Tripsacum dactyloides
(eastern gamagrass)

Preferred Common Name

• eastern gamagrass

Other Scientific Names

• Coix angulata Mill.
• Coix dactyloides L.
• Dactylodes angulatum Kuntze
• Dactylodes dactyloides (L.) Kuntze
• Ischaemum glabrum Walter
• Tripsacum bravum J.R.Gray
• Tripsacum floridanum Porter ex Vasey
• Tripsacum monostachyon Willd.

International Common Names

• English: bullgrass; eastern mock grama; fakahatchee grass; gamagrass; northern gamagrass; sesame grass; wild corn
• Spanish: maicillo oriental; pasto Guatemala; zacate maicero
• French: herbe de gama; herbe grama; maicillo oriental

Local Common Names

• Brazil: capim gigante
• Cuba: zacate
• Dominican Republic: lagon
• Germany: Gamagras; Gama-Gras
• Haiti: herbe rasoir
• Mexico: zacate maicero

EPPO code

• TRWDA (Tripsacum dactyloides)

• Domain: Eukaryota
•     Kingdom: Plantae
•         Phylum: Spermatophyta
•             Subphylum: Angiospermae
•                 Class: Monocotyledonae
•                     Order: Cyperales
•                         Family: Poaceae
•                             Genus: Tripsacum
•                                 Species: Tripsacum dactyloides

Poaceae is one of the largest families of flowering plants comprising 707 genera and more than 11,300 species distributed worldwide (Stevens, 2012). The genus Tripsacum contains 14 species, which occur from temperate North America to Paraguay in South America (Zuloaga et al., 2003; Clayton et al., 2017; Missouri Botanical Garden, 2017). Tripsacum is closely related to Zea, the genus containing the cultigen maize and its wild relatives known as 'teosintes'. These two genera share a number of morphological features, including the highly specialized cupulate fruitcase and the spikelet arrangement. They also have the potential to cross and produce viable but typically infertile hybrids.  Because of their affinity to maize, Tripsacum species have been the subjects of numerous evolutionary, taxonomic and biosystematics studies and many cultivars have been developed (Doebley, 1983; Cook et al., 2005, USDA-NRCS, 2017).

The following description is from Cook et al. (2005): An extremely variable perennial clump grass, with short, fibrous, knotty rhizomes and deep, hollow roots. Culms 2-3 (-4 m) tall, and 3-5 cm thick at base, branching, prop-rooting from lower nodes; stems purplish, glabrous. Leaf sheath glabrous, often purplish; leaf-blade lanceolate-acuminate, up to 1.5 m long and 9-35 mm wide, mostly glabrous, sometimes hairy at the base of the upper blade surface; margin scabrous; ligule a fringe of hairs, 1-1.5 mm long, prominent midrib. Inflorescence 10-20 (-30) cm long, terminal and axillary, commonly a single raceme, or subdigitate panicle comprising 2-3 (-6) racemes of usually unisexual awnless spikelets (gynomonoecious types have been found); the female (pistillate) spikelets (green when immature), occupying the basal one-eighth to one-third of the raceme, inserted singly and alternately on opposite sides of the thick, hard articulate lower part of the rachis, sunken in hollows in the joints; oval in section, hard, separating into bead-like segments 7-10 mm long at maturity: the male (staminate) spikelets 7-11 mm long (purplish when immature) inserted in pairs at either side of oblique nodes, and on one side of the flattened rachis at the terminal end of the raceme; anthers cream to orange, stigmas white to purple, up to 2.5 cm long.

Tripsacum dactyloides has been introduced as a forage crop. It is also cultivated as a hay and silage crop, for soil conservation, and for erosion control. Across the United States, interest in T. dactyloides increased significantly during the late 1980s and early 1990s, mainly due to its ability to produce large quantities of high quality forage during the summer months (USDA-NRCS, 2017). In Malaysia, this species has been extensively planted on rubber estates as a soil conditioner in drained swamps, and for mulching (Gilliland, 1971; FAO, 2017).

Soil drainage

• free
• seasonally waterlogged

Soil reaction

• acid
• neutral

Soil texture

• light
• medium

Natural Dispersal

Tripsacum dactyloides spreads by seeds. The species may yield 12,000-15,000 seeds/kg (Cook et al., 2005).

Intentional Introduction

Tripsacum dactyloides has been intentionally introduced as a forage, hay and silage crop. It is cultivated in areas within and outside its native distribution range (USDA-NRCS, 2017).  

Tripsacum dactyloides forms extensive and persistent stands which have the potential to outcompete and displace native species (USDA-ARS, 2017; USDA-NRCS, 2017). The species is only listed as invasive in Cuba (Oviedo-Prieto and Gonzalez-Oliva, 2015), but there is a lack of information about its competition strategies and the negative impacts associated with the occurrence of this invasive species in Cuba.

• Proved invasive outside its native range
• Has a broad native range
• Abundant in its native range
• Highly adaptable to different environments
• Is a habitat generalist
• Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
• Benefits from human association (i.e. it is a human commensal)
• Long lived
• Gregarious
• Reproduces asexually

• Ecosystem change/ habitat alteration
• Monoculture formation

• Competition - monopolizing resources
• Competition - smothering
• Hybridization

• Highly likely to be transported internationally deliberately
• Difficult/costly to control

Economic Value

Tripsacum dactyloides is cultivated for forage, fodder, hay and silage, for soil conservation, and as an ornamental. The species is often used as a forage crop because its growing season starts earlier than other warm-season grasses and later than cool-season grasses and legumes. It is also palatable and easily digestible by cattle (Cook et al., 2005; USDA-ARS, 2017). 

Environmental Services

Tripsacum dactyloides assists the infiltration of water and improves soil physical and hydraulic properties. Consequently, this species is recommended for filter strips along the edges of agricultural fields, to enhance infiltration and reduce surface runoff. It is also used as a vegetative barrier for soil erosion control and revegetation (Cook et al., 2005; Missouri Botanical Garden, 2017; USDA-NRCS, 2017; USDA-ARS, 2017).