This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol3", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Annual glabrous or viscid-pubescent herbs, with alternate spinose-pinnatifid leaves, or the lowest entire, and numerous small flowers in dense terminal bracted clusters. Calyx prismatic or obpyramidal, the tube 5-angled, 5-cleft, not accrescent in fruit, not distended by nor ruptured by the ripening capsule, the sinuses scarious, the lobes mostly unequal, erect or spreading, spiny-tipped, entire, or often toothed. Corolla tubular-funnelform or salverform, 5-lobed, the lobes oval or oblong. Stamens straight or declined, equally inserted in or below the throat of the corolla. Ovary 2-3-celled; ovules solitary, few or several in each cavity. Capsule 1-3-celled, dehiscent or indehiscent. Seeds mostly mucilaginous and emitting spiral threads when wetted. [In honor of Navarrete, a Spanish physician.]
About 24 species, natives of western America. Besides the following, some 20 others occur in the western United States. Type species: Navarretia involucrata R. & P.
Depressed, tufted, somewhat pubescent; stem usually branched, 1' - 3' high. Leaves sessile, 1/2' - 1' long, 1 - 2-pinnatifid into almost filiform rigid acicular segments; flowers about 2" long, white, densely capitate; calyx-lobes awl-shaped, mostly toothed, about as long as the tube and equalling the corolla, the sinuses more or less white-pubescent; calyx-tube about equalling the indehiscent 1 - 6-seeded capsule.
In dry soil, Nebraska and South Dakota to Washington and Arizona. Summer.