Report on 1997 and 1998 Surveys for Astragalus geyeri var. triquetrus in Lake Mead NRA

Powell, Elizabeth

The spring of 1997 was a poor year for Astragalus geyeri var. triquetrus, threecorner milkvetch (Figure 1), in Lake Mead National Recreation Area (LMNRA) . Six areas in which the plant had previously been found in LMNRA and 2 areas outside the park were searched for plants in April, 1997. The species was found only at Sandy Cove on unconsolidated dunes above the beach. Eighty-three very small individuals that had produced very few flowers and pods were found It is estimated that the population in the area may have been about 100 plants. Because these plants had apparently flowered early and were dead by the time they were located, no research could be initiated. In 1998, plants were searched for in March and April on sandy habitats. Research was initiated on Sandy Cove where 131 plants were found (See Phenology of Threecorner Milkvetch, Astragalus geyeri var. triquetrus at Sandy Cove, Lake Mead National Recreation Area, NPS unpublished report.) (Figure 2). Four plants were found near Middle Point and about 12 plants were found at Ebony Cove (Figure 3).