White Birds-in-a-nest

Macbridea alba

Description

White birds-in-a-nest is an upright, usually single-stemmed, odorless perennial herb with fleshy rhizomes. This mint is about 1 ft-1.3 ft (30-40 cm tall with opposite leaves up to 4 in (10 cm long, 0.4-0.8 in (1-2 cm) broad, with winged petioles. All the plants at a site will be either glabrous or pubescent. The clustered flowers are in a short spike with bracts. Each flower has a green calyx about 0.4 in (1 cm) long and a brilliant white corolla 1.2 in (3 cm) long. The corolla is two-lipped, and the upper lip hooklike. In flower, white birds-in-a-nest is conspicuous and unmistakable.

Habitat

This species is restricted to the Gulf coastal lowlands near the mouth of the Apalachicola River. This species inhabits grassy vegetation on poorly drained, infertile sandy soils. The wettest sites are grassy seepage bogs on gently slopes at the edges of forested or shrubby wetlands. This species also inhabits grass-sedge bogs (savannahs), which are nearly treeless and shrubless but have a rich flora of grasses, sedges and herbs. White birds-in-a nest also occurs in scrubby oak vegetation near the shoreline of the Gulf of Mexico.

Grassy savannahs and bogs are maintained by periodic fires. Lightning fires usually occur during the growing season. Fire during the growing season can stimulate and/or synchronize flowering in many species. The Apalachicola region has many endemic plant species, most of them are native to savannahs.

Savannahs have a greater economic value when they are planted with pine trees or converted to pasture. Prior to planting pines, the site is prepared by bedding and using other mechanical methods which are destructive to the vegetation.

This species is associated with the Eastern Gulf Coast Flatwoods. The Kuchler system places this species habitat within the longleaf-slash pine ecosystem, restricted to flat and irregular southern Gulf Coastal Plains. Local relief is less than 300 ft (100 m). Much of this area is forested. The elevation ranges from sea level to 75 ft (22.5 m). This nearly level low coastal plain is crossed by many large streams, lakes, and ponds. The average annual precipitation is 53-65 in (1,325-1,625 mm). The abundant rainfall and the many perennial streams are important sources of water. The dominant soils are Aquults, Aquepts, and Aquods. These soils have a thermic temperature regime and an aquic moisture regime. They are, also, sandy and poorly drained or very poorly drained.

This area supports pine forest vegetation. Chalky bluestem, indian grass, and several Panicum species make up the understory. Palmetto, gallberry, and waxmyrtle are the dominant woody shrubs. Longleaf and slash pine are the major trees. The fauna associated with longleaf-slash pine forest include the white-tailed deer, raccoon, the opossum, tree squirrels, rabbits, and numerous species of ground-dwelling rodents. The bobwhite and the wild turkey are the principal gallinaceous game birds. Resident and migratory nongame bird species are numerous, as are migratory waterfowl.

Distribution

White birds-in-a-nest occurs in Bay, Gulf, Franklin, and Liberty Counties, Florida. The Apalachicola National Forest has the most vigorous populations, with the largest numbers of individuals. Exact population numbers are not known, but a plant inventory conducted by the Florida Natural Areas Inventory listing "occurrences" recorded more occurrences than are now thought to be extant. Forty-one of 63 reported localities are in the Post Office Bay area of Apalachicola National Forest.

Threats

This species has fallen vulnerable to habitat degradation due to lack of prescribed fire and forestry practices.

Development of improved cattle pastures has probably destroyed habitat of this species. The forest products industry has modified habitat by planting and harvest of slash pine and by the USDA Forest Service planting of longleaf pine. Site preparation that precedes tree planting may destroy plants. Shading of this species by neighboring grasses and by pine trees after canopy closure most likely adversely affects the species.

Landowner liability for fire has discouraged prescribed burning of pineland in Florida which, also, may have adversely affected this species. The Forest Service conducts some prescribed burns during the growing season to reduce the incidence of brown-spot infection of longleaf pine seedlings.

Five of 22 known sites are on highway right-of-ways posing a threat if the roads were ever widened.

Conservation and Recovery

Conservation measures provided to species listed as endangered or threatened pursuant to the Act include recognition, recovery actions, requirements for federal protection, and prohibitions against certain practices. Recognition through listing encourages conservation measures by federal, international, and private agencies, groups, and individuals.

Contacts

U.S. Fish and Wildlife Service
Office of the Regional Director
1875 Century Boulevard, Suite 400
Atlanta, Georgia 30345-3319
Telephone: (404) 679-4000
Fax: (404) 679-4006

U.S. Fish and Wildlife Service
Panama City Ecological Services Field Office
1612 June Avenue
Panama City, Florida 32405-3792
Telephone: (850) 769-0552
Fax: (850) 763-2177

Reference

U.S. Fish and Wildlife Service. 8 May 1992. "Endangered and Threatened Wildlife and Plants; Threatened Status for Three Florida Plants." Federal Register 57 (90): 19813-19819.