Stylosanthes macrocephala M.B. Ferreira
& N.M. Sousa Costa

Leguminosae

Macrocephala

S. macrocephala originates in central and eastern Brazil and it has been introduced to other tropical countries.

A perennial, fine-stemmed, many-branched, and taprooted subshrub, prostrate to semi-erect, 20-80 cm tall; stems and branches hairy-bristly. Leaves tri-foliolate; stipules obovate, 14-16 mm x 5-6 mm, with pointed teeth, pubescent to glabrous or bristly, with 11-13 pairs of veins; petiole 1-2 mm long, villous; leaflets lanceolate, 20-55 mm x10-19 mm, pubescent or glabrous, with 7-10 pairs of veins. Inflorescence a capitate spike, terminal or axillary, ovoid to almost spherical, 14-18 mm x 10-15 mm, with 10-30 flowers; often several inflorescences in a cluster; bracts imbricate, uni-foliate, elliptical-ovate, 10-12 mm x 8-9 mm, pubescent, with 11-15 veins, reddish; flowers papilionaceous, small, with obovoid standard 4-6 mm long, yellow, striated; axis rudiment and 2 inner bracteoles present. Fruit 2-articulated, reticulately nerved; both articles usually fertile; the upper one glabrous, 3-4 mm x 2.5-3 mm, with a short, straight to uncinate beak; lower article villous and smaller. Seed yellow-brown, sometimes slightly mottled, to black (Schultze-Kraft 1992).

S. macrocephala is used as forage in permanent pastures grazed by ruminants. Cultivar 'Pioneiro' has been released in Brazil for use in the Cerrados savanna region.

In many regards, S. macrocephala is similar to S. capitata Vogel. Its nutritive value, however, is higher: in 6-week-old regrowth, N concentrations in leaves range from 2.2% - 3.5% (stems: 1.4-1.8%), and leaf DM digestibility from 66% - 75% (stems: 46-61%); P concentrations are moderate to low, 0.17-0.25% in leaves and 0.13-0.25% in stems. There are about 500 seeds (dehulled pods)/g (Schulze-Kraft 1992).

None has been reported.

Its natural distribution is restricted to sub-humid and dryland savanna environments.

Soil requirements

Tolerant of acid, low-fertility oxisols and ultisols. Its productivity is enhanced by fertilization.

In many respects S. macrocephala is similar to S. capitata. Newly harvested seed may have to be treated to reduce hard-seededness. It is sown at 4 – 5 kg/ha. It is somewhat less productive than S. capitata, during both the rainy and dry seasons. Seed set and seedling recruitment are essential for long-term persistence.

S. macrocephala nodulates effectively with native rhizobia.

Like S. capitata, S. macrocephala persists through extensive seedling recruitment. It is a prolific seeder.

S. macrocephala is more anthracnose-tolerant than other Stylosanthes species. In Colombia, it can be seriously affected by Rhizoctonia foliar blight.

Performance

Dry matter yields of up to about 4000 kg/ha have been recorded in Brazil, on an acidic, low fertility, quartz-sandy soil fertilized with 300 kg/ha lime, 200 kg/ha of simple superphosphate and 50 kg/ha potassium chloride (Miranda et al. 1999). On a sandy soil in Corrientes, Argentina it produced 6.4 t/ha dry matter (Ciotti et al. 1999). However, unless more productive cultivars with better dry-season performance become available, the potential role of S. macrocephala for pasture development will most likely be limited, as S. capitata is an equally well-adapted but more productive species (Schultze-Kraft 1992).

Links

• FAO Tropical Feeds: Nutritive characteristics of Stylosanthes macrocephala

Links for the genus

• Plant Protection Society of WA: description of various Stylosanthes species

References

Ciotti E. M. et al. (1999); Miranda C. H. B. et al.(1999); Schultze-Kraft R. (1992)