Ehrharta sens. lat.
Named after Friedrich Ehrhart, a Swiss botanist.
Including Diplax Bennett, Trochera L. Rich., Microlaena, Petriella, Tetrarrhena
Habit, vegetative morphology. Annual, or perennial; not reeds; rhizomatous, or stoloniferous, or caespitose, or decumbent. Culms 1–71.16–200 cm high; woody and persistent, or herbaceous; scandent, or not scandent (wiry, often long and scrambling); branched above, or unbranched above; tuberous, or not tuberous. Culm nodes hairy, or glabrous. Culm internodes solid, or hollow. Plants unarmed; without multicellular glands. Young shoots extravaginal, or intravaginal. The shoots not aromatic. Leaves mostly basal, or not basally aggregated; clearly differentiated into sheath and blade; distichous; auriculate, or non-auriculate; without auricular setae. Sheath margins free. Leaf blades not all greatly reduced; linear, or linear-lanceolate, or lanceolate, or ovate-lanceolate; neither leathery nor flimsy; broad, or narrow; 0.5–12 mm wide; not cordate, not sagittate; setaceous, or not setaceous; flat (or concave), or folded, or rolled; not needle-like; not pseudopetiolate; parallel veined; cross veined, or without cross venation; disarticulating from the sheaths, or persistent; rolled in bud; ligule present; an unfringed membrane, or a fringed membrane, or a fringe of hairs; truncate, or not truncate; 0.5–3 mm long. Contra-ligule absent.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets. The spikelets all alike in sexuality (but sometimes cleistogamous, leading to reduced paleas and lodicules, and indehiscent stamens); hermaphrodite. Plants outbreeding, or inbreeding; exposed-cleistogamous, or chasmogamous; with hidden cleistogenes, or without hidden cleistogenes. The hidden cleistogenes when present, in the leaf sheaths. Reproducing sexually.
Inflorescence. Inflorescence determinate; without pseudospikelets; few spikeleted, or many spikeleted; a single raceme (spike-like, the axis flexuous), or paniculate (then narrow,with slender branches); not deciduous; open, or contracted; without conspicuously divaricate branchlets; with capillary branchlets, or without capillary branchlets; non-digitate. Inflorescence with axes ending in spikelets. Rachides neither flattened nor hollowed, not winged. Inflorescence espatheate (though in two species (Ehrhatra sens str.) the mature inflorescence base is enclosed in the uppermost leaf sheath); not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets unaccompanied by bractiform involucres, not associated with setiform vestigial branches; solitary; secund, or not secund; subsessile, or pedicellate; imbricate, or not imbricate; not in distinct ‘long-and-short’ combinations.
Female-fertile spikelets. Spikelets morphologically ‘conventional’; 2–17 mm long; compressed laterally, or not noticeably compressed; disarticulating above the glumes; not disarticulating between the florets; with conventional internode spacings, or with a distinctly elongated rachilla internode above the glumes (i.e., beneath the empty lemmas). Rachilla inconspicuously prolonged beyond the uppermost female-fertile floret, or terminated by a female-fertile floret; hairy, or hairless; the rachilla extension when present, naked. Hairy callus present, or absent. Callus absent.
Glumes present; two; minute, or relatively large; very unequal (the G2 longer), or more or less equal; shorter than the spikelets, or about equalling the spikelets, or exceeding the spikelets; shorter than the adjacent lemmas, or long relative to the adjacent lemmas; free; not ventricose; hairless; glabrous, or scabrous; without conspicuous tufts or rows of hairs; pointed, or not pointed (blunt to truncate); awnless; carinate, or non-carinate; without a median keel-wing; very dissimilar, or similar (membranous to leathery). Lower glume 0.5–1 times the length of the upper glume; shorter than the lowest lemma; much shorter than half length of lowest lemma; not two-keeled; 0–3 nerved, or 5 nerved. Upper glume not saccate; 0–1 nerved, or 3–5 nerved; not prickly. Spikelets with incomplete florets. The incomplete florets proximal to the female-fertile florets. The proximal incomplete florets 2; epaleate; sterile. The proximal lemmas curiously varied in form, often hardened and transversely ridged, the lower sometimes bearing a knob-like appendage (elaieosome?) at its base; awned (abruptly from the back, or the lemma tapering into the awn), or awnless; 0–9 nerved; exceeded by the female-fertile lemmas, or more or less equalling the female-fertile lemmas, or decidedly exceeding the female-fertile lemmas; less firm than the female-fertile lemmas, or similar in texture to the female-fertile lemmas, or decidedly firmer than the female-fertile lemmas; becoming indurated, or not becoming indurated.
Female-fertile florets 1. Lemmas not conspicuously non-distichous; not convolute; not saccate; without a crown; similar in texture to the glumes, or decidedly firmer than the glumes; usually smooth (and often polished), or striate; becoming indurated, or not becoming indurated; entire; pointed, or blunt (truncate); not crested; awnless (usually), or mucronate (occasionally), or awned (tapered into the stout awn). Awns not of the triple/trifid, basal column type (1/1); (when present) 1; median; apical; not hooked; non-geniculate; hairless; much shorter than the body of the lemma. Lemmas rarely sparsely hairy, or hairless. The hairs not in tufts; not in transverse rows. Lemmas usually glabrous, or scabrous; carinate, or non-carinate. The keel wingless. Lemmas without a germination flap; 1–7 nerved; with the nerves non-confluent. Palea present; relatively long (narrow), or conspicuous but relatively short, or very reduced; not convolute; entire; awnless, without apical setae; thinner than the lemma; not indurated; nerveless (rarely), or 1-nerved, or 2-nerved, or several nerved; keel-less, or one-keeled (by apposition of the two), or 2-keeled. Palea keels wingless. Lodicules present; 2; free; membranous; ciliate, or glabrous; toothed (two toothed or irregularly serrate), or not toothed; rather heavily vascularized (Tateoka 1967). Stamens 2–6; with free filaments. Anthers 1–3 mm long; not penicillate; without an apically prolonged connective. Ovary glabrous; without a conspicuous apical appendage. Styles fused to free to their bases. Stigmas 2; white, or brown.
Fruit, embryo and seedling. Fruit free from both lemma and palea; small, or medium sized; oblong-linear or ellipsoid; not grooved; compressed laterally; smooth. Hilum short, or long-linear. Pericarp thin; fused. Embryo small; waisted, or not waisted. Seed endospermic. Endosperm hard; without lipid; containing compound starch grains. Embryo with an epiblast, or without an epiblast; with a scutellar tail; with an elongated mesocotyl internode, or with a negligible mesocotyl internode. Embryonic leaf margins overlapping.
Seedling with a short mesocotyl, or with a long mesocotyl; with a tight coleoptile. First seedling leaf with a well-developed lamina. The lamina broad, or narrow; erect, or curved; 5–12 veined.
Ovule, embryology. Outer integument extensive, being absent only from the micropylar region; two cells thick at the micropylar margin. Inner integument continuous, the micropyle constricted; thickened around the micropyle. Synergids not haustorial; without large, globular starch grains.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells similar in shape costally and intercostally; of similar wall thickness costally and intercostally. Intercostal zones with typical long-cells. Mid-intercostal long-cells rectangular, or fusiform; having markedly sinuous walls, or having straight or only gently undulating walls. Microhairs present, or absent; panicoid-type; 30–63 microns long; 4.5–18 microns wide at the septum. Microhair total length/width at septum 2.1–10. Microhair apical cells 10.5–27.41–49 microns long. Microhair apical cell/total length ratio 0.31–0.565–0.71. Stomata common (2/3), or absent or very rare (1/3); 21–30.91–49 microns long. Subsidiaries dome-shaped (3/3), or triangular (2/3); not including both parallel-sided and triangular forms on the same leaf (3/3). Guard-cells overlapped by the interstomatals (1/3), or overlapping to flush with the interstomatals (2/3). Intercostal short-cells common (3/3), or absent or very rare (2/3); in cork/silica-cell pairs (1/2), or not paired (1/2); silicified (2/3), or not silicified (2/3). Intercostal silica bodies rounded (2/2), or crescentic (2/2), or tall-and-narrow (1/2). Crown cells absent (3/3). Costal zones with short-cells (3/3). Costal short-cells conspicuously in long rows (3/3), or predominantly paired (1/3), or neither distinctly grouped into long rows nor predominantly paired (1/3). Costal silica bodies rounded (2/3), or saddle shaped (1/3), or crescentic (1/3), or ‘panicoid-type’ (3/3); cross shaped (2/2), or butterfly shaped (2/2), or dumb-bell shaped (2/2); not sharp-pointed (3/3).
Transverse section of leaf blade, physiology. Leaf blades ‘laminar’.
C3 (3/3); XyMS+ (3/3). PBS cells without a suberised lamella (1/1). Mesophyll with radiate chlorenchyma (1/3), or with non-radiate chlorenchyma (3/3); without adaxial palisade (3/3); not Isachne-type (3/3); without ‘circular cells’ (3/3); traversed by columns of colourless mesophyll cells (1/3), or not traversed by colourless columns (3/3); with arm cells (1/3), or without arm cells (3/3); without fusoids (3/3). Leaf blade with distinct, prominent adaxial ribs (2/3), or ‘nodular’ in section (2/3), or adaxially flat (2/3); with the ribs more or less constant in size (3/3), or with the ribs very irregular in sizes (1/3). Midrib conspicuous (2/3), or not readily distinguishable (2/3); with one bundle only (3/3); with colourless mesophyll adaxially (1/3), or without colourless mesophyll adaxially (3/3). Bulliforms present in discrete, regular adaxial groups (3/3); in simple fans (3/3); nowhere involved in bulliform-plus-colourless mesophyll arches (3/3). All the vascular bundles accompanied by sclerenchyma (3/3). Combined sclerenchyma girders present (3/3); forming ‘figures’ (2/2), or nowhere forming ‘figures’ (1/2). Sclerenchyma all associated with vascular bundles (3/3).
Culm anatomy. Culm internode bundles in one or two rings (1/1).
Phytochemistry. Tissues of the culm bases with abundant starch (2/2), or with little or no starch (1/2). Leaves containing flavonoid sulphates (1/2), or without flavonoid sulphates (1/2).
Special diagnostic feature. Spikelets not borne as in ‘Anadelphia scyphofera’ (q.v.). Plant not as in Anomochloa (q.v.). The inflorescences not as in Atractantha (q.v.). Lemmas not as in Briza (q.v.). Lemma not wing-awned. Inflorescence not as in Buchloë (q.v.). Upper glume not as in Centrochloa (q.v.). Inflorescences not as in Coix (q.v.). Spikelets not borne as in Cornucopiae (q.v.). Lemmas without the characteristic Corynephorus awn. Plants not as in Cyperochloa (q.v.). Fruit not as in Diarrhena (q.v.). Plants not as in Dichanthelium (q.v.). No Eriochloa-type ‘callus’. Plants not as in Hubbardia (q.v.). The adaxial surface of the leaf blade not as in Hydrothauma (q.v.). Plants not as in Hygroryza (q.v.). Not having female spikelets as in Leptaspis and Scrotochloa (q.v.). Female-fertile lemma not as in Lombardochloa (q.v.). Spikelets not as in Lopholepis (q.v.). Plant and inflorescence not as in Lygeum (q.v.). Spikelets not arranged as in Manisuris (q.v.). Spikelets without a terminal clavate appendage. Spikelet not as in Nassella (q.v.). The inflorescence not as in Odontelytrum (q.v.). The lower lemma not resembling a Bothriochloa pedicel in appearance, and without a pair of hygroscopically active setae. Seed not as in Phaenosperma (q.v.). Spikelets not borne on a broad, leaflike rachis. Not scandent as in Prosphytochloa (q.v.). Female-fertile lemma not as in Rhynchoryza (q.v.). Not rush-like. Inflorescence not as in Spinifex (q.v.). Plants not as in Steyermarkochloa (q.v.). Flowering culms not as in Thuarea (q.v.). Lower glume without a Thyridolepis-type window (q.v.). The inflorescence not as in Viguierella (q.v.). Fruiting inflorescence not as in maize (q.v.). Plants not as in Zygochloa (q.v.).
Cytology. Chromosome base number, x = 10 (1/2), or 12 (1/2). 2n = 24 and 48. 2 and 4 ploid (1/1).
Taxonomy. Bambusoideae; Oryzodae; Ehrharteae. Veldtgrasses.
Distribution, ecology, phytogeography. 37 species; southern and tropical Africa, Mascarene Is., New Zealand, Philippines, Java to Australasia. Commonly adventive, or not commonly adventive. Helophytic (most of the annuals), or mesophytic; shade species, or species of open habitats; halophytic, or glycophytic. Diverse habitats, with E. villosa in coastal sand dunes.
Paleotropical, Cape, Australian, and Antarctic. African, Indomalesian, and Polynesian. Saharo-Sindian, Sudano-Angolan, and Namib-Karoo. Indian, Malesian, Papuan. Hawaiian, Fijian. North and East Australian, South-West Australian. New Zealand. Sahelo-Sudanian, Somalo-Ethiopian, and South Tropical African. Tropical North and East Australian, Temperate and South-Eastern Australian.
Rusts and smuts. Rusts — Puccinia, or no rusts recorded. Taxonomically wide-ranging species: no wide-ranging rust species. Smuts from Tilletiaceae and from Ustilaginaceae, or not recorded. Tilletiaceae — Tilletia. Ustilaginaceae — Ustilago.
Economic importance. Significant weed species: E. brevifolia, E. calycina, E. dura, E. erecta, E. longiflora, E. villosa. Cultivated fodder: E. erecta, E. calycina. Important native pasture species: E. erecta.
References, etc. Morphological/taxonomic: Willemse 1982; Gibbs Russell and Ellis 1987, 1988; Gibbs Russell 1987. Leaf anatomical: Ellis 1987 and this project.
Special comments. Anatomical data more or less satisfactory, or wanting.
Cite this publication as: Watson, L., and Dallwitz, M. J. (1992 onwards). ‘Grass Genera of the World: Descriptions, Illustrations, Identification, and Information Retrieval; including Synonyms, Morphology, Anatomy, Physiology, Phytochemistry, Cytology, Classification, Pathogens, World and Local Distribution, and References.’ http://biodiversity.uno.edu/delta/. Version: 18th August 1999. Dallwitz (1980), Dallwitz, Paine and Zurcher (1993 onwards, 1998), and Watson and Dallwitz (1994), and Watson, Dallwitz, and Johnston (1986) should also be cited (see References).