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Key to families | Table of families and genera

Specimen numbers are hyperlinked to records in the Consortium of California Herbaria data view where possible. Taxa are hyperlinked to entries in the Jepson Interchange via the "[Online Interchange]" link.

 

PANICUM PANIC GRASS

Robert W. Freckmann & Robert Webster


Annual, perennial herb. Stem: generally erect or ascending; internode solid to hollow. Leaf: basal and cauline, similar or dissimilar, basal rosette well developed or not; blade generally flat or rolled under; sheath glabrous or hairy; ligule short-hairy or membranous, ciliate, hairs generally > membrane, with an adjacent false ligule of longer hairs in some species Inflorescence: panicle-like, generally open; 1° branches spreading to ascending; 2° main branches simple or forked at base; spikelets many, 1–2 per node, generally stalked, on one side of axis or not, stalk tip expanded, one side concave. Spikelet: falling as 1 unit, ± compressed, generally green to ± purple; glumes generally unequal, lower generally < upper, free, clasping, upper glume ± = spikelet, membranous, ± thin; florets 2, lower sterile or staminate, lemma texture like glumes, upper floret fertile, lemma leathery to hard, firm, generally shiny, smooth to rough, margin inrolled or partly flat, tip blunt, palea ± enclosed by lemma margin.
± 440 species: tropics to warm temperate, worldwide. (Latin: ancient name for millet) [Freckmann & Lelong 2003 FNANM 25:406–450, 450–488] Subg. Dichanthelium often recognized as distinct, monophyletic genus, as in FNANM by Freckmann; based on editorial decision, Panicum treated here to include Dichanthelium, which is phylogenetically nested in Panicum.

Key to Panicum

1. Leaves in 2 forms, basal < and generally wider than cauline, rosette well developed, generally persistent; main panicle branches forked at base (subg. Dichanthelium)

2. Spikelet 2.7–3.5 mm, 2–2.4 mm wide; upper glume 9-veined with a prominent orange spot at base, lower glume acuminate; ligule hairs 1–1.5 mm ..... P. oligosanthes var. scribnerianum

2' Spikelet 1–2 mm, ± < 1 mm wide; upper glume 7-veined, lacking orange spot at base, lower glume acute; ligule of hairs 2–4 mm ..... P. acuminatum

3. Stem, lower sheath generally glabrous ..... var. lindheimeri

3' Stem, sheath soft-hairy

4. Leaf blade puberulent abaxially; inflorescence generally long-exserted ..... var. fasciculatum

4' Leaf blade soft-hairy abaxially; inflorescence generally scarcely exserted ..... var. thermale

1' Leaves gradually reduced upward, basal rosette not well developed; main panicle branches simple at base (subg. Panicum)

5. Sheath compressed-keeled, blade folded at base; ligule ragged ..... P. rigidulum subsp. rigidulum

5' Sheath not compressed-keeled, blade flat or rolled under; ligule ciliate

6. Perennial herb, generally with rhizomes or stolons; lower floret staminate

7. Stem hard, almost woody; upper lemma with flat margin ..... P. antidotale

7' Stem not especially hard; upper lemma margin inrolled ..... P. urvilleanum

6' Annual; lower floret sterile

8. Stem, leaves ± glabrous; lower glume ± truncate, < 1/3 spikelet length ..... P. dichotomiflorum subsp. dichotomiflorum

8' Stem, leaves hairy; lower glume acute, > 1/3 spikelet length

9. Spikelet > 4 mm; panicle dense, spikelets in overlapping clusters ..... P. miliaceum subsp. miliaceum

9' Spikelet < 4 mm; panicle open, most spikelets well separated

10. Lower palea 0; base of upper floret without paired crescent-shaped scars ..... P. capillare

10' Lower palea present; base of upper floret generally with paired crescent-shaped scars

11. Spikelet axis not elongated between glumes and florets; lower glume 1–1.5 mm, < 1/2 spikelet length; stalks generally spreading, generally > 2 mm ..... P. hillmanii

11' Spikelet axis ± elongated between glumes and florets, visible; lower glume 1.5–2.5 mm, > 1/2 spikelet length; stalks generally appressed, generally < 2 mm ..... P. hirticaule subsp. hirticaule

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Citation for the whole project: Jepson Flora Project (eds.) [year] Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html [accessed on month, day, year]
Citation for an individual treatment: [Author of taxon treatment] [year]. [Taxon name] in Jepson Flora Project (eds.) Jepson eFlora, [URL for treatment]. Accessed on [month, day, year].
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