Andropogon ternarius

Common name: Splitbeard Bluestem

Andropogon ternarius
Andropogon ternarius taken by Kevin Robertson
Scientific classification
Kingdom:	Plantae
Division:	Magnoliophyta - Flowering plants
Class:	Moncots or Dicots
Order:	Cyperales
Family:	Poaceae/Gramineae
Genus:	Genus
Species:	A. ternarius
Binomial name
Andropogon ternarius Michx.
Natural range of Andropogon ternarius from USDA NRCS Plants Database.

Taxonomic notes

Synonyms: Andropogon ternarius var. ternarius; A. ternarius; A. ternarius var. ternarius; A. ternarius var. glaucescens (Scribner) Fernald & Griscom

Description

Annual, tufted grass, 5 ft tall. NinaRaymond

Cespitose or tufted perennial that comes from hardened bases or short rhizomes. The culms are usually glaucous and sometimes purple in color. The nodes and internodes are usually glabrous. The leaves are basal and cauline. The blades are scaberulous, frequently hirsute or pilose on the upper surface above the ligule. The sheaths are keeled, the margins are scarious, the ligules are membranous, erose or ciliolate, and 0.5-1.5mm long. The collars are glabrous or hirsute. There are numerous racemes that are pedunculated, exserted or inserted in subtending sheaths. The spikelets are in pairs, sessile fertile, pedicellate either staminate, reduced or absent. The glumes are usually scaberulous, subequal, acute to aristate, the first are keeled and somewhat scarious, the second is usually sulcate and somewhat cartilaginous. There are fertile and sterile lemmas hyaline that are subequal that are shorter than glumes. The fertile lemma are awned. The paleas are hyaline and are reduced. The callus beard is usually longer than the spikelet. The grain is purplish or yellowish in color, is linear-ellipsoid in shape, and 2-3mm long. (Radford 1964).

The culms are 0.7-1.5m tall. The blades are 3dm long and 2-3.5mm wide. There are 2-3 racemes that are villously white and are 1.5-4cm long. The rachis joins and pedicels are densely villous and are 3-10mm long. The peduncles are exserted and are 4-15cm long; sheaths are tight. The fertile spikelet are 5-5mm long, exceeding rachis joint. The lemma awn is slightly twisted and is 1.5-2.5cm long. The sterile spikelet and pedicel are equal and a little longer than the fertile spikelet, the pedicel is flat. Flowers from September to October. (Radford 1964).

Ecology

Habitat

In the Coastal Plain in Florida and Georgia, Andropogon ternarius has been found in pine/oak sandhills, pine scrubs, turkey oak scrubs, upland pine forests, river banks, and pine flatwoods. It can occur in disturbed areas such as roadsides, recreation areas, cut-over pinewoods, gas line corridors, slash pine plantations, old fields and cultivated fields (FSU Herbarium). Associated species include Pteridium, Crataegus lacrimata, Psoralea lupinellus, Aristida purpurascens, Sorghastrum elliottii, Eragrostis hirsuta, Dichanthelium, and Muhlenbergia expansa (FSU Herbarium). Soil types include sand, loamy sand, loam, sandy alluvium, and sandy loam (FSU Herbarium).

Phenology

Flowers and fruits May through November (FSU Herbarium).

Fire ecology

A. ternarius has been recorded in annually burned upland pines and pine savannas (FSU Herbarium).

References and notes

Florida State University Robert K. Godfrey Herbarium database. URL: http://herbarium.bio.fsu.edu. Last accessed: October 2015. Collectors: Jame Amoroso, Loran Anderson, Wilson Baker, Kathleen Craddock Burks, A.F. Clewell, A.H. Curtiss, R. K. Godfrey, D. C. Hunt, R. Komarek, R. Kral, Karen MacClendon, Travis MacClendon, Sidney McDaniel, Marc Minno, Richard S. Mitchell, J. Roche, Cecil R. Slaughter, George Wilder, Jean W. Wooten, Bian Tan. States and Counties: Florida: Baker, Bay, Dixie, Duval, Calhoun, Columbia, Escambia, Franklin, Gadsden, Gilchrist, Jackson, Jefferson, Lake, Leon, Liberty, Madison, Marion, Okaloosa, Taylor, Walton, Wakulla. Georgia: Grady, Thomas. Compiled by Tall Timbers Research Station and Land Conservancy.

Radford, Albert E., Harry E. Ahles, and C. Ritchie Bell. Manual of the Vascular Flora of the Carolinas. 1964, 1968. The University of North Carolina Press. 162-163. Print.