|Listed||June 22, 1992|
|Description||Silky, creeping perennial herb with blue to lavender-colored flowers.|
|Habitat||Coastal foredunes and coastal dune scrub communities.|
|Threats||Non-native plants, proposed residential and commercial development, hikers, and equestrians.|
Clover lupine, Lupinus tidestromii, a member of the pea family (Fabaceae), is a creeping perennial herb, 4-12 in (10-30 cm) tall. The above-ground parts are herbaceous. The technical description of the roots indicate that they are bright yellow but observers have not noted this characteristic from the northern plants. The narrow leaves have three to five leaflets, each 0.2-0.8 in (0.5-2 cm) long, and arranged in a fan shape. The stems and leaves have short hairs. The inflorescence stems are 1.6-3.1 in (4-8 cm) long, and the whorls of flowers are blue to lavender. The fruits are pods containing five to eight seeds with blackish spots. The characteristics that distinguish L. tidestromii from other lupines occurring in the area include the prostrate habit; the number of leaflets, usually three, and the small leaflet size; and the dense hairs on the foliage.
Clover lupine, which is also called Tidestrom's lupine, flowers more than once. Flowering occurs from May through June. Clover lupine is probably pollinated by bees. Within populations, plants exhibit highly congested distributions. Most clover lupine seeds can be found littered at the plant base. This and the large seed size is consistent with localized limited dispersal, and limited long-distance dispersal by abiotic factors. Seeds of clover lupine are generally long-lived and probably form a persistent dormant seed bank. For seeds to germinate under natural conditions, the seed coat probably must be degraded.
Clover lupine occurs on partially stabilized coastal dunes up to about 25 ft (7.5 m) high. Several occurrences on the Monterey Peninsula are on remnant dunes in the yards of private residences. It occurs in the mild maritime climate of the central California coast and grows in coastal dune communities in association with Menzies' wall-flower, sand gilia, beach evening-primrose, beach-bur, beach sagewort, sand verbena, and mock heather.
Clover lupine grows in stable to slightly mobile dunes, far from wind-blown habitats, so very slow microbial decomposition of seed coats of long-lived seeds is the more likely route to germination. This is not a species of accreting foredunes, and it has very low burial tolerance compared with larger dune plants of the pea family. As a result, clover lupine is confined to the vast stable deflation plains next to southern Abbotts Lagoon.
Clover lupine is restricted to coastal foredunes and is discontinuously distributed in three dune systems in two disjunct areas: the Monterey Peninsula in Monterey County, and northwest Marin County to the Russian River, Sonoma. Three occurrences of this species have been found in Point Reyes National Seashore, extending from Abbotts Lagoon to Point Reyes Test Station. Field studies by the California Native Plant Society have expanded the known limits of the three occurrences to include seven colonies in the dunes of Point Reyes. The southernmost occurrence is located at Pebble Beach in Monterey County. In 1996, this species was known from 19 extant occurrences with 433 individuals.
The major threats to clover lupine include invasion by non-native plants, such as iceplant and European beachgrass and loss of habitat due to development and trampling by hikers and equestrians. Livestock grazing may have been a threat in the past, but the only population grazed by livestock in recent years was a small one at Dillon Beach, which is probably extirpated. Two occurrences on the Monterey Peninsula were eliminated by construction of a golf course. Other occurrences on privately owned sites in Monterey are potentially threatened by residential and recreational development. At the time of listing the occurrences in Asilomar State Park and Point Reyes National Seashore were subject to trampling by hikers, a problem later corrected by controlled pedestrian routes.
Conservation and Recovery
The Pebble Beach Company set aside a 20-acre (8-hectare) reserve as mitigation for loss of sensitive species during the construction of the Spanish Bay Golf Course. Clover lupine was one of the species transplanted to this site in 1987, and monitoring is continuing.
U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
Eastside Federal Complex
911 N. E. 11th Ave.
Portland, Oregon 97232-4181
Telephone: (503) 231-6121
U. S. Fish and Wildlife Service. 22 June 1992. "Six Plants and Myrtle's Silverspot Butterfly from Coastal Dunes in Northern and Central California Determined to Be Endangered." Federal Register 57 (120): 27848-27858.