Lepidium_draba Knowpia

Whitetop
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	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, also known as whitetop, hoary cress,^[1] or Thanet cress,^[2] is a rhizomatous perennial flowering plant in the family Brassicaceae. It is native to western Asia and southeastern Europe and has been widely introduced elsewhere.

Description edit

Whitetop

Whitetop is a perennial herb that reproduces by seeds and by horizontal creeping roots.^[3] 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.^[4] 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.^[5] 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. Typically, each flower has four petals.^[4]^[6]

Typically each flower has four petals

Uses edit

Hoary cress was traditionally used for medicinal purposes, including anti-inflammatory and antibacterial treatments.^[4]

Distribution edit

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.^[7]^[8] It has been suggested that native grasses from the Poa genera may be able to outcompete hoary cress in North America.^[9]

Distribution in United States edit

References edit

^ BSBI List 2007 (xls). Botanical Society of Britain and Ireland. Archived from the original (xls) on 2015-06-26. Retrieved 2014-10-17.
^ W Bond; G Davies; R Turner. "The biology and non-chemical control of Hoary Cress (Cardaria draba (L.) Desv.)" (PDF). Gardenorganic.org.uk. Retrieved 22 March 2022.
^ "Lepidium draba Profile – California Invasive Plant Council". Retrieved 2023-06-17.
^ ^a ^b ^c Scurfield, G. (July 1962). "Cardaria Draba (L.) Desv". The Journal of Ecology. 50 (2): 489–499. doi:10.2307/2257459. ISSN 0022-0477. JSTOR 2257459.
^ "Hoary cress (Cardaria draba)". agri.nv.gov. Retrieved 2023-06-17.
^ MULLIGAN, GERALD A.; FINDLAY, JUDY N. (January 1974). "The biology of canadian weeds. 3. cardaria draba, c. chalepensis, and c. pubescens". Canadian Journal of Plant Science. 54 (1): 149–160. doi:10.4141/cjps74-024. ISSN 0008-4220.
^ "Hoary Cress". Weed Identification & Information. Australian Weeds Committee. Archived from the original on 2015-04-14. Retrieved 2015-04-12.
^ "Weedy Connection: Hoary Cress". Retrieved 2023-06-14.
^ Puliafico, Kenneth P.; Schwarzländer, Mark; Price, William J.; Harmon, Bradley L.; Hinz, Hariet L. (March 2011). "Native and Exotic Grass Competition with Invasive Hoary Cress (Cardaria draba)". Invasive Plant Science and Management. 4 (1): 38–49. doi:10.1614/IPSM-D-10-00041.1. ISSN 1939-7291. S2CID 85677227.

External links edit

Species Profile - Whitetop (Lepidium draba), National Invasive Species Information Center, United States National Agricultural Library. Lists general information and resources for Whitetop.
Hoary cress - Lepidium draba, Invasive Plant Atlas of the United States,
Cardaria_spp, Bugwood Wiki - Invasive Pest Management