb that reproduces by seeds and by horizontal creeping roots. The stem is stoutish, erect or spreading, 10 to 80 cm tall, branched, covered sparsely with ash-colored soft hairs to heavily covered. The leaves are alternating, simple, and mostly toothed. The basal leaves are 4 to 10 cm, have a slight stem (petiole), and are long and flat, lance-shaped to egg-shaped, with the narrow end attached to the stalk. On the upper part of the stem the leaves are attached directly to the stalk (sessile), are 2 to 6.5 cm long, and are oblong or tapering the point, with broad bases that clasp the stalk. Whitetop has slightly domed flower clusters in which the individual flower stalks grow upward from various points off the branch to approximately the same height (corymb-like). The petals are white, clawed, and 3 to 5 mm long, about twice the length of the sepals. It is native to western Asia and southeastern Europe and is an invasive species in North America, introduced by contaminated seeds in the early 1900s. Also known as Cardaria draba, hoary cress is a weed in much of south-east and south-west Australia as well. Lepidium is a genus of plants in the mustard/cabbage family, Brassicaceae. The genus is widely distributed in the Americas, Africa, Asia, Europe, and Australia. It includes familiar species such as garden cress, maca, and dittander. General common names include peppercress, peppergrass, pepperweed, and pepperwort. Some species form tumbleweeds. The genus name Lepidium is a Greek word meaning 'small scale', which is thought to be derived from a folk medicine usage of the plant to treat leprosy, which cause small scales on the skin. Another meaning is related to the small scale-like fruit. There are about 175 to 220 species in the genus. 10 species are found in California.

Taxonomic tree:

Domain:
Kingdom: Plantae
Phylum: Magnoliophyta
Class: Magnoliopsida
Order:Brassicales
Family:Brassicaceae
Genus:Lepidium
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