POACEAE [GRAMINEAE] GRASS FAMILY

Transcription

1 Plant: annuals or perennials POACEAE [GRAMINEAE] GRASS FAMILY Stem: jointed stem is termed a culm internodial stem most often hollow but always solid at node, mostly round, some with stolons (creeping stem) or rhizomes (underground stem) Root: usually fibrous, often very abundant and dense Leaves: mostly linear, sessile, parallel veins, in 2 ranks (vertical rows), leaf sheath usually open or split and often overlapping, but may be closed Flowers: small in 2 rows forming a spikelet (1 to several flowers), may be 1 to many spikelets with pedicels or sessile to stem; each flower within a spikelet is between an outer limna (bract, with a midrib) and an inner palea (bract, 2-nerved or keeled usually) these 3 parts together make the floret the 2 bottom bracts of the spikelet do not have flowers and are termed glumes (may be reduced or absent), the rachilla is the axis that hold the florets; sepals and petals absent; 1-6 but often 3 stamens; 1 pistil, 1-3 but usually 2 styles, ovary superior, 1 ovule there are exceptions to most everything!! Fruit: seed-like grain (seed usually fused to the pericarp (ovary wall) or not) Other: very large and important family; Monocotyledons Group Genera: 600+ genera; locally many genera WARNING family descriptions are only a layman s guide and should not be used as definitive 2 slides per species

2 POACEAE [GRAMINEAE] ANDROPOGONEAE TRIBE Big Bluestem [Turkey Foot]; Andropogon gerardii Vitman - Andropogoneae (Tribe) [Split] Splitbeard Bluestem; Andropogon ternarius Michx. - Andropogoneae (Tribe) Broomsedge Bluestem; Andropogon virginicus L. var. virginicus - Andropogoneae (Tribe) Silver Beardgrass; Bothriochloa laguroides (DC.) Herter - Andropogoneae (Tribe) Silver Plume Grass; Saccharum alopecuroides (L.) Nutt. Andropogoneae (Tribe) Little Bluestem; Schizachyrium scoparium (Michx.) Nash var. scoparium - Andropogoneae (Tribe) Indian Grass; Sorghastrum nutans (L.) Nash - Andropogoneae (Tribe) Grain Sorghum; Sorghum bicolor (L.) Moench ssp. Bicolor (Introduced, cultivated) Andropogoneae (Tribe) Johnson Grass; Sorghum halepense (L.) Pers. (Introduced) - Andropogoneae (Tribe) Eastern Gama Grass; Tripsacum dactyloides (L.) L. - Andropogoneae (Tribe) Corn; Zea mays L. ssp. Mays (Introduced) - Andropogoneae (Tribe)

3 Big Bluestem [Turkey Foot] p1 Andropogon gerardii Vitman Poaceae (Grass Family); Andropogoneae (Tribe) La Petite Gemme Prairie, Polk County, Missouri Notes: Plant perennial, caespitose, erect, to 2-3+ m; Culm terete, unbranched or few branches, mostly glabrous and USDA often glaucous; Roots fibrous, rhizomes or not; Leaf Blades hairy at base, mid-vein thick, up to 1 cm wide; Leaf Sheaths hairy or not, pilose at collar, sheath open; Ligules membranous and ciliate; Inflorescence of 2-7+ (often 3) spike-like racemes up 10+ cm; Spikelets in pairs (RAME structure) of 1 sessile fertile spikelet with awn up to 2+ cm and 1 pedicellate staminate spikelet without awn (spikelets 1+ cm in length), rachis (axis) and base of spikelets often very hairy; prairies and meadows; summer to early fall (varieties present) Ligule membranous with hairy margin (ciliate), collar pillose

4 Big Bluestem [Turkey Foot] p2 Andropogon gerardii Vitman Paired fertile (sessile) and staminate (pedicellate) spikelets (RAME structure) - separated from inflorescence in flipped photos below Staminate spikelet on pedicel without awn Sessile perfect spikelet with both anthers and stigmas shown Staminate floret on pedicel with anther Sessile perfect spikelet with awn 6-7 mm

5 [Split] Splitbeard Bluestem p1 Andropogon ternarius Michx. Poaceae (Grass Family); Andropogoneae (Tribe) Near Praiarie State Park, Barton County, Missouri USDA Notes: Plant perennial, caespitose, erect, to 1.1+ m; Culm terete, several short branches; Roots fibrous; Leaf Blades less than 4 mm wide, to 30+ mm long, mostly glabrous; Leaf Sheaths mostly glabrous or not; Ligules membranous and often slightly ciliate; Inflorescence of a cluster of usually 2 spike-like racemes, usually above leaf sheaths; Spikelets in pairs (RAME structure) of 1 sessile spikelet (1 lower sterile and 1 upper fertile floret) with upper lemma awn up to 2+ cm and 1 pedicellate staminate (or sterile) spikelet (pedicel usually shorter than sessile spikelet, nodes and pedicel of upper spikelet with white hairs up to 10 mm (see photos on p2); various habitats; late summer to fall (varieties present)

6 [Split] Splitbeard Bluestem p2 Andropogon ternarius Michx. Spikes tend to be nearly straight at maturity Paired RAME structure sessile spikelet (lower sterile and upper perfect floret) and a sterile pedicellate spikelet (spikelet reduced to a glume-like structure) Spikes not hidden in leaf sheaths, at maturity these will split into 2 racemes Reduced Pedicellate spikelet Sessile Spikelet Upper floret lemma with awn somewhat spiraled and bent Abundant silver to grayish white hairs Pedicel about as long or less than sessile spikelet 5 mm Usually 2 RAME spikes per peduncle at maturity

7 Broomsedge Bluestem p1 Andropogon virginicus L. var. virginicus Poaceae (Grass Family); Andropogoneae (Tribe) Near Nixa, Christian County, Missouri Notes: Plant perennial, caespitose, erect, to 2 m, usually shorter; Culm terete, somewhat flattened, many short branches; Roots fibrous, rhizomes present or not; Leaf Blades with mid-vein thick, less than 10 USDA mm wide, to 50+ mm long, glabrous or hairy, variable; Leaf Sheaths hairy or not, keeled, sheath open; Ligules membranous (<1 mm) and ciliate; Inflorescence of 2-5+ clusters (spike-like racemes), forming in multiple leaf sheaths on short branches; Spikelets in pairs (RAME structure) of 1 sessile spikelet (1 lower sterile and 1 upper fertile floret) with awn up to 2 cm and 1 pedicellate staminate (or sterile) spikelet, nodes and pedicel of upper spikelet with white hairs up to 10 mm (see photos on p2); various habitats; late summer to fall (several varieties present)

8 Broomsedge Bluestem p2 Andropogon virginicus L. var. virginicus Inflorescence of RAMES on a usually slightly curved axis of spike-like racemes RAME (1 fertile sessile spikelet and 1 sterile or absent pedicellate spikelet) arrangement of A. virginicus Awn of lemma of sessile spikelet, 10 to 20 mm long, not twisted Pecidellate sterile spikelet absent or much reduced Silver/white hairs from 5-10 mm 3 mm Pedicel of sterile spikelet, usually about twice as long as sessile spikelet Sessile spikelet with 1 lower sterile floret (reduced) and 1 upper fertile floret Inflorescence develops in leaf sheath, opens fully from sheath at maturity, width of leaf sheaths from 3-5 mm RAME internode Callus hairs 1-3 mm

9 Silver Beardgrass p1 Bothriochloa laguroides (DC.) Herter Poaceae (Grass Family); Andropogoneae (Tribe) US HWY 13, Just N of Springfield, Greene County, Missouri Notes: Plant perennial, caespitose, erect, up to 1.2+ m; Culm mostly terete, glabrous, nodes with erect hairs or not; Roots USDA fibrous; Leaf Blades less than 5 mm wide, to 30+ cm long, mostly glabrous with long hairs near base; Leaf Sheaths glabrous; Ligules membranous; Inflorescence a dense panicle to 12+ cm, ascending branches (abundant silver white hairs coloring panicle); Spikelets in pairs (RAME structure) of 1 sessile spikelet 1 lower sterile floret and 1 upper fertile floret with fertile lemma having a spirally twisted awn (up to 20+ mm) on lemma of fertile floret and - 1 pedicellate spikelet, reduced and sterile, shorter than sessile spikelet (see photos on p2); various habitats; late summer to fall

10 Silver Beardgrass p2 Bothriochloa laguroides (DC.) Herter Fertile Lemma awn up to 20+ mm, twisted and bent Abundant silver white hairs give a cottonlike appearance 2+ mm Pedicellate Spikelet 3+ mm Sessile Spikelet Sessile Spikelet Pedicellate Spkelet, reduced and sterile, shorter than sessile spikelet

11 Silver Plume Grass p1 Saccharum alopecuroides (L.) Nutt. Poaceae (Grass Family); Andropogoneae (Tribe) Near Heber Springs, Cleburne County, Arkansas Notes: Plant perennial, caespitose, erect, 1 to 3 m; Culm mostly terete, glabrous except near inflorescence with appressed silky hairs, nodes hairy; Roots fibrous with short thick rhizomes; Leaf Blades less than 30 mm wide, to 60+ cm long, mostly glabrous with long hairs near base; Leaf Sheaths glabrous; Ligules membranous and ciliate; Inflorescence a somewhat dense panicle with ascending branches (abundant silver white to tan hairs coloring panicle); Spikelets in pairs (RAME structure) of 1 sessile spikelet 1 lower sterile floret and 1 upper fertile floret with fertile lemma having a spirally twisted awn (up to 20+ mm) on lemma of fertile floret and - 1 pedicellate spikelet similar to the sessile spikelet (see photos on p2); various habitats; late summer to fall (varieties present) USDA Ligule membranous with some hairs Nodes usually with spreading hairs Mature leaves with thick midrib Rhizomes short and thick

12 Silver Plume Grass p2 Saccharum alopecuroides (L.) Nutt. Hairs of inflorescence silver white to light tan Awns of perfect lemmas of both spikelets 2 to 4 times longer than spikelet, spirally twisted especially toward base RAME structure both sessile and pedicellate spikelets with upper perfect floret and Lower sterile floret Pedicellate Spikelet Sessile Spikelet Spikelet 5.5 mm Upper Culm, below Inflorescence, with appressed silky hairs lower culm mostly glabrous Callus hairs much longer than spikelet Pedicel length less than spikelet length

13 Little Bluestem p1 Schizachyrium scoparium (Michx.) Nash var. scoparium Poaceae (Grass Family); Andropogoneae (Tribe) La Petite Gemme Prairie, Polk County, Missouri Notes: Plant perennial, caespitose, erect, to 2 m, usually shorter; Culm terete, branching at upper nodes; Roots fibrous, rhizomes present or not; Leaf Blades with mid-vein thick, less than 10 mm wide, mm long, glabrous or hairy, variable; Leaf Sheaths USDA hairy or not, pinched at collar, sheath open; Ligules membranous and ciliate; Inflorescence of many terminal spike-like racemes up to 6+ cm from branches; Spikelets in pairs (RAME structure) of 1 sessile to short-stalked fertile spikelet with awn up to 2+ cm and 1 pedicellate staminate (or sterile) spikelet with or without shorter awn on lemma, nodes and pedicel of upper spikelet with white hairs (up to 4-5 mm); prairies and other habitats; summer to fall (several varieties present)

14 Little Bluestem - p2 Schizachyrium scoparium (Michx.) Nash var. scoparium Inflorescence composed of paired spikelets (RAME structure), lower floret fertile, upper pedicellate floret sterile or staminate or absent highly variable species 7 mm Upper sterile or staminate spikelet Lower sessile (or short stalked) spikelet with 1 perfect floret, awn to 20+ mm some may have a sterile floret present as well Pedicel of upper spikelet Abundant white hairs at node (base of sessile or short stalked spikelet) and on pedicel of upper spikelet Single compact raceme

15 Indian Grass p1 Sorghastrum nutans (L.) Nash Poaceae (Grass Family); Andropogoneae (Tribe) La Petite Gemme Prairie, Polk County, Missouri Notes: Plant perennial, caespitose, erect, to 2+ m; Culm terete, somewhat flattened, glabrous; Roots fibrous, short thick rhizomes present; Leaf Blades less than 10 mm wide, to 60+ mm long, mostly glabrous, sharp pointed auricles at base; Leaf Sheaths hairy or not; Ligules membranous and ciliate; Inflorescence a dense panicle, USDA cm long, golden yellow in color; Spikelets in pairs (RAME structure) of 1 sessile spikelet 1 lower sterile floret and 1 upper fertile floret with an awn (up to 20mm) on lemma of fertile floret and - 1 pedicellate staminate (or sterile) spikelet but only the pedicel is present (see photos on p2), sessile spikelet 4 to 8 mm long; various habitats, particularly tall grass prairie; late summer to fall Node densely hairy Infl. Golden yellow Lower surface auricles rhizomes Upper surface Auricles and membranous ligule, ciliate

16 Indian Grass p2 Sorghastrum nutans (L.) Nash Yellow anther and transparent stigma Awn of lemma of upper fertile floret, twisted and often bent toward base 6.5 mm Lower glume Pedicel of second spikelet of RAME struct., spikelet absent Hairy Upper Glume Sessile spikelet 1 lower reduced sterile floret and 1 upper fertile floret

17 USDA Grain Sorghum - p1 Sorghum bicolor (L.) Moench ssp. Bicolor (Introduced, cultivated) Poaceae (Grass Family); Andropogoneae (Tribe) Mingo National Wildlife Refuge, Stoddard County, Missouri Notes: Plant annual, mostly erect, from 0.5 to 2.5 (5-6) m, clump forming or not; Culm terete; Roots fibrous, without rhizomes; Leaf Blades up to 6+ cm wide, to 1 m long, quite variable with cultivars; Leaf Sheaths often glabrous; Ligules membranous; Inflorescence a panicle up to 60+ cm tall, branched; Spikelets arranged in the RAME structure (1 sessile perfect floret and 1 pedicellate sterile floret); fruits up to 6 mm, somewhat ovate to nearly circular; summer to fall (many variants or cultivars)

18 Grain Sorghum p2 Sorghum bicolor (L.) Moench ssp. Bicolor (Introduced) Pedicellate sterile floret Fruit Sessile perfect floret

19 Johnson Grass p1 Sorghum halepense (L.) Pers. (Introduced) Poaceae (Grass Family); Andropogoneae (Tribe) Nixa, Christian County, Missouri Notes: Plant perennial, erect, to 2+ m; Culm terete, nodes swollen USDA and greenish; Roots fibrous, with stout white rhizomes; Leaf blades glabrous, up to but usually less than 1 m, up to 4 cm wide; Leaf Sheaths glabrous, sheath open; Ligules membranous with hairs (ciliate); Inflorescence an open panicle (up to 10 to 50+ cm tall, about half as wide), spreading at maturity; 1-5 spikelet pairs (RAME structure), sessile spikelet up to 7 mm, perfect, glumes hard, shiny with appressed hairs, lemma thin and membranous (hyaline) and awned or not, pedicellate spikelet a little shorter but thinner, staminate, pedicel about 2 to 3+ mm; Glumes enclose florets; Paleas absent; spring to summer Ligule membranous and ciliate Large white rhizomes

20 Johnson Grass p2 Sorghum halepense (L.) Pers. (Introduced) Exposed style 2 nd pair of spikelets (RAME structure) Exposed style Exposed anther staminate spikelet of 1 st pair rachis Pedicel of staminate spikelet perfect, sessile spikelet of 1 st pair

21 Eastern Gama Grass p1 Tripsacum dactyloides (L.) L. Poaceae (Grass Family); Andropogoneae (Tribe) Nixa Area, Christian County, Missouri Notes: Plant perennial, erect, to 2+ m, forms clumps; Culm terete, nodes slightly swollen and greenish; Roots fibrous with short rhizomes; Leaf Blades mostly glabrous, up to 70+ USDA cm; Leaf USDA Sheaths mostly glabrous; Ligules membranous and ciliate; Inflorescence of 1 to several (usually 2 or 3) terminal spikelet racemes; Plant monoecious; 1 pistillate spikelet with 2 florets, one sterile and one fertile, a hard glume surrounds the florets at maturity; Staminate spikelets - paired spikelets, sessile or with very small pedicel, glumes from 0.5 to 1.0+ cm, lemmas smaller and thin; spring to summer [species somewhat variable] Ligule membranous with hairs (ciliate)

22 Eastern Gama Grass p2 Tripsacum dactyloides (L.) L. Terminal Spikelike racemes Monoecious (Imperfect) plant pistillate spikelets below with Staminate spikelets above Anthers Paired Staminate Spikelets, sessile or with very short pedicels Styles Pistillate Spikelets Feathery styles of pistillate floret Lower Glume covers 2 florets, 1 sterile and 1 fertile pistillate floret

23 Corn p1 USDA Zea mays L. ssp. Mays (Introduced) Poaceae (Grass Family); Andropogoneae (Tribe) Near Strafford, Dallas County, Missouri Notes: Plant annual, monoecious; Culm mostly terete, glabrous to hairy, erect, internodes with pith; Roots fibrous, prop roots usually present at lower nodes, height varies; Leaf Blades up to 12+ cm wide, up to75+ cm long; Leaf Sheaths opened, long hairs on edges; Ligules membranous, often lacerated; staminate Inflorescence of 4+ racemes (palmate or pinnate), terminal, spikelets paired with 2 florets; pistillate inflorescence of 1 to 3 spikes (cobs or ears of corn), each covered by bract-like structures (husks), each cob (axis) with many rows of sessile spikelets, 2 florets (1 sterile, 1 fertile), styles (silk) very long and protrudes from ear; summer (cultivated plant)

24 Corn p2 Zea mays L. ssp. Mays (Introduced) 2 pistillate structures (ears) with styles (silk) protruding Paired Staminate Spikelets Terminal Staminate inflorescence (tasels) Pistillate structure ( kernels of corn) Staminate florets