Sieglingia Bernh.
Named for a botanist, Siegling.
Sometimes referred to Danthonia
Habit, vegetative morphology. Perennial; caespitose. Culms 10–60 cm high; herbaceous; tuberous, or not tuberous. Culm nodes glabrous. Culm internodes hollow. Leaves mostly basal; non-auriculate. Leaf blades narrow; flat, or rolled; without cross venation; persistent; rolled in bud, or once-folded in bud; a fringe of hairs. Contra-ligule present (of hairs).
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets; inbreeding; exposed-cleistogamous, or chasmogamous; with hidden cleistogenes, or without hidden cleistogenes. The hidden cleistogenes (when present) in the leaf sheaths (sometimes basal and very modified).
Inflorescence. Inflorescence few spikeleted; a single raceme, or paniculate; open, or contracted; espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets secund, or not secund; pedicellate.
Female-fertile spikelets. Spikelets 6–12(–14) mm long; compressed laterally; disarticulating above the glumes; disarticulating between the florets; with conventional internode spacings. Rachilla prolonged beyond the uppermost female-fertile floret; hairless; the rachilla extension with incomplete florets. Hairy callus present.
Glumes two; more or less equal; about equalling the spikelets; long relative to the adjacent lemmas; pointed, or not pointed; awnless; similar (rounded below, keeled above, lanceolate to ovate). Lower glume 3–5 nerved. Upper glume 3–5 nerved. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets.
Female-fertile florets 4–6. Lemmas similar in texture to the glumes to decidedly firmer than the glumes; not becoming indurated; incised; not deeply cleft; mucronate (via the central tooth); hairy (short-haired on the lower margins), or hairless. The hairs not in tufts; not in transverse rows. Lemmas non-carinate; 7–9 nerved. Palea present; relatively long; entire; awnless, without apical setae; 2-nerved; 2-keeled. Palea keels wingless (but each enlarging and progressively thickening towards the base - by contrast with Danthonia s. str.?). Lodicules present; fleshy; glabrous. Stamens 3. Anthers 0.2–0.4 mm long; not penicillate. Ovary glabrous. Styles free to their bases. Stigmas 2.
Fruit, embryo and seedling. Fruit free from both lemma and palea; small; longitudinally grooved. Hilum long-linear. Embryo large (compared with Danthonia sensu stricto); waisted. Endosperm hard; without lipid. Embryo without an epiblast; with a scutellar tail; with an elongated mesocotyl internode. Embryonic leaf margins overlapping.
Seedling with a long mesocotyl; with a loose coleoptile. First seedling leaf with a well-developed lamina. The lamina narrow; 5 veined.
Ovule, embryology. Outer integument covering no more than the chalazal half of the ovule. Inner integument discontinuous distally. Synergids haustorial.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells markedly different in shape costally and intercostally (the costals narrower); of similar wall thickness costally and intercostally (rather thick walled, and heavily pitted anticlinally and on the surface). Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs present; panicoid-type (large); (78–)81–99(–102) microns long; (12–)12.6–15(–18) microns wide at the septum. Microhair total length/width at septum 4.3–7.9. Microhair apical cells (36–)40.5–46.5(–52.5) microns long. Microhair apical cell/total length ratio 0.44–0.52. Stomata absent or very rare (scarce in material seen), or common (see Metcalfe); 31–34 microns long. Subsidiaries dome-shaped and triangular (of the truncated type, in the material seen). Guard-cells overlapped by the interstomatals (very slightly), or overlapping to flush with the interstomatals. Intercostal short-cells common; in cork/silica-cell pairs (and solitary); silicified. Intercostal silica bodies mostly tall-and-narrow, or crescentic (a few cubical or saddle-shaped). Costal short-cells conspicuously in long rows. Costal silica bodies ‘panicoid-type’; short dumb-bell shaped, or cross shaped; not sharp-pointed.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma; without adaxial palisade; without ‘circular cells’ (but often with a region of translucent, spongy tissue in the mid-interveinal regions of the mesophyll). Leaf blade with distinct, prominent adaxial ribs to adaxially flat (the adaxial ribs very slight); with the ribs more or less constant in size. Midrib conspicuous (by virtue of the large associated hinge groups); with one bundle only. Bulliforms present in discrete, regular adaxial groups (these conspicuous, in all the slight furrows); in simple fans. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; forming ‘figures’ (the midrib with an anchor, the rest of the bundles with I’s). Sclerenchyma all associated with vascular bundles.
Cytology. Chromosome base number, x = 6, or 9 (?). 2n = 24, 36, and 124. 3, 4, and 14 ploid. Chromosomes ‘fairly small’.
Taxonomy. Arundinoideae; Danthonieae.
Distribution, ecology, phytogeography. 1 species; Madeira, Algeria, Europe, Asia Minor. Commonly adventive.
Holarctic. Boreal and Tethyan. Euro-Siberian. Mediterranean and Irano-Turanian.
Hybrids. Intergeneric hybrids with Danthonia (×Danthosieglingia Domin).
Rusts and smuts. Rusts — Puccinia. Taxonomically wide-ranging species: Puccinia brachypodii.
References, etc. Leaf anatomical: Metcalfe 1960; this project.
Illustrations. • Abaxial epidermis of leaf blade
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).
