Lepidium draba

Whitetop
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Rosids
Order: Brassicales
Family: Brassicaceae
Genus: Lepidium
Species: L. draba
Binomial name
Lepidium draba
L.
Subspecies
  • Lepidium draba subsp. draba (= Cardaria draba)
  • Lepidium draba subsp. chalepense (L.) P.Fourn. (=Cardaria chalepensis)
Synonyms

Cardaria draba (L.) Desv.

Lepidium draba (whitetop or hoary cress[1]) is native to western Asia and eastern 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.[2]

Whitetop

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.

Distribution in United States

References

  1. "BSBI List 2007". Botanical Society of Britain and Ireland. Archived from the original (xls) on 2015-02-25. Retrieved 2014-10-17.
  2. "Hoary Cress". Weed Identification & Information. Australian Weeds Committee. Retrieved 2015-04-12.

External links

Other reading

Agriculture Research Service (1970) "Cardaria draba (L.) Deav." Selected Weeds of the United States Agriculture Research Service United States Department of Agriculture, Washington, DC, p. 200

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