Arizona Cottontop (Digitaria californica)

Main Sources: Gould, Frank, 1951, Grasses of the Southwestern United States, Tucson: University of Arizona Press; Shreve, Forrest & Ira Wiggins, 1964, Vegetation and Flora of the Sonoran Desert, Vol. 1, Palo Alto: Stanford University Press; Kearney, Thomas & Robert Peebles, et al, 1960, Arizona Flora, Berkeley: University of California Press; McClaran, Mitchel & Thomas Van Devender, 1995, The Desert Grassland, Tucson: University of Arizona Press; van Devender, Thomas & Mark Dimmitt, "Desert Grasses", in Phillips, Steven& Patricia Comus, eds., 2000, A Natural History of the Sonoran Desert, pp. 265-80, Arizona-Sonora Desert Museum Press, Tucson; Ruyle, George & Deborah Young, eds., 1997, Arizona Range Grasses, Tucson, University of Arizona College of Agriculture; U.S.D.A. Conservation Districts of Southeastern Arizona,, n.d., Grasses of Southeastern Arizona. Washington, D.C.

A green to bluish-green perennial bunchgrass, Arizona Cottontop may reach 4 feet in height. Its lower stems are firm and erect from a hard base, and typically remain green through the winter season. Spikelets are covered with silky hairs that give the seedhead its cottony appearance. The dense stand of it shown above is occuring on the edge of a watertank -- in most locations on our lands we see it much smaller and scattered, as below in the Notch Basin, in November:

A bunch of last year's inflorescences in the Notch Basin, May 2004:

In a richer summertime context, the ripening inflorescence looks like this: (Click on the image for a close-up)

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