Stylosanthes guianensis Seeds | Stylo
LATIN NAME: Stylosanthes guianensis
COMMON NAME: Stylo
Plant Profile
Stylo is a low, spreading perennial legume of tropical America, with narrow, three-part leaves and small yellow pea flowers hidden among the foliage. It forms a dense mat thirty to sixty centimetres deep that stands grazing, drought and the acid soils that defeat most pasture plants.
It was carried around the world’s dry tropics as a pasture legume and is now a mainstay of cattle country from Brazil to Queensland and northern Thailand. On the farm it is grown for what it does to the soil as much as for what it feeds: nitrogen fixed in nodules, ground covered, weeds shaded out. The yellow flowers sit in tight heads and are easily missed from a distance, which is why the plant reads as a leaf crop rather than a flowering one in the field.
Science & Biotechnology
Its recent history is a lesson in plant breeding under pressure: the anthracnose fungus Colletotrichum destroyed the leading cultivars across South America and Australia in the late 1970s and 1980s, and replacements had to be bred for resistance in a running race with the pathogen. The episode is a standard case study in forage-legume breeding.
The seed is hard-coated and scarification is standard practice, and the species carries bristly, sticky stems that trap small insects, a family trait put to work in some cultivars as a natural pest trap in pastures. The sticky stems have drawn separate attention as a possible source of natural adhesives, and the resin they exude has been characterised in materials work.
Uses & Benefits
It is sown into grass pasture to lift the protein content of the feed through the dry season, cut for hay, and used as a soil-improving fallow on exhausted tropical ground. In gardens of the warm tropics it serves as a low, flowering groundcover in poor, acid soil where little else holds.
For the small grower it is one of the most practical legumes available: easy from scarified seed, undemanding in soil, and it keeps working after the rains stop. Its leaf meal is also dried and sold as a protein supplement in regions where soybean meal is expensive, which keeps the species in the agricultural economics papers.
Growing from Seed
Rub the seed between sandpaper or soak it in hot water overnight before sowing; the hard coat is the whole obstacle.
Sow a centimetre deep in warm soil or a free-draining mix at 25 °C; germination takes one to two weeks.
Give it full sun and ordinary to poor soil, water to establish, and then let it spread; it stands cutting or grazing once the roots are down, and a phosphate dressing at establishment pays for itself in the first season. In its second season a stand closes into a solid mat, and from then on it needs nothing beyond the occasional phosphate top-up to hold its nitrogen supply.
Our Take
The working legume of the dry tropics: yellow flowers in a grazed mat, nitrogen in the soil and a cultivar history every breeder should read.
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