Panicum L.

First published in Sp. Pl.: 55 (1753)
This genus is accepted
The native range of this genus is Cosmopolitan.

Descriptions

Gramineae, W. D. Clayton, S. M. Phillips And S. A. Renvoize. Flora of Tropical East Africa. 1974

Morphology General Habit
Annuals or perennials
Morphology Leaves
Leaf-blades rolled or flat, linear to ovate; ligule a short ciliate membranous rim
Morphology Reproductive morphology Inflorescences
Inflorescence a panicle, usually much branched but occasionally contracted about the primary branches
Morphology Reproductive morphology Inflorescences Spikelets
Spikelets usually spherical, ovate or oblong; glumes hyaline to membranous, usually the lower shorter than, and the upper as long as the spikelet; lower floret ♂ or barren, its lemma usually resembling the upper glume, with or without a palea; upper lemma ± as long as the spikelet, crustaceous, not crested, the margins inrolled and clasping only the edges of the palea
Morphology Reproductive morphology Fruits
Caryopsis ± ellipsoid, dorsally compressed.
[FTEA]

M. Thulin et al. Flora of Somalia, Vol. 1-4 [updated 2008] https://plants.jstor.org/collection/FLOS

Morphology General Habit
Annual or perennial; leaves flat or inrolled, linear to ovate
Morphology Reproductive morphology Inflorescences
Inflorescence a panicle, usually much-branched but occasionally contracted about the primary branches
Morphology Reproductive morphology Inflorescences Spikelets
Spikelets dorsally or weakly laterally compressed, ovate to oblong; glumes hyaline to membranous, usually the lower shorter than, and the upper as long as the spikelet; lower floret male or barren, its lemma usually resembling the upper glume, with or without a palea; upper lemma about as long as the spikelet, crustaceous, the margins inrolled and clasping only the edges of the palea
Morphology Reproductive morphology Fruits
Caryopsis ellipsoid, dorsally compressed.
Distribution
About 280 species throughout the tropics, extending into temperate North America.
[FSOM]

Gramineae, W. D. Clayton. Flora Zambesiaca 10:3. 1989

Morphology Reproductive morphology Inflorescences Spikelets
Spikelets spherical, ovate, lanceolate or oblong.
Morphology Reproductive morphology Inflorescences Bracts Glume
Glumes hyaline to membranous, usually the inferior shorter than and the superior as long as the spikelet.
Morphology Reproductive morphology Flowers Florets
Inferior floret male or barren, its lemma usually resembling the superior glume, with or without a palea.
Morphology Reproductive morphology Inflorescences Bracts Lemma
Superior lemma as long as or shorter than the spikelet, crustaceous, the margins involute and clasping only the edges of the palea.
Morphology Reproductive morphology Fruits
Caryopsis more or less ellipsoid, dorsally compressed.
Morphology General Habit
Annuals or perennials.
Morphology Leaves Leaf lamina
Leaf laminae involute or flat, linear to ovate.
Morphology Reproductive morphology Inflorescences
Inflorescence a panicle, usually much branched but occasionally contracted about the primary branches.
[FZ]

George R. Proctor (2012). Flora of the Cayman Isands (Second Edition). Royal Botanic Gardens, Kew

Morphology General Habit
Annuals or perennials of various habit. Inflorescence paniculate, rarely racemose; spikelets more or less compressed dorsiventrally; glumes herbaceous, nerved, usually very unequal, the first often minute, the second typically equal in length to the sterile lemma, the latter of the same texture and simulating a third glume, bearing in its axil a membranous or hyaline palea and sometimes a staminate flower, or rarely the palea lacking; fertile lemma chartaceous-indurate, typically obtuse, the nerves obsolete, the margins inrolled over an enclosed palea of the same texture.
Distribution
A large genus of about 500 species, widely distributed in tropical and warm-temperate regions.
[Cayman]

nonem

Morphology General Habit
Annual (132), or perennial (340). Rhizomes absent (395), or short (42), or elongated (27). Stolons absent (452), or present (15). Culms erect (201/365), or geniculately ascending (103/365), or decumbent (93/365), or prostrate (12/365), or rambling (48/365), or arching (1/365), or leaning (4/365), or scandent (4/365); reed-like (1/112), or robust (25/112), or of moderate stature (2/112), or slender (74/112), or weak (14/112); 1-77.45-1550 cm long; spongy (5), or compressible (5), or firm (418), or wiry (30), or woody (7); without nodal roots (17/100), or with prop roots (2/100), or rooting from lower nodes (98/100). Culm-internodes similar in length (1/5), or shorter and closely spaced at top of culm (1/5), or unequal, the upper longer (1/5), or unequal, the lower longer (1/5), or alternately elongated and bunched (1/5); terete (27/42), or channelled (2/42), or elliptical in section (15/42). Culm-nodes constricted (23/30), or flush with internodes (1/30), or swollen (6/30). Lateral branches lacking (57/209), or sparse (53/209), or ample (110/209), or fastigiate (9/209), or suffrutescent (4/209). Leaves differentiated into sheath and blade (450), or without demarcation between sheath and blade (12), or with sheath almost obsolete (1). Leaf-sheath auricles absent (458), or erect (6). Ligule an eciliate membrane (58), or a ciliolate membrane (72), or a ciliate membrane (253), or a fringe of hairs (68), or absent (23). Leaf-blade base without a false petiole (449), or with a brief petiole-like connection to sheath (12), or with a false petiole (3). Leaf-blades persistent (459), or deciduous at the ligule (5); aciculate (3), or filiform (12), or linear (284), or lanceolate (215), or elliptic (5), or oblong (8), or ovate (25), or triangular (1); membranous (16), or herbaceous (435), or coriaceous (13); stiff (49), or firm (406), or flaccid (10). Leaf-blade midrib indistinct (9/33), or evident (6/33), or conspicuous (16/33), or widened (2/33). Leaf-blade venation without cross veins (444), or with obscure cross veins (6), or with distinct cross veins (17). Leaf-blade margins cartilaginous (14/14). Leaf-blade apex muticous (435), or pungent (30).
Morphology Reproductive morphology Inflorescences
Synflorescence simple (462), or compound (1); fasciculate (1/1). Inflorescence a panicle (444), or composed of racemes (16), or comprising only a few spikelets (4); terminal (421), or terminal and axillary (43); not deciduous as a whole (458/462), or deciduous as a whole (4/462); subtended by an unspecialized leaf-sheath (461), or an inflated leaf-sheath (1), or a spatheole (1); exserted (440), or embraced at base by subtending leaf (32), or enclosed (1). Spatheole lanceolate (1/1). Peduncle persistent (461), or fracturing (2). Panicle open (417/442), or contracted (26/442), or spiciform (7/442), or capitate (1/442). Primary panicle branches not whorled (419/443), or whorled at lower nodes (22/443), or whorled at most nodes (8/443). Panicle axis bearing persistent branches (443/444), or deciduous branches (1/444). Racemes single (1/16), or borne along a central axis (16/16); appressed (1/16), or ascending (13/16), or spreading (1/16), or drooping (1/16); unilateral (13/14), or paucilateral (1/14); bearing 1-8 fertile spikelets on each (1/1). Central inflorescence axis unspecialized (15/16), or flattened (1/16). Rhachis angular (7/7). Spikelet packing crowded (2/16), or contiguous (14/16); 2 -rowed (1/1). Spikelets appressed (27/32), or ascending (1/32), or spreading (4/32); solitary (433), or in pairs (44), or in threes (2). Fertile spikelets sessile (4/462), or sessile and pedicelled (3/462), or pedicelled (456/462); 1 in the cluster (1/7), or 2 in the cluster (7/7), or 3 in the cluster (1/7). Pedicels filiform (31/47), or oblong (1/47), or clavate (15/47); tip oblique (1/21), or widened (6/21), or discoid (6/21), or cupuliform (8/21).
Morphology Reproductive morphology Inflorescences Spikelets
Spikelets comprising 1 basal sterile florets (461/462), or 2 basal sterile florets (1/462); 1 fertile florets (462), or 2 fertile florets (1); without rhachilla extension (459), or with a barren rhachilla extension (6). Spikelets linear (1), or lanceolate (52), or elliptic (175), or oblong (91), or ovate (166), or orbicular (24), or obovate (30), or oblanceolate (3); of unremarkable solid shape (461), or globose (2); laterally compressed (4), or dorsally compressed (459); symmetrical (450), or gibbous (9), or plano-convex (4); 0.7-2.732-9.2 mm long; persistent on plant (2), or falling entire (460), or breaking up at maturity (1); deciduous from the base (457/460), or with the pedicel (1/460), or with accessory branch structures (3/460). Spikelet callus brief (462), or square (1). Rhachilla internodes brief up to lowest fertile floret (398), or elongated between glumes (64), or elongated below proximal fertile floret (2). Rhachilla elongation stout (1/1). Floret callus brief (457), or evident (6), or elongated (1); without wings (460), or winged (3); with lateral wings (3/3); truncate (1), or obtuse (462).
Fertile
Spikelets comprising 1 basal sterile florets (461/462), or 2 basal sterile florets (1/462); 1 fertile florets (462), or 2 fertile florets (1); without rhachilla extension (459), or with a barren rhachilla extension (6). Spikelets linear (1), or lanceolate (52), or elliptic (175), or oblong (91), or ovate (166), or orbicular (24), or obovate (30), or oblanceolate (3); of unremarkable solid shape (461), or globose (2); laterally compressed (4), or dorsally compressed (459); symmetrical (450), or gibbous (9), or plano-convex (4); 0.7-2.732-9.2 mm long; persistent on plant (2), or falling entire (460), or breaking up at maturity (1); deciduous from the base (457/460), or with the pedicel (1/460), or with accessory branch structures (3/460). Spikelet callus brief (462), or square (1). Rhachilla internodes brief up to lowest fertile floret (398), or elongated between glumes (64), or elongated below proximal fertile floret (2). Rhachilla elongation stout (1/1). Floret callus brief (457), or evident (6), or elongated (1); without wings (460), or winged (3); with lateral wings (3/3); truncate (1), or obtuse (462).
Morphology Reproductive morphology Inflorescences Bracts Glume
Glumes one the lower absent or obscure (1), or two (462); shorter than spikelet (63/462), or reaching apex of florets (394/462), or exceeding apex of florets (9/462); thinner than fertile lemma; parallel to lemmas (414), or recurved at apex (6), or gaping (48). Lower glume linear (1/462), or lanceolate (38/462), or elliptic (6/462), or oblong (13/462), or ovate (385/462), or orbicular (4/462), or oblate (25/462), or obovate (3/462); not clasping (16/60), or clasping (44/60); not gibbous (460/462), or gibbous (2/462); hyaline (16/462), or membranous (446/462), or herbaceous (1/462); without keels (456/460), or 1-keeled (4/460); 0-3-11 -veined. Lower glume lateral veins absent (107/462), or obscure (19/462), or distinct (352/462), or prominent (7/462), or thickened (2/462); without ribs (375/380), or ribbed (5/380). Lower glume surface smooth (447/462), or asperulous (7/462), or scabrous (6/462), or tuberculate (3/462); glabrous (408/462), or puberulous (10/462), or pubescent (30/462), or pilose (29/462), or villous (5/462), or hispid (1/462), or woolly (1/462); without hair tufts (462/462), or with an apical beard (1/462). Lower glume apex entire (458/462), or erose (1/462), or lobed (4/462); 3 -fid (2/2); emarginate (1/447), or truncate (16/447), or obtuse (106/447), or acute (290/447), or acuminate (90/447), or attenuate (1/447), or setaceously attenuate (1/447), or cuspidate (3/447); muticous (453/462), or mucronate (13/462), or awned (5/462). Upper glume lanceolate (24), or elliptic (91), or oblong (31), or ovate (322), or orbicular (3), or obovate (1); not gibbous (462), or gibbous (1); 0.8-1.355-2.5 length of adjacent fertile lemma; membranous (458), or herbaceous (4), or cartilaginous (1); with undifferentiated margins (460), or hyaline margins (3); without keels (458), or 1-keeled (5); wingless (462), or winged on margins (1); 3-7-57 -veined. Upper glume primary vein eciliate (462), or pubescent (1). Upper glume lateral veins without ribs (458), or ribbed (5); without cross-veins (1/3), or transversely connected at apex (2/3), or with cross-veins (1/3). Upper glume surface smooth (436), or asperulous (15), or scabrous (6), or papillose (2), or tuberculate (4), or wrinkled (2), or rugose (1); glabrous (366), or puberulous (27), or pubescent (59), or pilose (39), or hirsute (2), or villous (8), or hispidulous (4), or hispid (2), or woolly (1); with simple hairs (123/136), or tubercle-based hairs (13/136); without hair tufts (462), or with an apical beard (2). Upper glume apex entire (459), or lobed (4); 3-4 -fid (1/2), or 5 -fid (2/2); emarginate (1/451), or truncate (1/451), or obtuse (97/451), or acute (288/451), or acuminate (85/451), or attenuate (2/451), or cuspidate (3/451), or laterally pinched (1/451); muticous (458), or mucronate (6), or awned (4); 1 -awned (4/4).
Morphology Reproductive morphology Flowers Florets
Basal sterile florets male (172/462), or barren (308/462); with palea (323/447), or without significant palea (135/447). Lemma of lower sterile floret lanceolate (23/462), or elliptic (105/462), or oblong (28/462), or ovate (313/462), or orbicular (3/462), or obovate (1/462); 0.95-1.116-1.3 length of fertile lemma; hyaline (2/462), or membranous (456/462), or chartaceous (1/462), or herbaceous (1/462), or scarious (1/462), or cartilaginous (1/462); 3-6-15 -veined; without ribs (460/462), or ribbed (2/462); without grooves (461/462), or sulcate (1/462); truncate (2/435), or obtuse (73/435), or acute (320/435), or acuminate (55/435), or attenuate (1/435), or cuspidate (2/435); muticous (459/462), or mucronate (4/462). Fertile lemma lanceolate (20), or elliptic (229), or oblong (174), or ovate (56), or orbicular (5), or obovate (13); without auricles (462), or thickened on margins at base (1); dorsally compressed (462/462); not gibbous (462), or gibbous (1); chartaceous (20), or cartilaginous (4), or coriaceous (10), or indurate (430); without keel (461/462), or keeled (1/462); wingless (462), or winged on margins (1); 3-4 -veined (2/36), or 5 -veined (17/36), or 6 -veined (3/36), or 7 -veined (20/36), or 8 -veined (1/36), or 9 -veined (3/36). Lemma lateral veins obscure (3/12), or distinct (7/12), or prominent (2/12). Lemma surface smooth (387), or granulose (5), or asperulous (2), or scaberulous (7), or scabrous (1), or papillose (29), or tuberculate (14), or striate (13), or reticulate (4), or punctate (3); unwrinkled (455), or rugulose (4), or rugose (4); glabrous (452), or puberulous (3), or pubescent (6), or pilose (3); with simple hairs (10/12), or clavate hairs (2/12); without hair tufts (462), or with basal hair tufts near margin (1). Lemma margins flat (1), or involute (455), or convolute (8); eciliate (455), or ciliate (5), or pubescent (2), or pilose (1). Lemma apex obtuse (176/342), or acute (137/342), or acuminate (10/342), or apiculate (24/342), or rostrate (2/342); without ornament (419), or laterally pinched (4), or with a little green crest (7), or with a green spot (1), or with a shallow excavation (1), or papillose (1), or scabrous (8), or pubescent (25), or woolly (2); muticous (458), or mucronate (5). Palea embraced by lemma (462), or reflexed at apex (1); not rolled (1), or involute (462); 1 length of lemma; membranous (1), or chartaceous (20), or cartilaginous (3), or coriaceous (10), or indurate (430). Palea surface glabrous (457), or pubescent (2), or pilose (3), or villous (1).
Morphology Reproductive morphology Flowers
Lodicules 2 (7/7); truncate (3/3). Anthers 2 (3/148), or 3 (146/148).
Morphology Reproductive morphology Fruits
Caryopsis with adherent pericarp (181/181); ellipsoid (44/65), or oblong (8/65), or ovoid (12/65), or orbicular (1/65), or obovoid (5/65). Embryo 0.2-0.4095-0.5 length of caryopsis. Hilum punctiform (25/39), or elliptic (14/39).
Distribution
Europe (6), or Africa (175), or Temperate Asia (27), or Tropical Asia (42), or Australasia (40), or Pacific (26), or North America (108), or South America (198).
[GB]

nonem

Morphology General Habit
Annual. Culms erect (1/1), or geniculately ascending (1/1); slender (1/1); 17-50.87-80 cm long. Lateral branches sparse (1/1). Ligule a ciliolate membrane. Leaf-blades linear (3), or lanceolate (1). Leaf-blade margins cartilaginous (2/2).
Morphology Reproductive morphology Inflorescences
Inflorescence a panicle. Panicle open. Panicle axis bearing deciduous branches. Spikelets solitary. Fertile spikelets pedicelled. Pedicels tip cupuliform (2/2).
Morphology Reproductive morphology Inflorescences Spikelets
Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate (1), or elliptic (1), or ovate; dorsally compressed; 2-4.65-7.5 mm long; falling entire. Rhachilla internodes elongated between glumes (2), or elongated below proximal fertile floret. Rhachilla elongation slender.
Fertile
Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate (1), or elliptic (1), or ovate; dorsally compressed; 2-4.65-7.5 mm long; falling entire. Rhachilla internodes elongated between glumes (2), or elongated below proximal fertile floret. Rhachilla elongation slender.
Morphology Reproductive morphology Inflorescences Bracts Glume
Glumes shorter than spikelet (3), or reaching apex of florets (1); thinner than fertile lemma. Lower glume lanceolate (1), or elliptic (1), or ovate; membranous; without keels; 3-4 -veined (1), or 5 -veined (2), or 6 -veined (1), or 7 -veined (3). Lower glume surface smooth (3), or scabrous (1); glabrous (3), or pilose (1). Lower glume apex obtuse (1), or acute (3), or acuminate (1); muticous (3), or mucronate (1), or awned (1). Upper glume lanceolate (2), or elliptic (2), or ovate (1); membranous; without keels; 5-6 -veined (1), or 7 -veined (3), or 8 -veined (1), or 9 -veined (2), or 10-11 -veined (1). Upper glume lateral veins without ribs (2), or ribbed (2). Upper glume surface smooth (3), or scabrous (1); glabrous (3), or pilose (1); with tubercle-based hairs (1/1). Upper glume apex acute (1), or acuminate (3); muticous (3), or awned (2); 1 -awned (2/2).
Morphology Reproductive morphology Flowers Florets
Basal sterile florets barren; without significant palea. Lemma of lower sterile floret lanceolate (3), or elliptic (1); membranous; 9 -veined (1/1); without ribs (3), or ribbed (1); acute (1/3), or acuminate (2/3); muticous (3), or awned (2). Fertile lemma elliptic; chartaceous (1), or indurate (3); without keel; 5-7 -veined (1/1). Lemma margins involute. Lemma apex obtuse (2/2). Palea membranous (2), or chartaceous (1), or indurate (1).
Morphology Reproductive morphology Flowers
Anthers 3 (3/3).
Morphology Reproductive morphology Fruits
Caryopsis with free brittle pericarp (1/1); dorsally compressed (1/1). Embryo 0.5 length of caryopsis. Hilum punctiform (3/3).
Distribution
Australasia.
[GB]

nonem

Morphology General Habit
Annual (6), or perennial (3). Culms erect (5/6), or geniculately ascending (1/6), or decumbent (1/6); 5-40.5-100 cm long. Culm-internodes terete (1/1), or elliptical in section (1/1). Lateral branches lacking (1/4), or sparse (1/4), or ample (2/4). Ligule a fringe of hairs. Leaf-blade margins cartilaginous (1/1).
Morphology Reproductive morphology Inflorescences
Inflorescence a panicle; terminal (5), or terminal and axillary (2); exserted (4), or embraced at base by subtending leaf (3). Panicle open (6), or contracted (2). Spikelets solitary, or in pairs (1). Fertile spikelets pedicelled; 1-2 in the cluster (1/1).
Morphology Reproductive morphology Inflorescences Spikelets
Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate (1), or elliptic (6), or oblong (2), or ovate (1), or oblanceolate (2); dorsally compressed; 2.075-4.416-6 mm long; falling entire. Rhachilla internodes brief up to lowest fertile floret (2), or elongated between glumes (5). Floret callus evident; without wings (1), or winged (6); with free apical wings (6/6); truncate.
Fertile
Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate (1), or elliptic (6), or oblong (2), or ovate (1), or oblanceolate (2); dorsally compressed; 2.075-4.416-6 mm long; falling entire. Rhachilla internodes brief up to lowest fertile floret (2), or elongated between glumes (5). Floret callus evident; without wings (1), or winged (6); with free apical wings (6/6); truncate.
Morphology Reproductive morphology Inflorescences Bracts Glume
Glumes shorter than spikelet (1), or reaching apex of florets; thinner than fertile lemma. Lower glume elliptic (1), or ovate; membranous; without keels; 3-4 -veined (3), or 5 -veined, or 6-7 -veined (2). Lower glume surface smooth (6), or scabrous (1). Lower glume apex acute (5), or acuminate (2), or caudate (1). Upper glume lanceolate (2), or elliptic (4), or oblong (1), or ovate (3); membranous (6), or coriaceous (1); without keels; 5-6 -veined (1), or 7 -veined (6), or 9 -veined (1). Upper glume apex acute (5), or acuminate (3), or caudate (1).
Morphology Reproductive morphology Flowers Florets
Basal sterile florets barren; with palea (2), or without significant palea (5). Lemma of lower sterile floret elliptic (4), or oblong (3), or ovate (3), or orbicular (1); membranous (6), or coriaceous (1); 5 -veined (3/6), or 7 -veined (3/6); acute (4), or acuminate (4), or caudate (1). Fertile lemma elliptic (5), or oblong (1), or ovate (4); chartaceous (1), or indurate (6); without keel; 5 -veined (1/3), or 7 -veined (2/3). Lemma margins involute. Lemma apex obtuse (6), or acute (3). Palea involute; 1 length of lemma; chartaceous (1), or indurate (6).
Morphology Reproductive morphology Flowers
Anthers 3 (4/4).
Morphology Reproductive morphology Fruits
Caryopsis with adherent pericarp (2/2); oblong (1/1). Embryo 0.5 length of caryopsis. Hilum punctiform (1/1).
Distribution
Tropical Asia (1), or Australasia (6).
[GB]

Uses

Use
Several species, known collectively as millets, are important cereal crops, especially in India and southern Europe. Others are important pasture grasses.
[Cayman]

Sources

  • Flora Zambesiaca

    • Flora Zambesiaca
    • http://creativecommons.org/licenses/by-nc-sa/3.0
  • Flora of Somalia

    • Flora of Somalia
    • http://creativecommons.org/licenses/by-nc-sa/3.0
  • Flora of Tropical East Africa

    • Flora of Tropical East Africa
    • http://creativecommons.org/licenses/by-nc-sa/3.0
  • Flora of West Tropical Africa

    • Flora of West Tropical Africa
  • Flora of the Cayman Islands

    • Flora of the Cayman Islands
    • http://creativecommons.org/licenses/by-nc-sa/3.0
  • GrassBase - The Online World Grass Flora

    • Clayton, W.D., Vorontsova, M.S., Harman, K.T. and Williamson, H. (2006 onwards). GrassBase - The Online World Grass Flora.
    • http://creativecommons.org/licenses/by-nc-sa/3.0
  • Herbarium Catalogue Specimens

    • 'The Herbarium Catalogue, Royal Botanic Gardens, Kew. Published on the Internet http://www.kew.org/herbcat [accessed on Day Month Year]'. Please enter the date on which you consulted the system.
  • Kew Backbone Distributions

    • The International Plant Names Index and World Checklist of Vascular Plants 2025. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2023 World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0
  • Kew Names and Taxonomic Backbone

    • The International Plant Names Index and World Checklist of Vascular Plants 2025. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2023 International Plant Names Index and World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0
  • Plants and People Africa

    • Common Names from Plants and People Africa http://www.plantsandpeopleafrica.com/
    • © Plants and People Africa http://www.plantsandpeopleafrica.com http://creativecommons.org/licenses/by/3.0/