Plant of the Week
Meadow pussytoes (Antennaria arcuata)
By Charmaine Delmatier (2016)
Meadow pussytoes (Antennaria arcuata) is a perennial whitish-woolly herbaceous forb usually associated with sub-irrigated meadows in semi-open wet depressions and drainages in sagebrush steppe and sagebrush grasslands. In Wyoming, it often occupies a very unlikely, uncommon habitat, within a specific vegetation zone; alkaline meadows with an unusual symmetric design of mounds and humps. It has been frequently speculated as to where the mounds and humps came from; and why do they seem to be similarly about 3-6 feet across and about 1-2 feet high. Adding to this mystery, it is dioecious; male flowers (staminate) on one plant and female flowers (pistillate) on another plant. It is able to reproduce vegetatively through its arching stolons or sexually by seed. A white woolly covering creates a thick indument on most of the plant and particularly on the arching stolons (arching stems spreading along the ground). The mounds are composed mostly of alluvial sands, with a certain amount of exposed soil, offering an opportunity for stolons to root. For all the above characteristics, meadow pussytoes is remarkably easy to distinguish from other all other Antennaria.
Meadow pussytoes (also known as ‘arching pussy-toes’) was first described in the early 1950’s by Art Cronquist from a J.H. Christ collection, dating back to 1946, from Blaine County, Idaho. Another location, collected in 1905 by F.W. Johnson in Fremont County, Wyoming, was later identified by Cronquist and generated the second known location. For a number of years these were the only two locations known; but now, with new information, we know it is distributed in three western states; Idaho, Nevada, and Wyoming. Elevation ranges from 4,500 to 7,500 feet.
The genus Antennaria is a member of the aster or sunflower family, Asteraceae, with 45 species distributed across the temperate and arctic/alpine regions of North America, Mexico, South America, and Eurasia. Thirty-four of those are represented in North America. The Sunflower family constitutes the largest plant family in the world with approximately 1,550 genera and 23,000 species. In North America, the numbers are considerably lower with 418 genera and 2,413 species. In comparison, the orchid (Orchidaceae) and legume (Fabaceae) families are second and third worldwide. With the multitude of species in Asteraceae, it is a kind relief to easily identify meadow pussytoes in the field.
A modest forb, its arching woolly stolons can extend up to four inches. The flowering stems have a wider range in height averaging 2-15 inches tall. The basal leaves are densely woolly and are broadened at the tip (obovate) with one to three dominant nerves. The stem leaves are linear and range from 5-40 mm long. Phyllary tips are whitish, and the flowers are no longer than 5 mm.
In 1990, Christine Lorain, with Idaho Game and Fish Department, reports the population is located between a thermal spring and cold water channel on semi-barren to moss-covered openings. The substrates vary from black clay soils to silt/loams. As with the Wyoming and Nevada populations, all sites are associated with a calcium carbonate component (lime soils) and most all populations have had some occasional hoof-treading from cattle grazing. It is an unusual relationship within this micro-niche between cattle and rare plant, but one that might solve our mystery of the mounds.