Galactia elliottii

Galactia elliottii
Photo by Karan A. Rawlins, University of Georgia, Bugwood.org
Scientific classification
Kingdom:	Plantae
Division:	Magnoliophyta - Flowering plants
Class:	Magnoliopsida - Dicotyledons
Order:	Fabales
Family:	Fabaceae ⁄ Leguminosae
Genus:	Galactia
Species:	G. elliottii
Binomial name
Galactia elliottii Nutt.
Natural range of Galactia elliottii from USDA NRCS Plants Database.

Common name: Elliott's milkpea

Description

G. elliottii is a perennial, viney, herbacious legume. Leaves are alternate and petiolate with inconspicuous, green stipules . It is a nitrogen fixing plant.

Generally, the genus Galactia are "trailing or twining, climbing, perennial, herbaceous or woody vines or erect, perennial herbs or rarely shrubs. Leaves 1-pinnate, usually 3-foliolate (or rarely 1-,5-7-,9-folilolate); leaflets entire, petiolulate, stipellate. Racemes axillary, pedunculate with few to numerous, papilionaceous flowers borne solitary or 2-several at a node, ech subtended by a bract and fusion of the 2 uppermost, with the laterals usually shorter than the uppermost and lowermost; petals usually red, purple, pink or white; stamens diadelphous or elsewhere occasionally monadelphous; ovary sessile or shortly stipitate. Legume oblong-linear to linear, few-many seeded, compressed, straight or slightly curbed, dehiscent with often laterally twisting valves.

Specifically, for Galactia elliottii they are "twining, climbing herbaceous vine or somewhat woody at base with sparsely to densely, antrorsely, retrorsely or spreading, strigillose to hirsute stems, 0.51-.5 m long. Leaves pinnately 7-9 foliolate; leaflets oblong to elliptic, 2-4 cm long, sparsely appressed short-pubescent to glabrous above and moderately to densely strigillose beneath. Racemes with peduncles and rachises sparsely to densely, retrorsely, strigillose to somewhat spreading hirsute, 5-20 cm long; flowers 1-3 at each node on usually densely and retrorsely short-hirsute pedicels 1-2.5 mm long. Calyx appressed to somewhat spreading strigillose to short-pilose, tube ca. 3 mm lon, lobes 7-10 mm long; petals white or tinged with red, the standard 1.2-1.5 cm long. Legume 3.5-5 cm long, 5-8 cm long, 5-8 mm broad, densely appressed- tomentose."

Distribution

It is native to South Carolina, Georgia and Florida (Muir and Pitman 1987).

Ecology

Habitat

In the Coastal Plain in Florida, G. elliottii can be found in pine flatwoods, sandy scrub, dry pine woods, and mesic transition zones between scrubs and seepage forests. In disturbed areas it has been found in railroad gravel and in coarse sandy roadsides amongst grasses (FSU Herbarium). It is often found in Spodosol soils (Muir and Pitman 1987). Associated species include Croton glandulosus, Paspalum notatum, and Sporobolus virginicus (FSU Herbarium).

Many legume species are light sensitive, yield decreases as shade increases. However, G. elliottii possesses and adaptation to shade by producing more herbage and seed under partial shade than full sunlight (Muir and Pitman 1989).

G. elliottii is a nitrogen fixing legume and requires relatively high concentrations of other nutrients such as phosphorus and iron (Hungate et al. 2004). Phosphorus has been found to enhance yield of herbage and roots (Muir and Pitman 1989).

Phenology

The white flowers have diadelphous stamens, and can be observed blooming May through June (FSU Herbarium).

G. elliottii naturally senescences during autumn months, this is a grazing management strategy to defer autumn grazing allowing depleted plants to restore vigour (Muir and Pitman 1991). It has been found to not be tolerant of repeated defoliation because this species persists primarily through survival of individual plants and vegetative propagation.

Fire ecology

In fire suppressed scrubby flatwoods, it can become overgrown and be a dominant understory species (Silva-Lugo and Tanner 2010). Schmalzer and Hinkle (1992) found that G. elliottii has a seasonal response to fire, present in June (6 and 18 months postburn) and not in winter.

Pollination

The following Hymenoptera families and species were observed visiting flowers of Galactia elliottii at Archbold Biological Station.

Halictidae: Halictus poeyi, Nomia maneei

Megachilidae: Anthidiellum notatum rufomaculatum, Megachile exilis parexilis, M. georgica, M. mendica, M. petulans

References and notes

Florida State University Robert K. Godfrey Herbarium database. URL: http://herbarium.bio.fsu.edu. Last accessed: October 2015. Collectors: Loran C. Anderson, Edwin L. Bridges, R.K. Godfrey, Ed Keppner, Lisa Keppner, Robert A. Norris, Steve L. Orzell. States and Counties: Florida: Bay, Highlands, Nassau, Polk, St. Johns, Taylor, Volusia. Compiled by Tall Timbers Research Station and Land Conservancy.

J. A. Langley, B. G. Drake, and B. A. Hungate. “Extensive Belowground Carbon Storage Supports Roots and Mycorrhizae in Regenerating Scrub Oaks”. Oecologia 131.4 (2002): 542–548. Web...

J. P. Muir, and W. D. Pitman. “Improving Germination Rate of the Florida Legume Galactia Elliottii”. Journal of Range Management 40.5 (1987): 452–454

Muir, J. P. and W. D. Pitman (1989). "Response of the Florida legume Galactia elliottii to shade." Agroforestry Systems 9(3): 233-239.

Muir, J.P. and W.D. Pitman (1991). "RESPONSES OF DESMANTHUS-VIRGATUS, DESMODIUM-HETEROCARPON, AND GALACTIA-ELLIOTTII TO DEFOLIATION". Journal of Tropical Grasslands 25(3):291-296.

Schmalzer, Paul A., and C. Ross Hinkle. “Recovery of Oak-saw Palmetto Scrub After Fire”.Castanea 57.3 (1992): 158–173.

Silva-Lugo, Jose L., and George W. Tanner. “Testing Control Sites for Fire Ecology Research”.Journal of the Torrey Botanical Society 137.2/3 (2010): 263–276.