Hierochloë (Gmel.) R.Br.
From the Greek hieros (sacred) chloë (grass), alluding to "strewing (H. odorata) before the doors of churches on festival days".
Including Ataxia R. Br., Dimeria Raf., Disarrenum Labill., Savastana Schrank, Torresia Ruiz & Pavon
Sometimes referred to Anthoxanthum
Habit, vegetative morphology. Perennial; rhizomatous, or caespitose. Culms 7–120 cm high; herbaceous. Culm nodes glabrous. Culm internodes hollow. Young shoots extravaginal. The shoots aromatic (coumarin-scented). Leaves not basally aggregated; non-auriculate. Leaf blades linear to lanceolate; narrow; flat, or folded, or rolled; without cross venation; persistent; rolled in bud; an unfringed membrane; not truncate; 2–5.5 mm long.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets. Apomictic, or reproducing sexually.
Inflorescence. Inflorescence paniculate; open; with capillary branchlets, or without capillary branchlets. Primary inflorescence branches inserted all around the main axis. Inflorescence espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund.
Female-fertile spikelets. Spikelets 3.5–7 mm long; compressed laterally; disarticulating above the glumes; not disarticulating between the florets. Rachilla terminated by a female-fertile floret. Hairy callus absent.
Glumes two; very unequal to more or less equal; about equalling the spikelets; shorter than the adjacent lemmas, or long relative to the adjacent lemmas; pointed; awnless; carinate; similar (membranous, ovate). Lower glume 1–5 nerved. Upper glume 3–5 nerved. Spikelets with incomplete florets. The incomplete florets proximal to the female-fertile florets. Spikelets with proximal incomplete florets. The proximal incomplete florets 2; paleate; male (with 3 stamens, or rarely neuter). The proximal lemmas awned, or awnless; 5 nerved; more or less equalling the female-fertile lemmas to decidedly exceeding the female-fertile lemmas; less firm than the female-fertile lemmas (membranous); not becoming indurated.
Female-fertile florets 1. Lemmas becoming indurated (usually), or not becoming indurated (in only 1 species); entire; blunt; awnless, or mucronate, or awned. Awns when present, 1; dorsal; from near the top; non-geniculate; much shorter than the body of the lemma; entered by one vein. Lemmas hairy, or hairless; non-carinate; 3–5(–7) nerved. Palea present; relatively long; 1-nerved; keel-less (2-keeled in male florets). Lodicules present; 2; free; membranous; glabrous; toothed, or not toothed. Stamens 2 (3 in male florets). Anthers 1–3.5 mm long; not penicillate. Ovary glabrous. Styles fused, or free to their bases. Stigmas 2; white, or brown.
Fruit, embryo and seedling. Fruit free from both lemma and palea; small; compressed laterally. Hilum short. Embryo small; not waisted. Endosperm hard; with lipid; containing compound starch grains. Embryo with an epiblast; without a scutellar tail; with a negligible mesocotyl internode. Embryonic leaf margins meeting.
First seedling leaf with a well-developed lamina. The lamina narrow; 3–5 veined.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells similar in shape costally and intercostally; differing markedly in wall thickness costally and intercostally (the costals thicker). Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs absent. Stomata common, or absent or very rare. Subsidiaries low dome-shaped, or parallel-sided. Intercostal short-cells common, or absent or very rare. Costal short-cells conspicuously in long rows (rarely), or neither distinctly grouped into long rows nor predominantly paired. Costal silica bodies horizontally-elongated crenate/sinuous, or horizontally-elongated smooth.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma. Leaf blade ‘nodular’ in section; with the ribs more or less constant in size. Midrib conspicuous, or not readily distinguishable; with one bundle only, or having a conventional arc of bundles. Bulliforms present in discrete, regular adaxial groups (in the furrows); in simple fans (and sometimes in ill-defined groups of small cells, cf. Ammophila). All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; forming ‘figures’, or nowhere forming ‘figures’. Sclerenchyma all associated with vascular bundles.
Phytochemistry. Leaves without flavonoid sulphates (1 species).
Cytology. Chromosome base number, x = 7. 2n = 14, 28, 42, 56, 64, 66, 68, 71, and 72, or 74–78. 2, 4, 6, 8, 9, 10, and 11 ploid (and aneuploids). Chromosomes ‘large’.
Taxonomy. Pooideae; Poodae; Aveneae.
Distribution, ecology, phytogeography. 30 species; temperate & cold regions. Helophytic to mesophytic; shade species and species of open habitats. Woods, marshes, grasslands, tundra.
Holarctic, Paleotropical, Neotropical, Australian, and Antarctic. Boreal, Tethyan, and Madrean. Indomalesian. Arctic and Subarctic, Euro-Siberian, Eastern Asian, Atlantic North American, and Rocky Mountains. Mediterranean and Irano-Turanian. Indo-Chinese, Malesian, and Papuan. Caribbean and Andean. North and East Australian. New Zealand and Patagonian. European and Siberian. Canadian-Appalachian. Temperate and South-Eastern Australian.
Rusts and smuts. Rusts — Puccinia. Taxonomically wide-ranging species: Puccinia graminis, Puccinia coronata, Puccinia praegracilis, and Puccinia recondita. Smuts from Tilletiaceae and from Ustilaginaceae. Tilletiaceae — Urocystis. Ustilaginaceae — Ustilago.
References, etc. Morphological/taxonomic: Schouten and Veldkamp 1985. Leaf anatomical: Metcalfe 1960; this project.
Illustrations. • Inflorescence detail. Hierochloe redolens. • Spikelet. Hierochloe redolens. Two proximal incomplete florets with short-awned lemmas. • Spikelets. Hierochloe rariflora. • Spikelet. Hierochloe rariflora. • Abaxial epidermis of leaf blade. Hierochloe rariflora
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).
