Ehrhartoideae

Belongs within: Poaceae.
Contains: Oryzeae.

The Ehrhartoideae are a clade of grasses supported primarily by molecular data, characterised by the presence of one female-fertile floret per spikelet. Many members of the subfamily are found in moist habitats, and this may be the ancestral environment for the clade (Kellogg 2015).

Within the ehrhartoids, members of the African tribe Phyllorachideae have the inflorescence axis broad, flattened, and leaf-like, enclosing the primary branches and spikelets. Phyllorachis sagittata bears staminate and pistillate spikelets on the same inflorescence branch whereas Humbertochloa species have staminate and pistillate spikelets in separate inflorescences. In the genus Ehrharta, spikelets contain two well developed glumes, two sterile lemmas and one bisexual flower (Kellogg 2015). The genus Microlaena has historically been recognised for species with very small glumes, but has been established to be polyphyletic within Ehrharta. The drought-tolerant weeping grass Ehrharta stipoides is used as a pasture grass and has been investigated as a grain crop.

Characters (Kellogg 2015): Rhizomatous, stoloniferous, or caespitose perennials, herbaceous or with a woody caudex. Ligule membranous, a fringed membrane, or a fringe of hairs. Inflorescences branched or unbranched, spikelets pedicellate. Spikelets with glumes 0 or 2, with two proximal flowers sterile and often reduced, only distal flower fertile. Flowers bisexual or unisexual. Lemma with or without an awn. Lodicules 2. Caryopsis with hard endosperm, with a long-linear hilum, embryo with an epiblast, with a scutellar cleft, without a mesocotyl internode, with embryonic leaf margins overlapping. Fusoid cells absent or present, mesophyll cells with or without invaginated cell walls, midrib simple or complex. Silica bodies in leaves transverse to proximo-distal axis. Photosynthetic pathway C₃.

<==Ehrhartoideae [Oryzoideae]
    |  i. s.: Suddia Renvoize 1984K15
    |           `--S. sagittifoliaK15
    |--PhyllorachideaeK15
    |    |--Phyllorachis Trimen. 1879K15
    |    |    `--P. sagittataK15
    |    `--Humbertochloa Camus & Stapf 1934K15
    |         `--H. greenwayiiK15
    `--+--OryzeaeK15
       `--Ehrharta Thunb. 1779 (see below for synonymy)K15
            |--E. acuminata [=Tetrarrhena acuminata]B78
            |--E. avenaceaK15
            |--E. brevifoliaB78
            |    |--E. b. var. brevifoliaG52
            |    `--E. b. var. cuspidataG52
            |--E. bulbosaGPWG01
            |--E. calycinaGPWG01
            |--E. capensisK15
            |--E. colensoiC06 [=Microlaena colensoiA27, Zotovia colensoiK15]
            |--E. delicatulaK15
            |--E. diplaxK15 [incl. Diplax avenaceaC06, Microlaena avenaceaK15]
            |--E. distichophylla [=T. distichophylla]B78
            |--E. duraGPWG01
            |--E. erectaB00
            |--E. juncea [=Tetrarrhena juncea; incl. E. contexta, E. tenuissima, Tetrarrhena tenuissima]B78
            |    |--D. j. var. junceaB78
            |    `--‘Tetrarrhena’ j. var. scabra [incl. Ehrharta uniglumis]B78
            |--E. laevis [=Tetrarrhena laevis Br. 1810; incl. T. drummondii]G52
            |--E. longifloraB00
            |--E. multinodaK15
            |--E. paniceaC55
            |--‘Microlaena’ polynoda [=Diplax polynoda; incl. M. ramosissima col. 1889]C06
            |--E. pusillaG52
            |--E. stipoidesG52 [=Microlaena stipoides (Labill.) Br. 1810G52; incl. M. gunniiB78]
            |--E. tasmanicaK15 [=Diplax tasmanicaB78, Microlaena tasmanicaK15; incl. Ehrharta diarrhenaB78]
            |    |--E. t. var. tasmanicaB78
            |    `--‘Microlaena’ t. var. subalpinaB78
            |--E. thomsoni Petrie 1880C06 [=Microlaena thomsoniA27, Zotovia thomsoniiK15]
            |--E. triandraK15
            `--E. villosaG52
                 |--E. v. var. villosaG52
                 `--E. v. var. maximaG52

Ehrharta Thunb. 1779 [incl. Microlaena Br. 1810, Petriella Zotov 1943 non Curzi 1930, Tetrarrhena Br. 1810, Zotovia Edgar & Connor 1998; Ehrharteae]^K15

*Type species of generic name indicated

References

[A27] Andersen, J. C. 1927. Popular names of New Zealand plants. Part 2. Transactions and Proceedings of the New Zealand Institute 57: 905–977.

[B78] Bentham, G. 1878. Flora Australiensis: A description of the plants of the Australian Territory vol. 7. Roxburghiaceae to Filices. L. Reeve & Co.: London.

[B00] Braby, M. F. 2000. Butterflies of Australia: their identification, biology and distribution vol. 1. CSIRO Publishing: Collingwood (Victoria).

[C55] Candolle, A. de. 1855. Géographie Botanique Raisonée: Ou exposition des faits principaux et des lois concernant la distribution géographique des plantes de l’époque actuelle vol. 2. Librairie de Victor Masson: Paris.

[C06] Cheeseman, T. F. 1906. Manual of the New Zealand Flora. John Mackay, Government Printer: Wellington.

[G52] Gardner, C. A. 1952. Flora of Western Australia vol. 1 pt 1. Gramineae. William H. Wyatt: Perth.

[GPWG01] Grass Phylogeny Working Group. 2001. Phylogeny and subfamilial classification of the grasses (Poaceae). Annals of the Missouri Botanical Garden 88 (3): 373–457.

[K15] Kellogg, E. A. 2015. The Families and Genera of Vascular Plants vol. 13. Flowering Plants: Monocots: Poaceae. Springer.