Belongs within: Andropogoneae.
Contains: Hyparrhenia, Schizachyrium.
The Andropogoninae are a clade of grasses united by molecular data but lacking clear morphological synapomorphies. The greater number of species are included in Andropogon, a tropical and subtropical genus of erect grasses bearing panicle-like inflorescences (Hickman 1993).
High grasses of the hot zone
Published 14 February 2025
The grasses are without question one of the most significant groups of plants in shaping our current world. Certain genera of grasses particularly stand out as characterising the habitats in which they are found; in warmer regions of the world, these include species of the genus Andropogon.
Over one hundred species of grasses are currently attributed to Andropogon, with representatives found worldwide. Most are tussock-forming perennials with some species growing spectacularly tall. Gamba grass A. gayanus, a prominent species of African savannahs, may reach four metres in height. Andropogon species produce unbranched or digitate inflorescences comprised of a series of spikelets arranged in pairs; each pair comprises one sessile spikelet and one produced on a pedicel. The sessile spikelet is bisexual; the pedicellate spikelet is staminate or sterile. In some cases, the pedicellate spikelet is reduced to its glume only or is absent, leaving only the bare pedicel (Kellogg 2015). When the seed is ripe, the inflorescence breaks between each pair that fall to the ground as a unit.
Where they grow, Andropogon species may form dense patches that out-compete rival species. The aforementioned gamba grass dominates regions of Africa with long dry seasons. Big bluestem A. gerardi is prominent in North American prairies. A number of species are regarded as desirable fodder for livestock; they may also be grown as ornamentals or used in revegetation. However, not all Andropogon species are regarded as desirable. After being introduced to the country for forage, gamba grass has come to be regarded as a declared weed in Australia due to its negative impact on native vegetation. Conversely, some species are localised or even endangered; the southern Brazilian species A. barretoi is currently restricted to a stretch of some ten miles alongside the road between Santa Maria and Porto Alegre (Nagahama & Norrmann 2012).
Over four hundred species have been assigned to Andropogon in the past before the recognition of multiple segregate genera. Even with that winnowing down, Andropogon as currently recognised is probably polyphyletic (Welker et al. 2020). As with other grasses, understanding the relationships between species is complicated by high rates of hybridisation and polyploidy; time will tell how Andropogon comes to be treated.
Beyond Andropogon
Published 18 January 2026
Having considered Andropogon, it might be worth turning some attention to its relatives. Andropogon forms the greater part of a clade recognised by Welker et al. (2020) as the Andropogoninae (if not the scope—as I noted previously, Andropogon as currently recognised is not monophyletic and is not impossible that all other andropogonine genera represent derived segregates). Prior to Welker et al. (2020), this clade was sometimes referred to as the ‘DASH clade’ in reference to four constituent genera: Diheteropogon, Andropogon, Schizachyrium and Hyparrhenia.
Though supported molecularly, Welker et al. (2020) did not identify any morphological synapomorphies for their Andropogoninae. Kellogg (2015), who recognised ‘Andropogoninae’ in a broader sense, noted that members had the upper lemma (one of the bracts around a floret) awned from the apex or from a sinus, and the awn was generally geniculate (jointed). Genera have commonly been separated by branching patterns of the inflorescence. The two largest genera, Andropogon and Schizachyrium, are united by the absence of epidermal papillae on the leaves; the inflorescence is unbranched in Schizachyrium vs the branched inflorescences of many Andropogon species. The remaining genera of andropogonines are most diverse in Africa. The pantropical Diectomis fastigiata is awarded its own genus, and bears unbranched inflorescences including pedicellate spikelets with broad glumes (surrounding bracts). Hyparrhenia, another fairly large genus, bears two-branched inflorescences with one branch slightly longer than the other. Two-branched inflorescences are also found in the genera Exotheca and Hyperthelia; the shorter branch in these genera bears spikelets along almost the entire length but the longer branch bears spikelets only in the distal half.
The larger species of Andropogoninae in Africa are commonly known as ‘thatching grasses’ in reference to their use in thatching roofs. Some species of Schizachyrium, known as bluestems, are cultivated as ornamentals. There are also a number of andropogonine species that are valued as fodder for livestock, and some have been spread outside their native ranges as a result. Of course, some of these species have then become maligned as invasives in their new homes, so their reputation is all a matter of context.
Systematics of Andropogoninae
<==AndropogoninaeK15
|--Bhidea Stapf ex Bor 1949K15
| `--B. fischeri Sreekumar & Shetty 1987SY02
`--+--Pseudodichanthium Bor 1940K15
| `--P. serrafalcoidesK15
`--Andropogon L. 1753K15 [incl. GymnandropogonB78, Hypogynium Nees 1829WM20, K15]
| i. s.: A. affinisB78
| A. bicornisJ87
| A. brevifoliusMB08
| A. capillipesM83
| A. condensatusS06
| A. consanguineusS06
| |--A. c. var. consanguineusS06
| `--A. c. var. humilior Hack. in Mart. & Eichl. 1883S06
| A. densiflorusD17
| A. erianthoidesB78
| A. flabellifer Pilger 1917P17
| A. foveolatusCS77
| A. glaucophyllusK15
| A. glomeratusJ87
| |--A. g. var. glomeratusJ87
| |--A. g. var. pumilusJ87
| `--A. g. var. scabriglumisH93
| A. hypogynusK15
| A. imberbisS06
| A. intermedius [incl. A. inundatus]B78
| A. intumescens Pilger 1910 [incl. Ischaemum brachyatherum]P17
| A. kelleriTGL-S08
| A. lateralisRJ11
| A. leucostachyusJ87
| A. lividusS03
| A. longipesS03
| A. macrothrixS06
| A. muricatumFS90
| A. nutansS06
| |--A. n. var. nutansS06
| |--A. n. var. agrostoides [=A. agrostoides Speg. 1883]S06
| |--A. n. var. avenaceusS06
| |--A. n. var. pellitusS06
| `--A. n. var. stipoidesS06
| A. paniculatusS06
| |--A. p. var. paniculatusS06
| `--A. p. var. elongatus Hackel in Stuckert 1906 [=A. condensatus var. elongatus]S06
| A. saccharatumS06
| A. saccharoidesBB01
| | i. s.: A. s. var. imperatoidesS06
| | A. s. var. laguroidesS06
| | A. s. var. torreyanusM68
| |--A. s. ssp. saccharoidesS06
| `--A. s. ssp. leucopogonS06
| |--A. s. ssp. l. subvar. leucopogonS06
| `--A. s. ssp. l. subvar. perforatusS06
| A. sorghumS06
| |--A. s. var. sorghumS06
| |--A. s. var. cernuusS06
| `--A. s. var. vulgarisS06
| A. squarrosusS06
| A. tenerS06
| A. virginicusRJ11
|--+--+--A. ivorensisWM20
| | `--+--Pseudanthistiria (Hack.) Hook. f. 1896K15
| | `--Diheteropogon (Hack.) Stapf 1922WM20, K15
| | |--D. amplectensWM20
| | `--D. hagerupiiWM20
| `--+--+--HyparrheniaWM20
| | `--+--A. greenwayiWM20
| | `--A. leprodesWM20
| `--+--*A. distachyosWM20
| |--A. abyssinicusWM20
| |--A. manniiWM20
| `--A. pusillusWM20
`--+--+--+--A. gerardiWM20
| | `--A. halliiWM20
| `--+--A. heterantherusWM20
| `--+--SchizachyriumWM20
| `--+--+--A. canaliculatusWM20
| | `--+--A. chinensisWM20
| | `--A. schirensisWM20
| `--+--A. gayanusWM20
| | |--A. g. var. gayanusK15
| | `--A. g. var. bisquamulatusK15
| `--Anadelphia Hack. 1885WM20, K15 (see below for synonymy)
| |--A. fasciculata [=*Diectomis fasciculata]K15
| |--A. leptocoma [incl. Andropogon tenuiflorus Stapf 1905, Ana. virgata Hack. 1885]P17
| `--A. scyphoferaWM20
`--+--+--Diectomis Kunth 1815 (nom. cons.)WM20, K15
| | `--*D. fastigiataK15
| `--+--‘Schizachyrium’ tenerumWM20
| `--+--‘Schizachyrium’ ursulusWM20
| `--+--A. reediiWM20
| `--+--‘Schizachyrium’ cirratumWM20
| `--+--A. ingratusWM20
| `--+--‘Schizachyrium’ imberbeWM20
| `--+--A. hondurensisWM20
| `--‘Schizachyrium salzmanniiWM20
`--+--‘Schizachyrium’ tholloniiWM20
`--+--A. brazzaeWM20
`--+--Elymandra Stapf 1919WM20, K15 [incl. Pleiadelphia Stapf 1927K15]
| |--+--E. grallataWM20
| | `--E. subulataWM20
| `--+--*E. androphilaWM20
| `--Monocymbium Stapf 1919WM20, K15
| |--*M. ceresiiformeWM20
| `--M. lanceolatumWM20
`--+--+--A. huillensisWM20
| `--+--A. aequatoriensisWM20
| `--+--A. glaucescensWM20
| `--A. insolitusWM20
`--+--A. appendiculatusWM20
`--+--A. ligulatusWM20
`--+--A. laxatusWM20
`--+--+--A. eucomusWM20
| `--A. selloanusWM20
`--+--+--A. liebmanniiWM20
| `--A. urbanianusWM20
`--+--A. floridanusWM20
`--+--A. gyransWM20
`--A. mohriiWM20
Anadelphia Hack. 1885WM20, K15 [incl. Diectomis Beauv. 1812 (nom. rej.) non Kunth 1815K15, Monium Stapf 1919K15, Andropogon sect. Pobeguinea Stapf 1905K15, Pobeguinea (Stapf) Jacq.-Fél. 1950K15]
*Type species of generic name indicated
References
[BB01] Bauer, R., D. Begerow, A. Nagler & F. Oberwinkler. 2001. The Georgefischeriales: a phylogenetic hypothesis. Mycological Research 105 (4): 416–424.
[B78] Bentham, G. 1878. Flora Australiensis: A description of the plants of the Australian Territory vol. 7. Roxburghiaceae to Filices. L. Reeve & Co.: London.
[D17] Diels, L. 1917. Beiträge zur Flora der Zentral-Sahara und ihrer Pflanzengeographie. Nach der Sammelausbeute des Freiherrn Hans Geyr von Schweppenburg. Botanische Jahrbücher für Systematik, Pflanzengeschichte und Pflanzengeographie 54 (Beiblatt 120): 51–155.
[FS90] Fleutiaux, E., & A. Sallé. 1890. Liste des coléoptères de la Guadeloupe et descriptions d’espèces nouvelles. Annales de la Société Entomologique de France, 6e série 9: 351–484.
[H93] Hickman, J. C. (ed.) 1993. The Jepson Manual: Higher Plants of California. University of California Press: Berkeley (California).
[J87] Judd, W. S. 1987. Floristic study of Morne La Visite and Pic Macaya National Parks, Haiti. Bulletin of the Florida State Museum—Biological Sciences 32 (1): 1–136.
[K15] Kellogg, E. A. 2015. The Families and Genera of Vascular Plants vol. 13. Flowering Plants: Monocots: Poaceae. Springer.
[MB08] Maiden, J. H., & E. Betche. 1908. Notes from the Botanic Gardens, Sydney. No. 13. Proceedings of the Linnean Society of New South Wales 33: 304–319.
[M83] Myers, R. L. 1983. Site susceptibility to invasion by the exotic tree Melaleuca quinquenervia in southern Florida. Journal of Applied Ecology 20: 645–658.
[M68] Munz, P. A. 1968. Supplement to a California Flora. University of California Press.
[P17] Pilger, R. 1917. Gramineae africanae. XIII. (Andropogoneae). Botanische Jahrbücher für Systematik, Pflanzengeschichte und Pflanzengeographie 54: 279–288.
[RJ11] Rising, J. D., A. Jaramillo, J. L. Copete, P. G. Ryan & S. C. Madge. 2011. Family Emberizidae (buntings and New World sparrows). In: Hoyo, J. del, A. Elliott & D. A. Christie (eds) Handbook of the Birds of the World vol. 16. Tanagers to New World Blackbirds pp. 428–683. Lynx Edicions: Barcelona.
[SY02] Salunkhe, C. B., & S. R. Yadav. 2002. Additions to the grasses of Maharashtra. Journal of the Bombay Natural History Society 99 (3): 569–573.
[S03] Singh, J. N. 2003. Grasses and their hydro-edaphic characteristics in the grassland habitat of Nilgiris Biosphere Reserve, Tamil Nadu. Bulletin of the Botanical Survey of India 45: 143–164.
[S06] Stuckert, T. 1906. Segunda contribución al conocimiento de las gramináceas Argentinas. Anales del Museo Nacional de Buenos Aires, serie 3, 6: 409–555.
[TGL-S08] Thulin, M., D. Goyder & S. Liede-Schumann. 2008. Cibirhiza spiculata (Apocynaceae), a remarkable new species from eastern Ethiopia. Kew Bulletin 63 (4): 617–624.
[WM20] Welker, C. A. D., M. R. McKain, M. C. Estep, R. S. Pasquet, G. Chipabika, B. Pallangyo & E. A. Kellogg. 2020. Phylogenomics enables biogeographic analysis and a new subtribal classification of Andropogoneae (Poaceae—Panicoideae). Journal of Systematics and Evolution 58 (6): 1003–1030.