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Digitaria ischaemum
SMOOTH CRAB GRASS

Higher Taxonomy
Family: Poaceae (Gramineae)View DescriptionDichotomous Key

Common Name: GRASS FAMILY
Habit: Annual to woody perennial herb; roots generally fibrous. Stem: generally round, hollow; nodes swollen, solid. Leaf: alternate, 2-ranked, generally linear, parallel-veined; sheath generally open; ligule membranous or hairy, at blade base. Inflorescence: various (of generally many spikelets). Spikelet: glumes generally 2; florets (lemma, palea, flower) 1--many; lemma generally membranous, sometimes glume-like; palea generally +- transparent, +- enclosed by lemma. Flower: generally bisexual, minute; perianth vestigial; stamens generally 3; stigmas generally 2, generally plumose. Fruit: grain, sometimes achene- or utricle-like.
Genera In Family: 650--900 genera; +- 10550 species: worldwide; greatest economic importance of any family (wheat, rice, maize, millet, sorghum, sugar cane, forage crops, ornamental, weeds; thatching, weaving, building materials). Note: Generally wind-pollinated. Achnatherum, Ampelodesmos, Hesperostipa, Nassella, Piptatherum, Piptochaetium, Ptilagrostis moved to Stipa; Elytrigia, Leymus, Pascopyrum, Pseudoroegneria, Taeniatherum to Elymus; Hierochloe to Anthoxanthum; Lolium, Vulpia to Festuca; Lycurus to Muhlenbergia; Monanthochloe to Distichlis; Pleuraphis to Hilaria; Rhynchelytrum to Melinis. The following taxa (in genera not included here), recorded in California from historical collections or reported in literature, are extirpated, lacking vouchers, or not considered naturalized: Acrachne racemosa (Roth) Ohwi, Allolepis texana (Vasey) Soderstr. & H.F. Decker, Amphibromus nervosus (Hook. f.) Baill., Axonopus affinis Chase, Axonopus fissifolius (Raddi) Kuhlm., Coix lacryma-jobi L., Cutandia memphitica (Spreng.) K. Richt., Dinebra retroflexa (Vahl) Panz., Eremochloa ciliaris (L.) Merr., Eustachys distichophylla (Lag.) Nees, Gaudinia fragilis (L.) P. Beauv., Miscanthus sinensis Andersson, Neyraudia arundinacea (L.) Henrard, Phyllostachys aurea Rivière & C. Rivière, Phyllostachys bambusoides Siebold & Zuccarini, Rottboellia cochinchinensis (Lour.) Clayton, Schedonnardus paniculatus (Nutt.) Branner & Coville, Schizachyrium cirratum (Hack.) Wooton & Standl., Schizachyrium scoparium (Michx.) Nash, Themeda quadrivalvis (L.) Kuntze, Thysanolaena latifolia (Hornem.) Honda, Tribolium obliterum (Hemsl.) Renvoize, Zea mays L., Zizania palustris L. var. interior (Fassett) Dore, Zoysia japonica Steud. Paspalum pubiflorum E. Fourn., Paspalum quadrifarium Lam., are now reported for southern California (J Bot Res Inst Texas 4:761--770). See Glossary p. 30 for illustrations of general family characteristics.
eFlora Treatment Author: James P. Smith, Jr., except as noted
Scientific Editor: James P. Smith, Jr., J. Travis Columbus, Dieter H. Wilken.
Genus: DigitariaView DescriptionDichotomous Key

Common Name: CRAB GRASS
Habit: Annual, perennial herb. Stem: decumbent to erect. Leaf: basal and cauline; ligule membranous, ciliate or not; blade generally flat. Inflorescence: digitate to panicle-like; 1° branches +- spike-like, spreading to ascending; spikelets generally many per branch, 2 or 3 per node, short-stalked to subsessile, on one side of axis. Spikelet: dorsally compressed, falling as 1 unit; glumes unequal, upper glume <= spikelet, appressed-hairy, clearly 3--5-veined, veins minutely ridge-like; florets 2, lower floret sterile, lemma texture like upper glume, upper floret fertile, lemma +- thin, flexible, back facing away from inflorescence axis, margin flat, tip generally obtuse, awn 0; lower palea reduced or 0, the upper +- = lemma; anthers 3.
Species In Genus: +- 200 species: warm temperate, tropics, worldwide. Etymology: (Latin: finger, from inflorescence branch arrangement) Note: Digitaria bicornis (Lam.) Roem. & Schult., collected in 1926 in Monterey Co., and Digitaria eriantha Steud., collected in Imperial Co. in 1939, are presumed extirpated.

Digitaria ischaemum (Schreb.) Muhl.
NATURALIZED
Habit: Annual. Stem: 1.5--5(7) dm; decumbent or ascending, rooting at lower nodes. Leaf: sheath 1--12.5 cm, glabrous or sparsely hairy at base of blade or occasionally on lower surface; ligule +- 1--2 mm; blade 1.5--12 cm, 2.5--5(7) mm wide, upper surface glabrous. Inflorescence: terminal and axillary (generally at least partially concealed), branches 2--8, 1.5--7 cm, axes narrowly winged; spikelets generally 3 per node, stalk 0.5--3 mm. Spikelet: +- 2--2.5 mm, +- 1 mm wide, elliptic, purple; lower glume 0 or reduced to a membranous, veinless scale or rim, upper glume 3/4 to = spikelet, membranous, 3-veined; lower lemma = spikelet length, 7-veined, puberulent, acute. Chromosomes: 2n=36.
Ecology: Disturbed areas; Elevation: < 300 m. Bioregional Distribution: NCoRO, NCoRH, s SN, GV, CCo, SCo, D; Distribution Outside California: to eastern United States; native to Europe. Flowering Time: Sep--Nov
eFlora Treatment Author: James P. Smith, Jr.
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Citation for this treatment: James P. Smith, Jr. 2016. Digitaria ischaemum, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=22954, accessed on July 23, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on July 23, 2016.


Digitaria ischaemum
click for enlargement
© 2006 Steve Matson
Digitaria ischaemum
click for enlargement
© 2006 Steve Matson
Digitaria ischaemum
click for enlargement
© 2006 Steve Matson
Digitaria ischaemum
click for enlargement
© 2006 Steve Matson
Digitaria ischaemum
click for enlargement
© 2006 Steve Matson
Digitaria ischaemum
click for enlargement
© 2006 Steve Matson

More photos of Digitaria ischaemum in CalPhotos


Geographic subdivisions for Digitaria ischaemum:
NCoRO, NCoRH, s SN, GV, CCo, SCo, D;
Markers link to CCH specimen records. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues. Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
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map of distribution 1
(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurence).

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Data provided by the participants of the Consortium of California Herbaria.
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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa.
Blue line denotes eFlora flowering time.