Andropogon

Andropogon

Pictured from left to right: Andropogon gerardii (2 photos) and Andropogon hallii (2 photos)

Andropogon

This genus is probably one of the best known of our native grasses. The inflorescence is one of the distinctive features, being a terminal cluster of pubescent spike-like branches, each up to 1 dm long. Spikelets are paired at each node; one sessile and fertile, the other on a pubescent pedicel and either staminate or sterile. The fertile spikelet has only 2 florets though only the upper is fully fertile.

There are 2 species in MN; 1 is native.

Common species:

Andropogon gerardii (an dro po' gun jeh rar' dee eye)

  • Synonyms: None
  • Common names: big bluestem, turkey-foot; Lakota: peji sasa okihe tankinkinyan; Ojibway: muckode' kanes
  • Origin and habitat: Native; dry prairies and other open habitats, also along forest edges
  • Identifying characters: Stems have purplish nodes and near the base of the plant purplish internodes (hence one of the common names). Lower leaves have long hairs on the blade at the collar area with the very lowest leaves often pubescent on the sheath as well. Young plants can be very hairy with folded leaves, giving these plants a flattened or keeled feel. Ligules are short (1-2.5 mm) and minutely pubescent on the back with cilia on the margins. Lemmas have a long twisted terminal awn.
  • Comments: Big bluestem is the quintessential tall-grass prairie plant. Pioneer diaries and reports mention riding across the open prairies with this plant being as tall as horses' backs. Seedlings develop rapidly and can reach 18 inches tall just in the first year. Horticulturally, this is becoming a choice ornamental as a foundation or specimen plant. Related species in Europe are a source of citronella oil and other fragrances; Ojibway used big bluestem roots in a decoction for stomach pains. Also known as a good pasture grass although heavy continuous grazing can decrease its abundance. There isn't much else in our flora that would be confusing. 

The other species reported for Minnesota, A. hallii or sand bluestem, is a native of the Great Plains on sandy soils. It is reported only from Goodhue and Sherburne counties, probably introduced in roadside plantings but now persisting. Sand bluestem differs in being less densely clustered, leaves with longer ligules, bright yellow internodes, and yellowish hairs in the somewhat broader inflorescense.

Maps
andropogon gerardiiAndropogon hallii
  

Additional species in Minnesota:
A. hallii