Montana Field Guide

Fendler Cat's-eye is an annual herb with simple or branched stems that are 5-20 cm high. The alternate, narrow, strap-shaped leaves may be up to 3 cm long; those at the base are usually brown by the time the plant is fruiting. The foliage is sparsely covered with spreading hairs. Tiny, white flowers are borne on coiled stalks that unwind and elongate as flowering progresses from the base upward. The corolla is ca. 1 mm high and has a small, united portion below and 5 spreading petals above. The calyx is covered with stiff, straight hairs and becomes 4-6 mm long in fruit. Within each fruiting calyx are 4 smooth, shiny, narrowly lance-shaped nutlets that are ca. 1.5 mm long and 1/3 as wide; 1 or more of these may be missing.

Flowering occurs from May to early July. Mature nutlets are necessary for positive identification.

Cryptantha fendleri is distinguished by the diffuse branching of its inflorescence and the nutlets, which are lance-shaped and 1/3 as wide as they are long (0.5-0.7 mm wide).

Cryptantha fendleri is widespread in the western U.S. However, in Montana this species is known only from two large sandhill areas at opposite corners of the state - the Centennial sandhills in Beaverhead County, and the Medicine Lake sandhills in Sheridan County. It grows in open areas of sand dunes, and occupies a range of sparsely vegetated sites and successional stages. In the sandhills of Sheridan County, it was found not only in blowouts, but throughout much of the gentler sandplains where grass cover is patchy. Associates there include Oryzopsis hymenoides, Psoralea lanceolata, Stipa comata, Sporobolus cryptandrus, and Cyperus schweinitzii. Associates in the Centennial sandhills include Allium textile, Elymus trachycaulus, Stipa comata, Eriogonum ovalifolium, Psoralea tenuiflora, Phacelia hastata, and Astragalus ceramicus.

Population sizes of this annual species can fluctuate widely from year to year, depending on conditions. The species is restricted to very sandy soils of early successional habitats, favoring the crests, upper slopes and blowouts of sandhills. Like many other rare plants of the sandhills, this species requires the open sand of early successional areas, and declines when plant succession leads to later stages in which vegetation fully colonizes areas of formerly open sand. These open habitats are maintained by a combination of wind, fire, and grazing by both livestock and small mammals (Lesica and Cooper 1998). Some level of disturbance can help maintain the early successional habitat required by this plant. At one locality, C. fendleri was found growing along livestock trails and old roads.

The removal of natural disturbance regimes, including fire, ungulate grazing and pocket gopher activity, can result in dune stabilization, reducing the extent of early seral blowout vegetation upon which this species depends. It would benefit from restoration of the fire regime and/or moderate grazing, at least in years following burns. Fendler cat's-eye does not grow among tall, dense grasses, and the practice of seeding sandhills areas to crested wheatgrass (Agrpopyron cristatum) has reduced available habitat. It has been found to persist under heavy grazing, and also grows where brittle pricklypear (Opuntia fragilis) is common and indicates past heavy grazing. Severe destabilization of the dunes, e.g., from off-road vehicle use, can also damage this species' habitat.

STATE THREAT SCORE REASON
Reported threats to Montana's populations of Fendler’s Cat’s-eye concern the disturbance regime necessary to sustain its habitat (MTNHP Threat Assessment 2021). Fendler’s Cat’s-eye establishes on sand dune blowouts resulting from frequent wind erosion. Occasional fire disturbance is likely to have an important role in preventing long-lived vegetation from establishing on dunes. Management actions that interrupt disturbance events such as dune stabilization and fire suppression threaten populations by degrading habitat quality, and eventually reducing the area of suitable habitat.