Introductory Grass Identification Workshop University of Houston Coastal Center 23 September 2017

Home , Allolepis, Apera, Blepharidachne, Bothriochloa, Cathestecum, Chondrosum

Broadleaf Woodoats (Chasmanthium latifolia)

Introduction

This 5 hour workshop is an introduction to the identification of grasses using hands- on dissection of diverse species found within the Texas middle Gulf Coast region (although most have a distribution well into the state and beyond). By the allotted time period the student should have acquired enough knowledge to identify most grass species in Texas to at least the genus level.

For the sake of brevity grass physiology and reproduction will not be discussed.

Materials provided:

 Dried specimens of grass species for each student to dissect  Jewelry loupe 30x pocket glass magnifier  Battery-powered, flexible USB light  Dissecting tweezer and needle  Rigid white paper background  Handout: - Grass Plant Morphology - Types of Grass Inflorescences - Taxonomic description and habitat of each dissected species. - Key to all grass species of Texas - References - Glossary

Itinerary (subject to change)

0900: Introduction and house keeping 0905: Structure of the course 0910: Identification and use of grass dissection tools 0915- 1145:  Basic structure of the grass  Identification terms  Dissection of grass samples 1145 – 1230: Lunch 1230 - 1345: Field trip of area and collection by each student of one fresh grass species to identify back in the classroom. 1345 - 1400: Conclusion and discussion

Grass Structure

spikelet pedicel

inflorescence

rachis

culm collar

internode ------leaf blade leaf sheath

node

crown fibrous roots

Grass shoot. The above ground structure of the grass.

Root. The below ground portion of the main axis of the grass, without leaves, nodes or internodes, and absorbing water and nutrients from the soil.

Crown. The persistent base of a perennial grass. Culm (Stem). A major division of the plant body in contrast to root and leaf, distinguished from both by certain anatomical features and commonly also by general aspect; the main axis or axes of a plant; the portion of the plant axis bearing nodes, leaves, and buds and usually found above ground.

- Rhizome. A horizontal, underground stem with modified leaves at the nodes.

- Stolon. A horizontal, above-ground stem with modified leaves, nodes, internodes, and axillary buds.

Node. The joint of a stem; the region of attachment of the leaves.

Leaf sheath. The tubular basal portion of a leaf that encloses the stem. Generally there is a ligule at the inside (adaxial) junction of the leaf sheath and the leaf blade. The ligule is a very reliable vegetative characteristic for grass identification. In 4 some grasses an ear-shaped appendage called an auricle occurs in pairs laterally at the base of the leaf blade and laterally at the sheath apex in others. Its function is to hold the open sheath.

ligule membranous ligule.

ligule ligule Ligule with hairs. Ligule with sheath closed.

Ligule with ciliated ligule membrane

Auricle

Leaf blade. The flattened, expanded portion of leaf above the sheath.

Collar. The outer side of a grass leaf at the junction of the blade and sheath.

Inflorescence. The flowering portion of a shoot; in grasses, the spikelets and the axis or branch system that supports them, the inflorescence being delimited at the base by the uppermost leafy node of the shoot. Grass inflorescences are delimited by the uppermost culm leaf or portion thereof. By 5 this definition, multiple inflorescences can occur on a single culm. The spike, spicate raceme, and raceme inflorescences do not have branches arising from the central axis (rachis). With these inflorescences the spikelets either are attached directly or individually pedicelled (or stalked) upon the central axis.

A panicle inflorescence is anywhere the spikelets are not sessile or individually pediceled on the main axis.

CA Switch Grass

CA – Central Axis S - Spikelet

A spike inflorescences are those in which the spikelets are sessile on the centreal axis or rachis.A raceme inflorescence has pedicels supporting single spikelets, with the pedicel attached to the central axis.

Cheatgrass

A panicle of spicate primary unilateral branches is a common modification of the typical panicle inflorescence. Branches developing from the nodes at the central axis of the inflorescence are called primary branches. Spikelets on this inflorescence type are racemose (subsessile) or spicate (sessile) on the primary branch and make the branch appear spikelike, hence the term "spicate." The spikelets are attached along one side of the branch and give the branch a unilateral or one-sided appearance. Panicles with spicate primary unilateral branches may be described by the arrangement of the branches using modifiers such as alternate, digitate, subdigitate, or verticillate.

PS – Pedicelled Spikelet CA – Central Axis SS – Sessile Spikelet Little Bluestem

A spicate raceme has an unbranched central axis with sessile spikelets and short pedicellate spikelets (PS).

S CA CA

Wild Barley

CA Sideoats Gramma

Panicle of alternate spicate primary unilateral branches

Panicle of subdigitate spicate unilateral unilateral branches.

Panicle of verticillate spicate primary unilateral branches.

Rachis or main axis of the inflorescence. The central stem or branch of the culm or inflorescence in which parts of the grass are arranged.

Pedicel. The stalk of a single spikelet

Spikelet. The basic unit of the grass inflorescence, usually consisting of short axis, the rachilla, bearing 2 empty bracts called the glumes, at the basal nodes and 1 or more florets above. - The rachilla. The main axis of a grass spikelet. 9

Floret. As applied to grasses, the lemma and palea with the enclosed flower; may be perfect, pistillate, staminate, or sterile.

reduced (neuter) floret

awn

palea

stigma rachilla anther floret lemma ovary lodicule

second glume first glume

pedicel

Glumes. The pair of bracts usually present at the base of the grass spikelet. The first glume is lower. Both glumes are usually present, but occasionally the first may be reduced in size or completely absent or both partially fused. Lemma. Part of the second series of bracts of the spikelet. The lemma is probably the most reliable and frequently used character in grass in identification. It is always present and has a high degree of stability within a genus. Lemma texture, shape,

10 number of nerves, awn development, and surface features are used extensively in identification.

- Nerve. A simple vein or slender rib of a leaf or bract (glumes, lemma, and/or palea).

Palea. Part of the second series of bracts of the spikelet. Usually 2-nerved and 2- keeled and often enclosed by the lemma.

- Keel. A prominent dorsal ridge, like the keel of a boat. Glumes and lemmas of laterally compressed spikelets are often sharply keeled. Ovary. Part of the pistil that contains the ovules. - Pistil. The female (seed-bearing) structures of the flower, ordinarily consisting of the ovary, stigma, and style. - Ovules. The structure that develops into the caryopsis (seed). - Caryopsis. The characteristic grass fruit (seed)

Stigma. The part of the ovary or style that receives the pollen for effective fertilization. Anthers. The pollen-bearing part of a stamen.

Workshop Species Dissection Genera Group Key

Group A Spikelets surrounded by a bur-like involucre of prickly spines or smooth scales.

Plants monoecious; burlike structure (fascicle) composed of bristles or flattened spines fused for more than ½ their length; spines sharp enough to puncture flesh

Coastal Sandbur (Cenchrus spiniflex) – Annual, mostly with tall, coarse, stiffly erect culms. Ligule a fringe of hairs. Spikelets enclosed in fascicles with more than 1 whorl of flattened inner bristles usually 1-3 mm wide at base, 8-43 bristles, disarticulating at maturity. Glumes thin, membranous, unequal. Lower glume 1 to 3-nerved, the upper 1-7 nerved. Lemma of the sterile floret thin, 1-7 nerved, equaling or exceeding the upper glume. Palea of the sterile floret about equaling the lemma. Lemma of the fertile floret thin, membranous, 5-7 nerved, tapering to a slender, usually acuminate tip, the margins not inrolled. spikelet palea

lemma upper lower floret glume glume

fascicle

Fascicle cut opened to show seed. 12

Group B. Spikelets unisexual, staminate; pistillate spikelets usually conspicuously different.

Plants monoecious, > 2m tall

Gammagrass (Tripsachum dactyloides) – Large cespitose perennials with stout, thick-based culms and usually broad, flat blades. Inflorescence a spikelike raceme or series of 2 to few spikelike racemose branches bearing staminate spikelets above and pistillate spikelets below. Staminate spikelets 2-flowered, in pairs on one side of a continuous rachis. Pistillate spikelets below the staminate and on the same rachis, single, sessile, an partially embedded on the rachis. Glumes of the staminate spikelet flat, several-nerved, relatively thin. Glumes of the pistillate spikelet hard and boney, fused with the rachis and tightly enclosing the rest of the spikelet. Lemmas of the sterile and fertile florets thin and membranous, awnless, often reduced. Staminate portion of the rachis deciduous as a whole, the pistillate portion breaking up at the nodes into beadlike units.

staminate spikelet pedicel

pistillate staminate spikelet spikelet rame internode lower glume

pistillate spikelet

Group C Spikelets in pairs of 1 sessile and 1 pediceled; lower glumes large and enclosing spikelet.

1. Spikelets all alike and fertile

Big Bluestem (Andropogon gerardii). Cespitose perennials with usually stiffly erect culms, rounded or flattened and keeled sheaths, and flat or folded blades; ligules membranous. Flowering culm little-branched above the base. Each culm or branch terminated by an inflorescence of 2 to several racemose branches. Sessile spikelets with awn 8-25 mm long; rhizomes sometimes present, the internodes usually <2 cm long. Pediceled spikelet well developed. Disarticulation in the rachis, the sessile spikelets falling attached to the associated pedicel and section of the rachis. Glumes large, firm, awnless. Lemmas of the sterile and fertile florets membranous, lemma of the fertile floret awned.

1. Spikelets not all alike; sessile or pediceled ones staminate or sterile………………2 2. Spikelet awnless; flowering culms terminating in panicles with numerous branches.

Johnsongrass (Sorghum halepense). Rhizomatous perennial with tall, stout culms. Caryopses not exposed at maturity. Blades long, flat, narrow, or broad. Inflorescence a large, open or contracted panicle, the spikelets clustered on short racemose brachlets. Spikelets in threes at the branchlet tips, 1 sessile and fertile and 2 pediceled and staminate or neuter and below the tips in pairs of 1 sessile and perfect and 1 pediceled and reduced. Disarticulation below the sessile spikelet. Glumes coriaceous, awnless, about equal in length. Lemma of the sterile floret and lemma and palea of the fertile floret membranous, the lemma of the fertile floret usually with a geniculate and twisted awn, this readily deciduous.

pedicellate spikelet

sessile spikelet

pedicellate spikelet sessile spikelet terminal spikelet unit

2. Spikelets, at least some, awned; terminal inflorescences without elongated rachises; pediceled spikelets sterile or staminate, unawned; sessile spikelets perfect, awned.

Little Bluestem (Schizachyrium scoparium). Cespitose perennial, sometimes rhizomatous. Culms to 2 m long. Sheaths rounded or keeled. Ligules 0.5-2.0 mm long. Awns 2.5-17 mm long. Pedicellate spikelets staminate or sterile, unawned or awned, awn to 4 mm long. Widespread and common species of open woodlands, grasslands, and prairies. var. divergens. Pedicellate spikelets 5-10 mm long, usually staminate; sheaths and blades usually Tomentose var. scoparium. Pedicellate spikelets 1-6 mm long, usually sterile; sheaths and blades usually glabrous.

distal end of rame internode

rame

pedicellate spikelet sessile spikelet

rame internode

upper lemma pedicellate spikelet

collar sessile spikelet

var. scoparium var. divergens

Group D Reduced floret1, below the perfect floret; lemma of reduced floret similar to upper glume in shape, size, and texture; disarticulation below the glumes

1. Spikelets in involucres of bristles or flattened spines, these disarticulating with spikelets…...... …………………...………Coastal Sandbur (Cenchrus spiniflex) 1. Spikelets not as above……………………………………...………….………..2 2. Upper glumes awned; first glumes awned or lacking

Barnyard Grass (Echinochloa crusgalli) – Annual, usually with culms to 2 m tall. Sheaths glabrous, ligules absent. Spikelets disarticulating at maturity; upper lemma not exposed at maturity. Panicle branches rebranched, sometimes inconspicuously so, usually > 2 cm long; upper lemmas broadly ovate or elliptic, sometimes with a line of minute hairs across the base of an early-withering tip, apex rounded or broadly acute, abruptly transitioning into a membranous tip, a line of hairs present at the base of the tip.

Barnyard Grass

2. Upper glumes unawned; lower glumes awnless………...... ……...... ……..3 3. Upper lemmas and paleas cartilaginous and flexible at maturity; lemma margins flat, membranous, not involute, and clasping palea; lower glumes absent or less than ¼ the length of the spikelet

Hairy Crabgrass (Digitaria cilliaris) – Annual with decumbent culms that root at the nodes. Sheaths with papillose-based hairs. Panicles of 2-10 spikelike primary branches; winged; wings more than ½ as wide as the midribs. Neither stoloniferous nor rhizomatous. Upper lemmas variously colored but not brown and not turning a dark brown with maturity. Lateral veins of the lower lemmas smooth throughout or only scabrous on the lower third; lower lemma of the lower spikelet of each pair 5-7 veined, the 2 or 3 veins on each side crowded together near the margins and well separated from the midrib. A common species of disturbed sites throughout Texas.

lower lemma lower glume

spikelet

upper lemma

upper glume

spikelet

3. Upper lemmas and paleas chartaceous to indurate and rigid at maturity; lemma margins involute and clasping paleas; lower glumes present or absent………………………………………………………………….….4

4. Lower glumes absent on some or all spikelets, < 1 m tall

Bahiagrass (Paspalum notatum) – Perennial with thick, entrenched rhizomes. Culms to 1.5 m long, erect; ligules 0.2-0.5 mm long. Panicle with a terminal, digitate pair of branches with 1-3 additional branches below. Upper glumes glabrous; spikelets ovate, apices obtuse to broadly acute, 1.9-2.3 mm long.

spikelet

lower lemma

spikelet

upper glume spikelet

4. Lower glumes present on all or some spikelets, > 1 m tall

Switchgrass (Panicum virgatum) – Rhizomatous perennial. Culms to 3 m tall, solitary or forming large clumps. Ligules a fringed membrane, 1.5-6 mm long. Panicles 10-55 cm long, open. Lower floret staminate; lower glumes 1.8-4.0 mm long; more than ½ as long as spikelet; lower paleas hastate-lobed. Plants pilose at least at base of blades.

upper glume lower lemma

lower glume

spikelet

Group E. One perfect floret; reduced florets if present above the perfect one; panicle inflorescence, never spicate

1. Glumes and lemmas awnless

Rattail Smutgrass (Sporobolus indicus) – Perennial. Culms to 1 m long, usually much shorter. Panicles narrow, tightly contracted. Lower sheath round. Spikelets 2.0-2.6 mm long; glumes about equal, upper glumes usually ½ to two-thirds as long as the floret, acute to obtuse, entire. Found in disturbed sites in both clayey and sandy soils. Spikelets often infected with a fungus that leaves a black smut on hands and clothing.

spikelet

1. Glumes or lemmas awned………………………………………………...…...... 2 2. Lower glumes 3-7 veined; lateral awns no more than ½ as long as central awn, sometimes absent

Oldfield Threeawn (Aristida oligantha) – Annual with highly branched culms. It occurs in fallow or abandoned fields along roadsides and railroads and in other waste places.

lemma glume

2. Lower glumes 1-2-, rarely 3-, veined; lateral awns well developed, at least ½ as long as central awns.

Slimspike Threeawn (Aristida longespica) – Annual, often with spreading to sometimes prostrate culms. Found along roadsides, sandy fields, and woodland openings.

3. Central awns 1-15 mm long and/or lateral awns usually 0-5 mm long ....……...………….……………………………………………var. longespica 3. Central awns 8-30 mm long, lateral awns 6-20 long……….……var. geniculata

spikelet

var. longespica

var. geniculata

Group F. Inflorescence of 1 to several unilateral spicate primary branches 1. Spikelets with 2 or more perfect florets.

Tumble Windmillgrass (Chloris verticillata). Perennial with flowering culm from erect bases, sometimes rooting at the nodes. Lower portion of culms laterally compressed. Sheaths sharply keeled. Panicle inflorescence with branches 10-16, in several distinct, well-separated whorls and a solitary vertical terminal branch. Entire inflorescence disarticulates, panicle falling intact. Spikelets with a single perfect floret and 1-3 staminate or rudimentary florets above. Disarticulation above the glumes. Glumes thin, lanceolate, 1-nerved, strongly unequal. Lemmas broadly to narrowly ovate , awned from a minute, bifid apex, 1-5 nerved, but usually with 3 strong glabrous veins, Palea well developed, strongly 2-nerved. A common weed of roadsides, waste areas, lawns and disturbed sites.

florets

glume s

1. Spikelets with 1 perfect floret.

Gulf Cordgrass (Spartina spartinae) – Large clumped perennial with no rhizomes. Panicle 670 cm long, cylindrical with 15-75 appressed branches. Ligules 1-2 mm long. Lower glumes nearly as long as spikelet, hispid on keels. Grows in marshes and ditches and along roadsides, sandy beaches and coastal salt flats.

lower upper glume glume spikelet

Group G. Inflorescence a terminal, bilateral spike or spicate raceme

Virginia Wildrye (Elymus virginicus) – Perennial. Spikelets 2-5 at all or most nodes; glumes usually with terete, indurate bases, 2-5 (-8) veins, widening or parallel above the base, 0.2-2.3 mm wide; disarticulating; spikes erect, <2.5 cm wide including awns; glume awns 0-10 (-15) cm long. Lemma awns 5-20 mm long at midspike; lower leaf blades not markedly smaller or less persistent than upper blades. Rachises not disarticulating at maturity.

1. Spikes partially sheathed; glumes `.0-2.3 mm wide, bowed in the basal 2-4 mm; plants not glaucous, yellowish-brown or purplish at maturity……….. var. virginicus 1. Spikes mostly exserted; glumes 0.5-1.8 mm wide, bowed in the basal 1-2 mm; plants usually glaucous, yellowish or reddish-brown at maturity………………...var. jejunus

spikelet

glume glume spikelet

auricles ligule

var. virginicus var. jejunus

Group H. Two or more fertile florets per spikelet; inflorescence an open or contracted panicle or raceme with spikelets on well-developed pedicels. Lemmas with 3, usually conspicuous, veins

1. Inflorescence spicate

Longspike Tridens (Tridens strictus) – Perennial with short, knotty, hard rhizomatous bases. Culms to 1.7 m long. Panicles dense, branches appressed. Found in Coastal grasslands, open woods, old fields and roadsides, mostly on sandy soils but occurs on clayey soils as well.

palea lemma

floret

lemma

floret

glume

1. Inflorescence open

Broadleaf Woodoats (Chasmanthium latifolia) – Rhizomatous perennial with culms to 1.5 m tall. Leafy for 80% of its height. Spikelets with 6-25 florets lower 1-3 sterile, fertile ones diverging at about 45o. Widespread and abundant species in woodlands, in forest openings, and along stream banks. Inflorescence with drooping branches; pedicels 10-30 mm long; spikelets 20-50 mm long.

spikelet

lemma palea

floret

sterile floret glume glume spikelet

Group Key to the Grass Genera of Texas

1. Culms perennial, usually woody; often developing complex branching systems; upper leaves pseudopetiolate (Bambuseae)….………...…………………...Group 1 1. Culms annual, rarely woody; sometimes branching above but not developing complex branching systems; leaves not pseudopetiolate. 2. Spikelets or florets contained within burlike structure, disarticulation below that structure...... Group 2 2. Spikelets or florets not contained within burlike structure. 3. Spikelets unisexual, staminate, and pistillate spikelets usually conspicuously different….…………...……………………………...... ……………..Group 3 3. Spikelets perfect, or if unisexual, then staminate and pistillate spikelets not readily distinguishable. 4. Spikelets with a single fertile floret, with or without reduced florets. 5. Spikelets in pairs of I sessile and 1 pediceled (sometimes 2 pediceled spikelets at branch tips); sessile spikelets fertile; pedicellate spikelets staminate, rudimentary, or absent with pedicel still obvious; lower glume large, firm, and tightly clasping, or enclosing the entire spikelet ……...………………………………...(Tribe Andropogoneae) Group 4 5. Spikelets not as above. 6. Inflorescences with 2 morphologically distinct spikelet forms ……………………………………………………………….Group 6 6. Inflorescences with all spikelets morphologically similar. 7. Reduced floret or florets present below fertile floret. 8. Reduced floret 1; lemma of reduced floret similar to upper glume in shape, size, and texture; disarticulation below the glumes (Paniceae)………………...………...…………….………Group 5 8. Reduced floret 1 or 2; lemma of reduced floret(s) not similar to upper glumes in shape, size, or texture; disarticulation above the glumes…………………………………………...……….Group 6 7. Reduced floret absent or above the fertile florets. 9. Inflorescence paniculate, never spicate……….…....……...Group 7 9. Inflorescence a spike, spicate, or with 2 to several spicate primary branches. 10. Inflorescence of 1 to several unilateral spicate primary branches………………...…………...……………….Group 8 10. Inflorescence a terminal, bilateral spike or spicate raceme ……………………………………………………… Group 9 Gr 4. Spikelets with 2 or more fertile florets. 11. Inflorescence a spike or spicate raceme, or with 2 to several spicate primary branches 12. Inflorescence with 2 (rarely 1) to several unilateral

spicate primary branches...……..…………...Group 10 12. Inflorescence a terminal, bilateral spike or spicate raceme…………... ……………...... Group 9 11. Inflorescence an open or contracted panicle or raceme with spikelets on well-developed pedicels…...... Group 10

Bambusa

Bambusa pachymorphic rhizome

groove

young culm shoot Leptomorphic rhizome

Phyllostachys

Leptomorphic rhizome

Arundinaria compressedmm 5 basal internodes

branch complement At midculm node Group 1

Culms perennial, usually woody; often developing complex branching systems; upper leaves usually pseudopetiolate (Bambuseae)

1. Rhizomes pachymorphic, short, thicker than the culms……....…………….Bambusa 1. Rhizomes leptomorphic, long, thinner than the culms. 2. Culm internodes grooved their entire length; branches usually without compressed internodes; spikelets sessile……………………………...Phyllostachys 2. Culm internodes usually terete, not grooved their entire length; branches usually with 1—5 compressed internodes; spikelets pediceled…....…………..Arundinaria

Group 2

Spikelets or florets contained within burlike structure, disarticulation below that structure

1. Glumes with hooked spines………………………………………………….Tragus 1. Glumes without hooked spines 2. Plants dioecious; burlike structure formed by a cluster of spikelets whose lower portion of upper glumes arc indurate, white, terminating in several awnlike teeth ...…………………………………………………………………….…....Buchloë 2. Plants not as above 3. Burlike structure a reduced inflorescence branch 4. Axes of the branches extending beyond the base of the distal spikelet 5. Panicle branches deciduous……………………...………..….....Bouteloua 5. Panicle branches persistent…………………...……………...Chondrosurn 4. Axes of the branches terminating at the base of the distal spikelet 6. Spikelets in pairs; panicle branches often fused to the rachises.…Lycurus 6. Spikelets in triplet; panicle branches sometimes appressed but not fused to rachis 7. Branches straight at the base. 8. Glumes thickened, hardened, and conspicuously fused at base ……………………………………………………………..Hilaria 8. Glumes papery or membranous, not fused at base..……....Pleuraphis 7. Branches sharply curved at the base…...………...…....…....Cathestecurn

3. Burlike structure (fascicle) composed of bristles or flattened spines. 9. Fascicles composed of flattened spines fused for more than ½ their length; spines sharp enough to puncture flesh…..…Cenchrus 9. Fascicles composed of bristles; bristles free for more than ½ their length; spines not sharp enough to puncture flesh ……………………………………………………….Pennisetum

spikelet

1 glumes glume

glume Tragus

spikelets mm 2 Buchloë inflorescence branch upper Bouteloua upper lemma lemma lemma

palea Hilaria

glume glume florets florets fascicle of spikelet lower lower dorsal view floret floret glumes floret Chondrosum

glumes Chondrosum

glumes Lycurus

distal inflorescence branch Fascicle of spikelets

Pleuraphis primary Cathestecum bristle spikelet 2 mm palea

lemma

lower upper floret spikelet

glume glume 2 mm 2 fascicle

Cenchrus Pennisetum 34

Group 3 Spikelets unisexual, staminate; pistillate spikelets usually conspicuously different

1. Plants monoecious. 2. Pistillate spikelets concealed with au indurate, globose, beadlike structure...…Coix 2. Pistillate spikelets not as above. 3. Plants low, stoloniferous……...………………………………….….Scleropogon 3. Plants usually I m or more in length; cespitose, with a single culms or submerged with floating culms. 4. Plants submerged with floating culms…………...…………..……….Luziola 4. Plants usually 1 m or more in length; cespitose, with a single culm. 5. Pistillate and staminate spikelets in the same inflorescence; staminate spikelets distal to the pistillate spikelets…….……...………...…..Tripsacum 5. Pistillate and staminate spikelets in different inflorescences; staminate inflorescences terminal on culm and branches; pistillate inflorescences terminal on axillary peduncles, sometimes clustered in false panicles….Zea 1. Plants, at least a majority, dioecious. 6. Staminate and pistillate spikelets markedly different in structure. 6. Pistillate spikelets in burlike clusters hidden in the leafy portion of the plant, staminate spikelets sessile on 1—4 short spicate branches of a well-exserted inflorescence……………………...………………………………………Buchloë 7. Pistillate spikelets long-awned from the nerves of each lemma; staminate spikelets awnless; both spikelet types in contracted, usually spikelike racemes ……………………………………………………………………..Scleropogon 7. Staminate and pistillate spikelets similar in structure but may vary in size and sometimes number of florets per spikelet. 8. Plants stoloniferous; leaf blades up to 1.5 cm long……………Monanthochloë 8. Plants rhizomatous; leaves >1.5 cm long…...………………...……Distichlis

staminate spikelets pistillate monoecious

florets

inflorescence staminate floret mm

stigma

1 1 mm 1 involucre immature mature Coix, female Scleropogon, female achene Luziola

staminate spikelets

pistillate spikelets

mm 20 20

Zea

Tripsacum

monoecious inflorescence 36

Scleropogon mm 1

staminate floret

pistillate inflorescence

spikelet pistillate floret

staminate plant

glume staminate spikelet glume glume spikelet Scleropogon, male spikelets Buchloë monoecious inflorescence

pistillate spikelet

floret pistillate floret

florets

staminate floret pistillate staminate spikelet Monanthochloë spikelet

Distichlis

Group 4

Spikelets in pairs of 1 sessile and1 pediceled; lower glumes large and enclosing spikelet (Tribe Andropogoneae)

1. Spikelets all alike and fertile (this includes those genera where the pediceled spikelet is completely reduced and only a naked pedicel remains and those with both sessile and pediceled spikelets fertile and alike)………………...…….…………………..A 1. Spikelets not all alike; the pediceled one (or less frequently the sessile one) is staminate or sterile………………...………………………….………………...AA

A. Spikelets all alike and fertile

1. Pediceled spikelet completely reduced, only sessile remaining. 2. Plants sprawling annuals; blades ovate; pedicels absent or <3 mm long ………………………..…………………………………...………..Arthraxon 2. Plants erect perennials; blades linear to lanceolate; pedicels always present, >3 mm long. 3. Peduncles and branches not subtended by a modified leaf; inflorescences large terminal panicles…………………..………………………Sorghastrum 3. Peduncles subtended, and often partially enclosed, by a modified leaf; inflorescences terminal and axillary, composed of digitate clusters of rames on a common peduncle………………………..………….……..Andropogon 1. Pediceled spikelets present and like sessile spikelets. 4. Plants annual; blades 3—10 cm long; inflorescence branches 2—6 …………………………………..…………………………..Microstegium 4. Plants perennial; blades elongate, at least some mature ones >10 cm long; inflorescence branches numerous. 5. Spikelets falling separately from a persistent rachis. 6. Spikelets awned; inflorescence branches usually 7—35 cm long Miscanthus 6. Spikelets unawned; inflorescence branches 1—7 cm long….Imperata 5. Spikelet falling in pairs with sections of a disarticulating rachis (rames) ………………………………………………………..……..Saccharum

AA. Spikelets not all alike; sessile or pediceled ones staminate or sterile

1. Spikelet awnless 2. Flowering culms terminating in panicles with numerous branches.....…...Sorghum 2. Flowering culms terminating in spicate racemes. 3. Pedicels, at least partially, fused with rachises. 4. Plants annual.

rame rudimentary pedicel pedicel sessile sessile spikelet spikelet rame pedicellate internode spikelet

Arthraxon sessile spikelet

sessile spikelet rame internode pedicel

Pedicellate Sorghastrum spikelet

pedicel

Andropogon sessile spikelet rame segment Microstegium Miscanthus pedicellate spikelet

sessile spikelet pedicel awn

sessile spikelet

flowering pedicellate sessile spikelet spikelet spikelet Sorghum Section of branch terminal Imperata (spikelets removed) spikelet unit

Saccharum 39

5. Sessile spikelets globose, conspicuously alveolate...... ….Hackelochioa 5. Sessile spikelets not globose or alveolate. 6. Sheaths with stiff, papillose-based hairs 1—3 mm long, causing skin Irritation……………………………...…………………………...Rottboellia 6. Sheaths without irritating hairs, often inflated...... Hainardia1 4. Plants perennial...... Hemarthria 3. Pedicles appressed but not fused to the rachises. 7. Keels of the lower glumes with spinelike projections….………Eremochloa 7. Keels of the lower glumes without spinelike projections. 8. Pedicellate spikelets 1—3 mm long……………....……….....Coelorachis 8. Pedicellate spikelets 4—8 mm……….…...... Elionurus 1. Spike lets, at least some, awned 9. Terminal inflorescences with elongated rachises. 10. Rame internodes and pedicels with a translucent median line, central groove, or membranous……………………..Bothriochloa 10. Rame internodes and pedicels with a translucent median line, central groove, or membranous area. 11. Sessile spikelets terete or laterally compressed…...Chrysopogon 11. Sessile spikelets dorsally compressed………………..…Sorghum 9. Other couplet on page 42

1 Hainardia is in the tribe Poeae, not Andropogoneae. It is often mistaken for the latter, however, because its embedded spikelets and fleshy rachis are similar to those found within the Andropogoneae. LI the spikelet structure of Stenotaphrum of the Paniceae is misinterpreted, it is sometimes mistakenly keyed to this vicinity as well 40

spikelet upper pedicellate glume spikelet pedicellate floret spikelet sessile sessile spikelet spikelet Spikelet upper pair glume rachis Rottboellia internode

pedicel Hainardia Hackelochloa spikelet

pedicellate spikelet pedicellate sessile pedicel pedicellate spikelet spikelet sessile spikelet spikelet pedicel sessile spikelet

rame pedicellate spikelet sessile spikelet sessile Coelorachis spikelet Eremochloa rame pedicellate internode spikelet

Hemarthria

pedicellate spikelet pedicellate spikelet pedicel sessile sessile spikelet sessile spikelet Elionurus spikelet rame internode Chrysopogon Bothriochloa 41

9. Terminal inflorescences without elongated rachises. 12. Rame internodes and pedicels with a translucent median line, central groove, or membranous area……...………………………….……………...….Bothriochloa 12. Rame internodes and pedicels without a translucent median line, central groove or membranous area. 13. Sessile and pedicellate spikelets differ in sexuality (heterogamous). 14. Pediceled spikelets perfect, awned; sessile spikelets sterile or staminate, unawned………………………………………....…….…….Trachypogon 14. Pediceled spikelets sterile or staminate, unawned; sessile spikelets perfect, awned. 15. Rames 1 (—2) on peduncles; lower glumes of sessile spikelets veined between keels…………………………………………....Schizachyriun 15. Rames 2—15 on peduncles; lower glumes of sessile spikelets without veins between keels.…………...………………….…....…Andropogon 13. Basal spikelet pairs on each rame with same sexuality (sterile or staminate) (homogamous). 16. Rames with 3—10 homogamous spikelet units; awns 5—15 cm long, becoming twisted together at maturity..…..…..…Heteropogon 16. Rames with 1—2 homogamous spikelet units; awns 1—5 cm (rarely up to 20 cm) long. 17. Inflorescences terminal on culms, axillary inflorescences absent or rare…….……..……………………...…Dichanthium 17. Inflorescences terminal and axillary, axillary numerous. 18. Homogamous spikelets distinct and forming an involucre around the rame base…...………………………...Themeda 18. Homogamous spikelets not distinct and not forming an involucre around the rame base……...……….Hyparrhenia

pedicellate spikelet rame internode

upper lemma glume subsessile pedicellate spikelet spikelet pedicellate spikelet sessile spikelet sessile spikelet Schizachyrium

pedicellate spikelet pedicellate pair Bothriochloa Trachypogon

pedicellate spikelet

sessile spikelet rame segment sessile spikelet

Dichanthium

Heteropogon Andropogon

pedicellate spikelet

spikelet pair

leaf

rame rame cluster

Themeda Hyparrhenia

Group 5 Reduced floret 1, below the perfect floret; lemma of reduced floret similar to upper glume in shape, size, and texture; disarticulation below the glumes (tribe Paniceae) 1. Inflorescences spikelike with the branches embedded in a thick, flattened rachis ...………………………………………………………………………Stenotaphrum 1. Inflorescences panicles, or if spikelike, branches not embedded or rachis not flattened. 2. Spikelets in involucres of bristles or flattened spines, these disarticulating with spikelets. 3. Bristles and/or spines (at least some) fused together for ½ their length 3. Bristles and/or spines not fused together or fused less than ½ their length …………………...……………………………………………...….Pennisetum 2. Spikelets not in involucres; bristles persistent; not disarticulating when present. 4. Upper glumes awned; first glumes awned or unawned. 5. Spikelets and upper florets laterally compressed; lower glumes minute …………………..………………………………………………Melinis 5. Spikelets and upper florets dorsally compressed; lower glumes well developed. 6. Lower glumes much shorter than upper; blades linear to linear- lanceolate, midrib prominent, ligules usually absent….……Echinochloa 6. Lower glumes about equal to upper; blades triangular to lanceolate, midrib not prominent; ligules present on all leaves…...……Oplismenus 4. Upper glumes unawned; lower glumes awned. 7. Upper lemmas and paleas cartilaginous and flexible at maturity; lemma margins flat, membranous, not involute, and clasping palea; lower glume absent or less than ¼ the length of spikelet. 8. Inflorescence simple panicles with erect to ascending branches on elongate rachises; branches not spikelike……..…..Anthenantia 8. Inflorescences usually panicles of digitate or subdigitate clusters of spike-like branches, or simple panicles with strongly divergent branches………………………………………………Digitaria 7. Upper lemmas and paleas cartilaginous to indurate and rigid at maturity; lemma margins involute and clasping paleas; lower glumes present or absent. 9. Lower glumes absent on some or all spikelets. 10. Spikelets subtended by a cuplike callus….…...…...Eriochloa 10. Spikelets not subtended by a cuplike callus. 11. Lemma of upper (fertile) florets with rounded back turned away from rachises; spikelets borne singly and widely spaced in 2 rows………….…………...Axonopus 11. Lemma of upper (fertile) florets with rounded back turned toward the rachises; spikelets closely spaced and often paired in 2 or 4 rows…..………….Paspalum 44

9. Lower glumes present on all or some spikelets. 12. Ligules absent on most or all leaves………………...……………….Echiriochloa 12. Ligules present on most or all leaves. 13. Palea of lower florets inflated at maturity; lower and upper florets separated at maturity………………………………………………………..Steinchisma 13. Palea of lower florets not inflated; lower and upper florets closely appressed at maturity. 14. All or most spikelets subtended by bristles, or branches extending beyond distal spikelet as distinct bristles…………………...…………...A 14. All or most spikelets not subtended by bristles………...…………….AA

A. Spikelets, at least distal ones, subtended by 1 or in ore stiff bristles or extensions of panicle branch 1. Spikelets, all or some (at least, those terminating branchlets), subtended by 1 to several stiff bristles. 2. Spikelets subtended by 1 to many bristles; paleas of lower florets usually hyaline to membranous at maturity, rarely absent or reduced; palea veins not keeled …………………………………………………………………………....Setaria 2. Spikelets subtended by a single bristle; paleas of lower florets coriaceous to indurate at maturity, keels thickened..…………………………...…...….Ixophorus 1. Spikelets not subtended by stiff bristles, but branch axes extending past terminal spikelets as a bristle 2—4 mm long...………………….………………...Paspalidium

AA. Spikelets not subtended by stiff bristles 1. Upper lemmas rugose and verucose. 2. Inflorescences of 1-sided, spikelike primary branches..…… …………….Urochloa 2. Inflorescences a panicle with well-developed primary, secondary, and tertiary Branches..……………………………………………..………………..Megathyrsus 1. Upper lemmas usually smooth; if rugose, the panicle branches neither verticillate nor 1-sided and spikelike. 3. Upper florets stipitate. 4. Upper glumes gibbous...….………………....……………………..Sacciolepis 4. Upper glumes not gibbous………….…………………...…….….Moorochloa 3. Other couplet on page 47.

palea

lemma

lower floret upper lower upper lemma upper upper lemma lemma lower lemma glume upper glume lemma upper upper glume glume spikelet palea lower Setaria lower Steinchisma glume glume

Echinochloa upper glume

spikelet palea spikelet lemma

lower lower upper lemma lemma palea glume lemma upper lemma lower floret upper lower glume glume spikelet lower spikelet upper floret lower glume Urochloa bristle lemma Paspalidium

Ixophorus

branch axis

lower floret

upper floret

glume glume spikelet upper spikelet floret Sacciolepis Moorochloa Megathyrsus

46 Ixophorus

3. Upper florets not stipitate. 5. Panicle branches 1-sided. 6. Spikelets 5—7 mm long; upper floret less than ½ as long as spikelets ...…………………………………………………………………..Phanopyrum 6. Spikelets floret as above. 7. Lower glumes about 3/4 as long as spikelets; spikelets terete or only slightly laterally compressed; stoloniferous with villous nodes……………...….Hopia 7. Lower glumes not more than ½ as long as spikelets; spikelets obviously laterally compressed; stoloniferous or not. 8. Culm bases cormlike…...……………..………………………….Zuloagaea 8. Culm bases varied, but not cormlike...………………….…………Panicum 5. Panicles simple or well developed but not 1-sided. 9. Basal leaves developing a distinctive winter rosette….....…...Dichanthelium 9. Basal leaves not developing a distinctive winter rosette. 10. Primary inflorescences appearing midspring; axillary inflorescences appearing in summer and rebranching by fall; upper florets not disarticulating, plump..…………….…………………...Dichanthelium 10. Primary inflorescences appearing midsummer; axillary inflorescences rare, but if present, usually not rebranching; upper florets either disarticulating or not plump. 11. Culm bases cormlike……………………………….…...Zuloagaea 11. Culm bases various, but not cormlike.….………………..Panicum

palea

lemma upper floret lower upper lemma glume upper floret spikelet

lower Zuloagaea glume

spikelet spikelet Hopia

Phanopyru m lower lemma lower upper glume spikelet glume

upper lower glume lemma lemma palea

lower scar glume upper spikelet floret

Panicum

Dichanthelium

Group 6 Spikelets of 2 morphologically different types or reduced florets 1 or 2, below perfect florets; lemma of reduced florets not similar to upper glumes in shape, size, or texture; disarticulation various, but generally below the glumes2

1. Spikelets of 2 morphologically different types 2. Spikelets in pairs, pedicels not fused at base; disarticulation above the glumes …………………………………...…………………………………….Cynosurus 2. Spikelets in fascicles, pedicels fused at base; disarticulation at the base of fused Pedicels...……..……………………………………………………….Lamarckia 1. Spikelets of a single morphological type. 3. Lemma of perfect floret with 9 subequal, plumose awns..…….……Enneapogon 3. Lemma of perfect floret awnless or with a single awn. 4. Spikelets with 3 well-developed, obvious florets. 5. Lower glume much shorter than the second; foliage sweet smelling ...…………………………….……………………………..Anthoxanthum 5. Lower glume equaling the second in length; foliage not sweet smelling …………………………………………………………………..Ehrharta 4. Spikelets with 1 or 2 well-developed florets, reduced florets inconspicuous And attached below perfect floret. 6. Well-developed florets 1, lemmas awnless. 7. Plants annual…..……………………………………………Phalaris 7. Plants perennial…………………………………………..Phalaroides 6. Well-developed florets 2, first or second lemma awned...……….Holcus

2 This is a notoriously confusing and tricky group. The 2 spikelet types in Cynosurus and Larnarckia, one sterile and one bisexual, are confusing and difficult to distinguish. One of the sterile florets in Ehrharta is actually larger than the bisexual one, and the species is often misinterpreted as having 2 perfect florets rather than just 1. The 2 reduced florets below the upper floret in Phalaris and Phalaroides appear to be pubescent veins, and they usually are not correctly interpreted unless they are “teased” away from the fertile lemmas with a dissecting needle.

glume

glume floret glume reduced floret bisexual floret

glume sterile fertile upper lower floret spikelet glume glume fertile spikelet Cynosurus Spikelet pair

Lamarckia

1 1 mm sterile fertile female

sterile cleistogamous spikelet floret

Enneapogonupper glum e spikelet

florets 1 cm 1

spikelet

Ehrharta

Anthoxanthum

fertile fertile floret floret

sterile sterile sterile sterile floret floret floret floret spikelet florets florets spikelet florets glume

Phalaris Phalaroides Holcus

glume

Group 7 One perfect floret; reduced florets if present above the perfect one; panicle inflorescence, never spicate

1. Glumes absent or rudimentary. 2. Lemma with an awn 1—2 cm long…...……………………………..Brachyelytrum 2. Lemma awnless or with awn <1 cm long. 3. Spikelets perfect. 4. Spikelets 7—10 mm long; plants annual, cultivated..…………………Oryza 4. Spikelets <6 mm long; plants perennial, native...………………….…Leersia 3. Spikelets unisexual. 5. Staminate and pistillate spikelets in different inflorescences, these inconspicuous; leaves 1—4 cm long..……………………………Luziola 5. Staminate and pistillate spikelets in the same inflorescences, these large and conspicuous; leaves >4 cm long. 6. Staminate spikelets pendulous on spreading lower branches, pistillate spikelets appressed on the stiffly erect upper branch.…………Zizania 6. Staminate and pistillate spikelets on same branches; pistillate at the tip, staminate below...…………………………………………..Zizaniopsis 1. Glumes, at least the second, well developed. 7. Glumes and lemmas awnless. 8. Spikelets 5—8 mm long; lemmas with tuft of hair at base ..…………………………………………..………….Calamovilfa 8. Spikelets <5 mm long, or if >5 mm long, then lemmas without a tuft of hairs. 9. Glumes either as long as or longer than lemmas……....Agrostis 9. Glumes, at least the lower, longer than lemmas. 10. Lemmas 3-veined. 11. Veins of lemmas densely pubescent....…..Blepharoneuron 11. Veins of lemmas glabrous or scabrous....…Muhlenbergia 10. Lemmas 1-veined...……………………………..Sporobolus 7. Other couplet on page 53.

palea lemma callus upper lower glume palea lemma glume spikelet sterile Brachyelytrum sterile floret floret Leersia Oryza Luziola

staminate floret pistillate immature mature spikelet floret pistillate florets palea Zizania lemma staminate awn spikelet Ziznaiopsis

achene floret glume palea lemma palea lemma Calamovifa pistillate staminate spikelet spikelet palea lemma Muhlenbergia

lemma palea lemma palea

lemma palea awned Unawned floret floret floret floret upper glume lower spikelet

spikelet glumes glumes glume Sporobolus

Agrostis Blepharoneuron 52

7. Glumes or lemmas awned. 12. Lower glumes usually 2- or 3-awned, upper glumes usually 1-awned; spikelets in pairs, the lower of the pair sterile, the pair Falling together…………….………………………………..Lycurus 12. Lower and upper glumes not as above or spikelets not falling in pairs. 13. Disarticulation below glumes. 14. Spikelets borne on stipes that fall with the spikelets..Polypogon 14. Spikelets borne on pedicels, disarticulation immediately below the glumes. 15. Lemmas awned from the middle; glume bases often fused…………………...……………………...Alopecurus 15. Lemmas awnless or awned from or near the apex; glume bases usually not fused. 16. Glumes usually awned; lemmas usually awnless …………………………………………….....Phleum 16. Glumes usually awnless; lemmas awned. 17. Lemma awns up to 2.5 mm long; strong Perennial…………………………………..Cinna 17. Lemma awns 5—15 mm long or longer; short lived annual……………………………Limnodea 13. Disarticulation above glumes. 18. Lemmas indurate, awned, with well-developed callus, usually enclosing paleas and caryopses ………………………………………….…A 18. Lemmas not indurate or enclosing paleas and Caryopses..………………………………AA

A. Lemmas indurate, awned, with well-developed callus, usually enclosing paleas and caryopsis) 1. Awn of lemmas 3branched, lateral branches rarely short or rudimentary…………….…………………….…………………………….Aristida 1. Awn of lemmas not branched. 2. Paleas sulcate, Longer than lemmas; lemma margins involute, fitting into the palea groove; lemma apices not lobed…..…………………………..Piptochaetiurn 2. Paleas flat, shorter or longer than lemmas; lemma margins convolute or not overlapping; lemma apices often lobed or bifid. 3. Apices of leaf blades sharp and stiff; caryopses often with 3 ribs at maturity; cleistogenes usually present…...…………………………………… Amelichloa 3. Other couplet on page 55

lemma palea Alopecurus

lemma

floret spikelet Polypogon Lycurus palea

glumes lemma rachilla floret stipe floret

1 cm spikelet glume palea Phelum Cinna

glumes lemma floret Limnodea

callus

spikelet palea Amelichloa

floret 1 cm 1 floret floret

glumes glumes Aristida Piptochaetium

3. Apices of leaf blades acute or acuminate, never both sharp and stiff; caryopses without ribs; cleistogenes occasionally present. 4. Lemma margins strongly overlapping their entire length at maturity, bodies usually rough, apices not lobed; paleas ¼ to ½ length of lemmas, veinless, glabrous..………………………………………………………………...Nassella 4. Lemma margins usually not or only slightly overlapping, sometimes strongly overlapping in species with smooth lemmas, bodies usually smooth on lower portion; paleas from ½ to equaling or exceeding length of lemmas, 2-veined at least on lower portion, usually hairs on lemmas. 5. Calluses 1.5—6.0 mm long, sharply pointed; lemma awns 65—500 mm long ..…………………………………………………………………...Hesperostipa 5. Calluses <2 mm long, blunt or sharp-pointed; lemma awns shorter. 6. Florets usually dorsally compressed or terete; paleas as long as or longer than lemmas and similar in texture and pubescence; lemma margins separate their entire length at maturity ...…..……………………Piptatherum 6. Florets usually laterally compressed; paleas usually shorter than lemmas; lemma margins often overlapping for part or all of their length at maturity………………………….……………….…………Achnatherum

AA. (Lemmas not indurate or enclosing paleas and caryopses)

1. Glumes equal, broad, abruptly short-awned from an obtuse apex; lemmas much shorter than glumes, awnless...………………………………………………Phleum 1. Glumes not equal, or if so, not abruptly awned. 2. Upper glumes 4—5 times as long as lemmas; annual with densely contracted, spikelike panicles...……………………………………………………Gastridìum 2. Upper glumes shorter or only slightly longer than lemmas. 3. Lemmas awned from an entire or minutely clefted apex; glumes, at least the lower, usually shorter than lemmas.....…………………………….Muhlenbergia 3. Lemmas awned from the back, base, or distinctly cleft apex; glumes equaling or exceeding length of lemmas. 4. Lemmas firm, awned from near the apex, awn straight or flexuous, 3—4 times as long as the lemma; annual.…………………………………..Apera 4. Lemmas thin, awned from the back or base, awn usually geniculate when long; annual and perennial. 5. Rachillas not prolonged beyond base of floret; paleas absent, minute or subequal to lemmas...…………………………………………….Agrostis 5. Rachillas prolonged beyond base of floret; paleas at least ½ as long as lemmas …..…………………………………………………Lachnagrostis

awn

crown

awn

palea floret floret floret glumes Piptatherum glumes lemma

Nassella lemma callus Hesperostipa

floret palea lemma glumes lemma

spikelet spikelet Achnatherum floret Phleum Gastridium

palea lemma

lemma palea lemma palea awned rachilla unawned floret floret floret anther

floret

spikelet glumes spikelet glumes Agrostis Muhlenbergia Apera Lachnagrostis 56

Group 8 Inflorescence of 1to several unilateral spicate primary branches

1. Glumes with hooked spines………………………………………………..Tragus 1. Glumes without hooked spines. 2. Spikelets with 2 or more perfect florets. 3. Inflorescence branches paired, verticillate, or clustered at the culm apex. 4. Glumes and lemmas awnless...………..…………………………….Eleusine 4. Glumes or lemmas awned. 5. Upper glumes short-awned or mucronate; rachis projecting stiffly beyond Terminal spikelet..………………………………………....Dactyloctenium 5. Upper glumes not awned or mucronate; rachis not extending beyond terminal spikelet. 6. Lower lemma with 3 awn..……………………………………Trichloris 6. Lower lemma with a single awn....………………………..……..Chloris 3. Inflorescence branches distributed along culm axis, seldom more than 1 at each rachis node. 7. Glumes >1 cm long, much longer than lower florets; lemmas long, ciliate on margins...……………………………………...Trichoneura 7. Glumes <1 cm long, 1 or both much shorter than lowermost florets; lemmas glabrous or puberulent on margins 8. Lemmas 3-veined. 9. Lemmas glabrous, acute, and awnless at apex; spikelets widely spaced and not overlapping, on stiffly spreading branches ..………………………………………….………….Eragrostis 9. Lemmas glabrous or puberulent on veins or at base, usually awned or mucronate; spikelets closely spaced and overlapping when lemmas glabrous or unawned………….…...…Leptochloa 8. Other couplet on page 59. 2. Other couplet on page 59.

spikelet palea

floret

1cm floret

lower upper floret glume glume spikelet glume glume Tragus spikelet Eleusine Dactyloctenium

Chloris florets

glumes spikelet florets Trichoneura

glume palea lemma glumes palea lemma Trichloris palea caryopsis

rachilla

floret upper lower glume glume spikelet Leptochloa spikelet Eragrostis

8. Lemmas 5- or more-veined. 10. Plants perennial, with tall culms and slender, flexuous inflorescence Branches…...………………………………………………………...Glyceria 10. Plants annual, with short, tufted culms and short, stiff inflorescence branches. 11. Spikelets 3-flowered, disarticulation below glumes….……..……….Sclerochloa 11. Spikelets >3-flowered; disarticulation above glumes…….………..Desmazeria 2. Spikelets with 1 perfect floret. 12. Spikelets on main axis as well as on branches. 13. Glumes absent……..……………………………………………..Leersia 13. Glumes, at least the upper, present. 14. Lemmas awned……..………………………….………....Gymnopogon 14. Lemmas awnless. 15. Glumes stiff, strongly 1-veined……………………...Schedonnardus 15. Glumes soft, veinless…….……………………..……..Willkommia 12. Spikelets all on branches and none on the inflorescence axis, the latter sometimes terminating in a single branch. 16. Inflorescence branches 2 or more, digitate, clustered or in 2 or 3 verticels at culm apex. 17. Reduced floret absent or a minute scale; spike-lets Awnless..………………………………………...... Cynodon 17. Reduced floret or florets present above the perfect one; spike lets usually awned. 18. Lowest lemma 3-awned...………………..…….Trichloris 18. Other couplet on page 61. 16. Other couplet on page 61.

1 mm Sclerochloa

palea lemma

palea 2 2 mm glumes spikelet ventral upper lemma view glume rachilla Glyceria lower floret glume spikelet pedicel Desmazeria

palea lemma spikelet

Leersia Schedonnardus

floret spikelet Gymnopogon

florets

spikelet

Wilkommia Cynodon glumes Trichloris 60

18. Lowest lemma with a single awn. 19. Spikelets dorsally compressed….………….………………….…Enteropogon 19. Spikelets laterally compressed or terete. 20. Upper glumes truncate or bilobed…….………….……………Eustachys 20. Upper glumes acute or acuminate……..……………………..…...Chloris 16. Inflorescence 1 to several branches, not digitate, clustered or in verticels. 21. Inflorescence with a single, stout, curved, unilateral branch; upper glume with a short, stout, dorsal awn….……………….…...Ctenium 21. Inflorescence with 1to several branches; upper glume awnless. 22. Spikelets without reduced florets……………………….Spartina 22. Spikelets with 1 or staminate or reduced florets above the perfect ones. 23. Spikelets in deciduous clusters of 3, middle spikelet perfect, lower 2 staminate..……….…………..…Cathestecum 23. Spikelet not in clusters of 3, or if so, the lower 2 not staminate or sterile. 24. Panicle branches deciduous, disarticulation occurring at their bases; spikelets usually 1—l30 per branch, usually appressed rather than pectinate.…Bouteioua 24. Panicle branches persistent; disarticulation above the glumes, spike-lets 6—130 per branch, pectinate …...…………………...………………...Chondrosum

florets florets

second sterile glumes lemma floret Eustachys glumes bisexual Chloris floret

glumes Enteropogon Cathestecum

lower upper glume glume

Spartina Ctenium distal inflorescence branch spikelet floret

upper lemma

glumes florets

glume lower floret inflorescence branch glumes Bouteloua Chondrosum

Group 9

Inflorescence a terminal, bilateral spike or spicate raceme3

1. Spikelets in capitate clusters, these subsessile in leafy portion of plant; lemmas 3- veined; lower tufted or sod-forming grasses. 2. Disarticulation below glumes, spikelets falling in burlike clusters; plants strongly stoloniferous...………………………………………………...………….Buchloë 2. Disarticulation above glumes, spikelets not falling in clusters. 3. Lemmas with 3 stout, ciliate awns...……………….…………….Blepharidachne 3. Lemmas with a single awn. 4. Glumes much longer than lemmas; lemmas deeply bifid at apex.....Dasyochloa 4. Glumes shorter than lemmas; lemmas acuminate at apex, not bifid ……………………………………………………………………...Munroa 1. Spikelets not in capitate clusters, or if so, these elevated above basal clump of leaves. 5. Spikelets with 1 floret. 6. Spikelets single at each node. 7. Plants annual. 8. Glumes both present on all spikelets.……….………….Parapholis 8. Glumes both present only on terminal spikelet, lower glume lacking on all other spikelets..……………………….….Hainardia 7. Plants perennial. 9. Margins of lemmas ciliate; inflorescence a slender, curved, unilateral spike...……………………………..………………….Microchloa 9. Margins of lemmas glabrous. 10. Spikelets partially embedded in a thick, flattened rachis; plants with stout stolons.…...………………….Stenotaphrum4 10. Spikelets sessile or short-pediceled on a slender rachis..Zoysia 6. Spikelets 3 at each node. 11. Lateral spikelets pediceled and sterile ……….….Critesion 11. Lateral spikelets sessile and perfect...……….….Hordeum 5. Other couplet on page 66.

3 Misinterpretation of panicles with disarticulating branches (e.g., Chondrosum, Hilaria, Pleuraphis) or greatly reduced panicles (e.g., Phleum, Alopecurus) could erroneously lead one to this group. 4 Stenotaphrum is a member of the Paniceae, and the spikelet characters would key it out in Group 5. It is included here because the inflorescence is easily interpreted as a spike, and one might immediately come to Group 9 without close examination of the spikelet. If the specimen does not match any of the genera within this section, perhaps look at gen ,m a within the Andropogoneae (Group 4) that have spikelets embedded in a thickened rachis (e.g., Hackelochloa, Rottboellia, Ercrnochloa Coelorachis).

pistillate rudimentary third floret glume fourth floret glume floret Buchloë sterile spikelet second staminate Dasyochloa first floret floret upper Blepharidachne glume spikelet spikelet floret

glumes glumes Munroa glumes

upper first glume rachis spikelet internode Parapholis spikelet lower upper lemma glume Hainardia upper glume

lower lemma spikelet spikelet glume glumes Microchloa Stenotaphrum Zoysia central spikelet lateral lateral spikelet spikelet

Hordeum

Lemma of central spikelet glumes of central spikelet Critesion 64

5. Spikelets with 2 or more florets. 12. Spikelets oriented edgewise to rachis, lower glumes absent except on terminal Spikelets.…………………………………………………………...……Lolium 12. Spikelets not oriented edgewise to rachis; lower glumes present on all spikelets. 13. Upper glume bearing a stout, divergent awn on the back..……….…Ctenium 13. Upper glume not bearing a dorsal awn. 14. Annuals or biennials; introduced, cultivated cereal or weed. 15. Glumes ovate with 3 or more veins at midlength. 16. Spikelet sunken or embedded in rachis; spike narrow, <5 mm wide; rachis disarticulating at maturity..………………..….Aegilops 16. Spikelets not sunken into rachis; spike thick,>5 mm wide; rachis not disarticulating at maturity…………………...….Triticum 15. Glumes subulate to lanceolate with only 1 vein at midlength..….Secale 14. Perennial; native or introduced. 17. Spikelets solitary at all, or almost all, rachis nodes…………..A 17. Spikelets 2—7 at all, or most, rachis nodes……..…………AA

A Spikelets solitary at all, or almost all, rachis nodes 1. Lemmas thin, awnless, distinctly 3-veined. 2. Spikelets 1.5—3.0 cm long, staminate; stoloniferous perennial……...…Scleropogon 2. Spikelets <1 cm long. 3. Lemmas awnless; spikelets unisexual, stoloniferous annual...…Eragrostis reptans 3. Lemmas with delicate awn; spikelets perfect; cespitose perennial...... ….Tripogon 1. Lemmas thick or less frequently thin, 5- to several-veined; veins faint or distinct. 4. Spikelets short-pediceled; thus, inflorescence a spicate raceme. 5. Lemmas awnless. 5. Other couplet on page 68. 4. Other couplet on page 68.

rachis internode

glume

glume spikelet glume fertile rachis Ctenium spikelet Aegilops Lolium

glume glume spikelet

Triticum lemma

pistillate spikelet floret Secale Scleropogon

lemma palea Staminate culm

palea Tripogon staminate floret Eragrostis

lower upper glume glume spikelet

6. Disarticulation below the glumes; upper leaf sheaths enlarged and partially enclosing inflorescence...……………………………………………Sclerochloa 6. Disarticulation above the glumes; upper leaf sheaths not enlarged.…Desmazeria 5. Lemmas awned. 7. Glumes much longer than lemmas; lemmas with geniculate awn from a bifid apex……………..………………………………………….Danthonia 7. Glumes not longer than lemmas; lemmas with a straight awn form an entire apex..……………………………………………………………..Trachynia 4. Spikelets sessile; thus, inflorescence a spike. 8. Rachis internodes <5 mm long; spikelets closely imbricate, more than 3 times the length of rachis internodes, diverging...……………....Agropyron 8. Rachis internodes >5 mm long; spikelets appressed or ascending, 1—3 times the length of rachis internodes. 9. Glumes subulate to narrowly lanceolate, stiff, 1- or rarely 3-veined at midlength. 10. Glumes lanceolate, tapering to an acuminate tip, slightly curved to one side at apex 10. Glumes subulate from near the base, straight...…………….Leymus 9. Glumes usually ovate, rectangular, or lanceolate, narrowing above midrib; (1—) 3—5(—7)-veined at midlength. 11. Glumes stiff, truncate, obtuse, or acute, unawned; glume keels smooth below, scabrous above...…………………..Thinopyrum 11. Glumes flexible, acute to acuminate, sometimes awn-tipped; keels usually uniformly smooth or scabrous. 12. Spikelets distant, scarcely reaching base of spikelet above on same side of rachis ……………………...Pseudoroegneria 12. Spikelets closely spaced, usually reaching at least the midlength of spikelet above on same side of rachis....….Elymus

AA (Spikelets 2—7 at all, or most, rachis nodes)

1. Glumes 4—18 mm long, subulate to narrowly lanceolate, 0- to 1-veined at midlength; blades usually with closely spaced, equally prominent veins on adaxial surface. 2. Disarticulation in the spikelet, beneath each floret; sometimes cespitose, often rhizomatous; ligules 0.3—8.0 mm long...…………………………………Leymus 2. Disarticulation tardy, in rachises; plants cespitose, not rhizomatous; ligules 0.2- 0.3 mm long.………………………………………………………Psathyrostachys 1. Glumes flat and with 3 veins at midlength or, if subulate and 1veined, <4mm long or >18 mm Long; blades widely spaced. unequally prominent veins on adaxial surface………………………………………………………………………Elymus 67

1 cm

palea upper glume rachilla lemma lower floret floret glume spikelet Desmazeria spikelet pedicel Danthonia Sclerochloa

glume glume spikelet lemma Trachynia spikelet Agropyron

Thinopyrum spikelet

lower upper glumes node glume floret spikelets glume

Leymus spikelet Pascopyrum

node 1 cm 1 lemma spikelets glume glume spikelet spikelet Psathyrostachys spikelet Elymus Pseudoroegneria 68

Group 10 2 or more fertile florets per spikelet; inflorescence an open or contracted panicle or raceme with spikelets on well-developed pedicels

1. Plants 2—6m tall. 2. Spikelets mostly 3—7 cm long with 7—13 florets...………………...... Arundinaria 2. Spikelets <2 cm long and with fewer than 7 florets. 3. Leaves mostly basal, forming large, distinct clumps; without creeping rhizomes; blades 0.5—1.5 cm broad; ornamental, rarely escaping.…...Cortaderia 3. Leaves evenly distributed; culms with creeping rhizomes forming large colonies; blades 2—6 cm broad. 4. Lemmas villous; rachilla glabrous…...….…………………..………...Arundo 4. Lemmas glabrous, rachilla villous………………………..………..Phragmites 1. Plants <2 m tall. 5. Lemmas with 3, usually conspicuous, veins...…………………………..A 5. Lemmas with 5—15, conspicuous or obscure, veins....……………….AA

A (Lemmas with 3, usually conspicuous, veins)

1. Lemma veins pubescent or puberulent, or base of lemma long-hairy. 2. Plants rhizomatous; lemma veins glabrous, with tuft of hair at base....…..Redfieldia 2. Plants not rhizomatous; lemmas pubescent or puberulent on veins, at least below. 3. Paleas densely long-ciliate on upper half…………………………..…..Triplasis 3. Paleas not densely long-ciliate. 4. Lemma veins each extending into an awn………………………….Triplasis 4. Lemma veins not extending into awns. 5. Lemma veins conspicuously long-hairy, at least below....……...... Erioneuron 5. Lemma veins inconspicuously puberulent...………………….….....Tridens 1. Lemma veins not pubescent, base not long-hairy. 6. Lemmas 3-awned. 7. Lemma awns 4—10 cm long...…………………………....Scleropogon 7. Lemma awns <1 cm long...……………………………Blepharidachne 6. Lemma awnlcss.

lower Arundinaria glume upper sterile spikelet glume spikelet florets Arundo Cortaderia

upper Phragmites glume lower glume Triplasis

floret lemma Redfieldia spikelet Tridens palea lemma rachilla floret upper lower glume glume

pistillate floret spikelet rudimentary third floret florets Erioneuron fourth floret

glumes sterile staminate second Triraphis Scleropogon first floret floret

70 pistillate Blepharidachne spikelet floret

8. Caryopses large, turgid, and beaked...... ……………………………………Diarrhena 8. Caryopses not large, turgid, and beaked...…………………………………Eragrostis

AA (Lemmas with 5—15, conspicuous or obscure veins)

1. Lemmas awned. 2. Lemmas with more than 5 awns. 3. Glumes 1-veined, florets falling together..……………………...…Pappophorum 3. Glumes 5- to many-veined, florets falling separately...…………………...Cottea 2. Lemmas with a single awn. 4. Culms woody, perennial; spikelets 3—7 cm long...…….………...Arundinaria 4. Culms not woody or perennial; spikelets rarely as long as 3 cm. 5. Glumes U (02cm long; lemmas 1.5cm long or longer; introduced annual ……...…………………………………………………………..….Avena 5. Glumes <2cm long, or if longer, lemmas <1.5cm long. 6. Lemmas awned from about halfway down back...………………...Aira 6. Lemmas awned from a bifid or entire apex. 7. Lower glumes longer than lowermost floret; lemmas awned from a bifid apex. 8. Awns 5—15 mm long or longer; usually flattened at base …………………………………………………………Danthonia 8. Awns up to 2 mm long: not flattened at base...…………...Schismus 7. Lower glumes about as long as or shorter than lowermost florets. 9. Spikelets of 2 kinds, fertile and sterile; fertile spikelets sessile and nearly covered by sterile spikelets in a spicate or subcapitate panicle...……………………………………………...Cynosurus 9. Spikelets not as above. 10. Paleas adherent to caryopses; lemmas usually awned from a bifid or bibbed apex; veins converging distally; ovary apices hairy...……………………………………………………B 10. Paleas not adherent to caryopses; lemmas not both bifid or bibbed and with convergent veins; ovary apices usually glabrous……………………………………………...….BB 1. Other couplet on page 75

lemma palea palea

caryopsis floret

upper lower glume upper lower glume glumes glume glume spikelet spikelet Eragrostis Pappophorum Diarrhena

glume glume spikelet floret spikelet floret with spikelet awned lemma Cottea Avena Aira

glume

glume floret glume

glume glume fertile spikelet glume spikelet Danthonia spikelet pair spikelet Cynosurus Schismus

B Paleas adherent to caryopsis 1. Lemmas strongly keeled; spikelets strongly laterally compressed...……….Ceratochloa 1. Lemmas rounded over midrib; spikelets terete to elliptical. 2. Awn arising <1.5 mm below lemma apices. 3. Lower glumes 1—3-veined; upper glumes 3—5-veined; perennial, or if annual, lower glumes 1-veined and upper glumes 3-veined...…………...……Bromopsis 3. Lower glumes 3—5-veined; upper glumes 5—9-veined; annual and biennial ...………………...…………………………………………………….Bromus 2. Awn arising >1.5 mm or more below the lemma apices. 4. Lemma apices bifid, teeth 1—5 mm long..……………………….Anisantha 4. Lemma apices entire or bifid, teeth <1 mm long…………………….Bromus

BB (Palea not adherent to caryopsis) 1. Lower glumes with 3—5 distinct veins; glumes and lemmas rounded on back. 2. Lower glumes 1-veined; disarticulation always above the glumes; lemmas never with hairs >1 mm long; culms never with bulbous bases; upper florets sometimes reduced but not forming a morphologically distinct rudiment; plants of wet habitats…….……………………………………………………...Glyceria 2. Lower glumes 1—9-veined; disarticulation above and below glumes; sometimes with hairs >1 mm long; upper florets often reduced to form a morphologically distinct rudiment; culms sometimes with bulbous base; plants of drier, well- drained habitats..……………………………………….………………….Melica 1. Lower glumes with 1—3 distinct or indistinct veins; glumes and lemmas keeled or rounded on back. 3. Paleas colorless. 4. Upper glumes obovate, broadest above midlength; disarticulation below glumes...…………………………………………………….….Sphenopholis 4. Upper glumes broadest below middle; disarticulation above glumes. 5. Plants perennial; palea veins not extending into short awns...... ….Koeleria 5. Plants annual; palea veins extending into short awns..………….Rostraria 3. Paleas green or brown, at least on veins.

lemma

Bromus upper lower glume glume

upper lower spikelet glume glume

spikelet spikelet Ceratochloa Bromopsis

lemma rudiment

floret Upper palea lemma Upper glume floret spikelet glume spikelet spikelet Glyceria Melica Anisantha

distal floret 1 mm upper glume florets florets

glumes glumes glumes

Sphenopholis Koeleria Rostraria 74

6. Lemmas awned from a distinctly bifid apex, awn straight or geniculate; upper glumes equaling or exceeding length of lowest floret. 7. Plants perennial; disarticulation above glumes………...…………………Trisetum 7. Plants annual; disarticulation below glumes...………………………...Sphenopholis 6. Lemmas awned from an entire or minutely notched apex, awn straight; upper glumes usually shorter than lowest floret. 8. Spikelets laterally compressed, asymmetrical, subsessile in dense clusters at apices of stiff, erect, or spreading branches; glumes and lemmas acute or irregularly short-awned; perennial...……………………………………Dactylis 8. Spikelets not laterally compressed or asymmetrical, not in dense clusters at branch apices. 9. Plants perennial...……………………………………………………Festuca 9. Plants annual...………………………………………………………Vulpia 1. Lemmas awnless. 11. Lemma veins strongly and uniformly developed and equally spaced; sheath margins connate, at least below………………………….Glyceria 11. Lemma veins not strongly and uniformly developed, or if so not equally spaced. 12. Glumes and lemmas spreading at nearly right angles to rachilla, inflated and papery; spikelets on slender pedicels..……………Briza 12. Glumes and lemmas not as above. 13. Lower glumes distinctly longer than lowest florets...……Schismus 13. Lower glumes equaling or shorter than lowest florets. 14. Lowermost 1—3 florets reduced, sterile, about 1/2 as long as those above. 15. Disarticulation below glumes, spikelets falling entire; plants of coastal dunes...…………………………..Uniola 15. Other couplet on page 77. 14. Other couplet on page 77.

distal floret

lower floret Trisetum spikelet floret spikelet glume Dactylis Sphenopholis floret

floret

floret Vulpia Glyceria Festuca spikelet spikelet spikelet

florets florets fertile florets

glume glume

glume glume glume Briza glume spikelet

spikelet Uniola SSchismus

15. Disarticulation above glumes and between florets; plants of woodland sites ...……..…………...………………………………………..…….Chasmanthium 14. Lowest florets not reduced, as large as or larger than those above. 16. Paleas colorless; lateral lemma veins indistinct. 17. Upper glumes obovate, broadest above mid-length; disarticulation below glumes...…………………………………………….Sphenopholis 17. Upper glumes broadest below middle; disarticulation above glumes ...………………………………………………………...….….Koeleria 16. Paleas green or brown, at least on the veins. 18. Lemmas 7—13-veined...………………………………………….C 18. Lemmas 3—S-veined…...…………………………………..…...CC

C. Lemmas 7—13-veined 1. Spikelets unisexual, staminate and pistillate in separate inflorescences and usually on separate plants (dioecious); glumes and lemmas thick, firm, indistinctly veined. 2. Plants with stolons, lacking rhizomes...……………………..……………Allolepis 2. Plants with rhizomes, lacking stolons…………...……………………….Distichlis 1. Spikelets perfect; glumes and lemmas thin, lemma mostly with membranous margins. 3. Sheath margins united at or near base; caryopsis without 2 hornlike styles. 4. Paleas adherent to caryopses. 5. Lemmas strongly keeled; spikelets strongly laterally compressed ……………………………………………………………….Ceratochloa 5. Lemmas rounded over midrib; spikelets terete to slightly laterally compressed. 6. Awn arising <1.5 mm below lemma apices. 7. Lower glumes 1—3-veined; upper glumes 3—5-veined; perennial, or if annual, lower glumes 1-veined and upper glumes 3-veined …………………………………………………………Bromopsis 7. Lower glumes 3—5-veined; upper glumes 5—9-veined; annual and Perennial...………………………………………………….Bromus 6. Awn arising 1.5 mm or more below the lemma apices. 8. Lemma apices bifid, teeth 1—5 mm long...………...…Anisantha 8. Lemma apices entire or bifid, teeth <1 mm long...... …….Bromus 4. Other couplet on page 79. 3. Other couplet on page 79.

palea lemma

Chasmanthium distal floret lower floret floret florets

Koeleria glumes glumes sterile floret Sphenopholis glume glume

spikelet

lemma

pistillate floret

pistillate staminate floret spikelet staminate staminate Distichlis spikelet inflorescence spikelet Allolepis Ceratochloa

Anisantha

lemma lower upper upper glume glume lower glume spikelet glume Upper Bromus glume

Bromopsis Upper 78glume

ume ume ume

4. Paleas not adherent to caryopses...…………………………………………...Melica 3. Sheath margins free to base; caryopses suborbicular, with persistent hornlike styles……………...…………………………………………………..Vaseyochloa

CC. (Lemmas 5-veined, rarely 3-veined) 1. Lemmas thick, veins converging at apex to form a stout beak...…………...Diarrhena 1. Lemmas thin and/or firm, but not thick, veins not converging to form a beak. 2. Lemma apices narrowly acute or attenuate, margins not scarious, usually short- awned. 3. Leaves without auricles...……………………………………………….Festuca 3. Leaves with auricles...……………………………………………Schedonnardus 2. Lemma apices broadly acute to obtuse, margins usually not scarious……………………………………………………...……………….Poa

Vaseyochloa Diarrhena spikelet lemma rudiment Caryopsis

palea upper glume lower glume Melica lower glume spikelet upper glume spikelet

lemma spikelet anthers floret florets

spikelet glumes spikelet palea lemma Schedonnardus Festuca Poa

References

Grass structure Illustration: The grasses and grass-like plants of New Mexico / E.O. Wooton and Paul C. Standley. Agricultural College, N.M. New Mexico College of Agriculture and Mechanic Arts, Agricultural Experiment Station, 1912.

Glossary: http://botany.csdl.tamu.edu/FLORA/taes/tracy/610/. S.M. Tracey Herbarium. University of Texas A&M. College Station, Texas

Guide to Texas Grasses. Robert B. Shaw. Texas A&M Nature Guides. Texas A&M University Press.

Illustrated Flora of East Texas Vol. 1. George M. Diggs Jr., Barney L. Lipscomb, Monique D. Reed, Robert J. O’Kennon. Botanical Research Institutes of Texas & Austin College.

All photos not referenced from the literature are curtesy of Wikimedia Commons. https://commons.wikimedia.org/wiki/Main_Page

Glossary 81

A - Prefix meaning without. Abaxial - Located on the side away from the axis. Achene - One-seeded, dry indehiscent fruit with a relatively thin wall in which the seed coat is not fused to the ovary wall. Acuminate - Gradually tapering to a sharp point; point is drawn out. Acute - Sharply pointed, but less tapering than acuminate; angle 90o or less. Adaxial - Located on the side nearest the axis. Adhere - To stick to. Adherent - Sticking or clinging. Adnate - Fusion of unlike parts (e.g., fusion of palea to the caryopsis in Bromus). Adventitious roots - Roots developing from basal culms, nodes, or some structure other than the seed. Adventive - A term used to denote an exotic species that has become established from chance or accidental seeding. Aggregate - Clustered or forming a group with objects in close proximity. Alternate - Located singly at each node. An arrangement of parts, e.g. leaves, placed at different heights along an axis. Annual - Completing life cycle from seed to maturity to death within one year or one season. Anther - Pollen bearing portion of the stamen. Antrorse - Directed upward or forward toward the apex; the opposite of retrorse. Apex - Uppermost tip of a structure. Apices - Plural of apex. Apical - Located at the tip. Apiculate - Ending in a short, flexible point. Appendage - A secondary part or a projecting part. Appressed - Lying against an organ in the direction of the apex. Aristate - Provided with a short awn or bristle from the apex, edge or back of an organ. Aromatic - Having an odor, fragrant or otherwise; bearing volatile essential oils. Articulate - Jointed; a node for natural separation. Ascending - Sloping or rising obliquely upward. Asexual - Without sex; sexless; not involving gametes. Asymmetrical - Not having planes which divide the structure into mirror-image halves. Attenuate - Gradually narrowing to a pointed apex or base; sharper than acute. Auricle - A finger-like appendage or flange of tissue at the junction of the blade and 82 sheath in some grasses. Holds the open sheath to the culm. Autumnal - Growth form for late summer and fall (e.g. Dichanthelium). Awn - The extension of the vein (nerve) of spikelet bracts beyond the leaf-like tissue. Axil - The upper angle between an organ (branch) and its axis. Axillary - Occurring in an axil. Axis - The central stem(s) of an inflorescence, particularly of a panicle. Barbed - Retrorse projections or hairs. Basal - Referring to the base or located there; the lower portion of a structure. Bearded - Bearing long, stiff hairs, e.g. at culm nodes of Dichanthium. Bi - Two. Bifid - Apex with one cleft or having two teeth. Bilateral - Two sided; structures on two sides of an organ. Binomial - A taxonomic name consisting of a genus name and a specific epithet forming the species name. Blade - Part of the leaf above the sheath. Bloom - A waxy covering on surfaces, such as fruits and leaves; usually results in a bluish color. Bract - A modified leaf, often scale-like (e.g. glumes, lemmas, paleas). Branch - A lateral stem or part of the panicle inflorescence. Bristle - A stiff, slender hair or appendage likened to a hog's bristle; in Setaria, Pennisetum and a few other grasses, it is a highly reduced branch without a spikelet at the apex. Bud - An undeveloped stem, branch, leaf, or flower. Bulb - A subterranean bud with fleshy scales, such as those of an onion. Bulliform Cell - usually large, thin-walled, highly vacuolated, colorless epidermal cells present in intercostal zones of the leaf blade. Bur - A rough or prickly covering surrounding the fruits or spikelets of some genera. Caespitose (cespitose) - Tufted; several or many stems in a close tuft. Callus - The indurate downward extension of the mature lemma in Stipa, Aristida, and some other genera. Capillary - Very slender or hair-like. Capitate - In a globular cluster or head. Capitellate - Possessing a minute swelling at the apex. Cartilaginous - Firm and tough, but flexible; like cartilage. Caryopsis - One-seeded, dry, indehiscent fruit or grain of grasses with a lateral embryo. The seed coat is adnate to the pericarp. Cauline - Belonging to the stem, such as stem leaves. Central axis - The main axis of the inflorescence. 83

Central groove - A longitudinal depression in the sides of the pedicels of Bothriochloa. Cespitose - See caespitose. Chlorenchyma - Parenchyma cells containing chloroplasts. Ciliate - Fringed with hairs on the margin. Ciliolate - Minutely ciliate. Clasping - To hold parts together; holding. Cleistogamous - Applied to flowers or florets fertilized without opening; must be self-fertile. Cluster - A number of similar things, e.g. bracts or spikelets, grouped together. Coleoptile - A protective sheath for the young shoot in the embryo. Coleorhiza - The sheath of the monocotyledonous embryo that protects the primary root or radicle. Collar - The area on the outer (abaxial) side of a leaf at the junction of the sheath and blade. Column - The lower, undivided part of the awns of certain Aristida species. Compact - Short and dense. Compressed - Flattened strongly, typically laterally; keeled. Concave - Dished inward, an existing hollow. Connate - Fusion of like parts, such as sheath margins to form a tube. Continuous - A rachis or other organ that does not disarticulate. Contracted - Narrow or dense inflorescences, the branches being appressed or short. Convex - Rounded on the surface. Cordate - The heart-shaped base and pointed apex of a structure e.g. a leaf blade. Coriaceous - Leathery texture. Cork Cell - In the epidermis of grasses, a short cell that contains suberin (an inert impermeable waxy substance present in the cell walls of corky tissues) in its walls. Corm - Short, bulb-like stem. Crisp - Undulating in a horizontal plane. Crown - Persistent base of a perennial. Culm - The jointed grass stem composed of nodes, internodes, leaves, and axillary buds. Cylindrical - Shaped like a tube, round in cross section with parallel margins. Deciduous - Not persisting, falling away in less than one year. Decumbent - Curved upward from a horizontal or inclined base, e.g. stems. Deflexed - Turned downward abruptly. Deltoid - Triangular in outline; shaped like the Greek letter delta. Dense - Inflorescences having crowded spikelets. 84

Depauperate - Stunted. Dermal - Having to do with the epidermis. Dichotomous Key - A tool used in the identification of unknown plants by stating the conspicuous features by which the various taxa can be recognized. Two contrasting choices are presented at each step. One choice in the couplet is accepted and the other rejected, weaving a path to the indentity of the plant. Diffuse - Open and much branched, widely spread. Digitate - Parts (three or more) arising from the summit of a structure (e.g., branches of the Chloris inflorescence). Dilated - Expanded, enlarged, or wider. Dioecious - Unisexual, the staminate and pistillate flowers being on separate plants. Diploid - Having two complements or sets of haploid chromosomes. Disarticulate (disarticulation) - Separating at the nodes (joints) naturally at maturity. Discoid - Resembling a disk or platter. Distichous - Obviously 2-ranked and appearing as the rungs of a ladder. Divergent - Extending away from each other by degrees. Dorsal - Relating to the back of an organ, away from the axis; abaxial surface. Elliptic - Arching margins of leaf which is pointed at both ends, about two times longer than wide. Elongate - Narrow, the length several times the width or thickness. Emarginate - Slightly notched apex. Embryo - The young plant that is present in a seed before germination. Embedded - Appearing or growing as part of another structure. Endosperm - Nutritive tissue near the embryo of the seed; develops from a fusion of polar nuclei and sperm nucleus. Entire - A continuous margin without teeth or lobes. Epiblast - A small, nonvasculated flap or flange of tissue on the side of the grass embryo axis opposite the scutellum. Equal - Same length or width. Erect - Upright in relation to the ground; perpendicular to the ground. Erose - Irregularly toothed on the margins or at the apex; appearing to be chewed off. Exserted - Protruding (e.g., the inflorescence from the sheath). Fascicle - Small bundle or cluster. Fertile - Capable of producing a fruit or caryopsis. Fibrous - Looking like a mass of fiber; thread-like but may appear branched. Filiform - Thread-like; long and narrow. First glume - The lowermost glume, odd-veined, an empty bract. 85

Flabellate - Broadly wedge or fan-shaped. Flexuous - Bent gradually in one direction and then another. Floral axis - The structure that the palea and flower are attached to the rachilla. Floret - The lemma, floral axis, and palea with the included flower (pistil, stamen, and lodicules) or Caryopsis (floret with all parts). Flower - The reproductive axis of angiosperms consisting of sepals, petals, stamens, and carpels, although one or more of these may be absent. Flowering - Producing the male and female reproductive structures. Fruit - Ripened ovary. Fusiform - Spindle-shaped; widest near the middle and tapering in toward both ends. Geniculate - Bent sharply, like a bent knee. Genus - An inclusive, taxonomic category whose species have more characteristics in common with each other than with species of other genera within the same family. Gibbous - Swollen on one side; see the second glume of Sacciolepis. Glabrate - Almost glabrous. Glabrescent - Becoming glabrous (without hairs) as that plant structure ages or matures. Glabrous - Without hairs of any type. Glandular - Bearing glands. Glaucous - A waxy bloom or white covering of a surface. In plants the result is usually a blue-green color. Globose - Round or spherical. Glumes - The pair of bracts at the base of the spikelet, odd-veined, empty bracts that may be awned or awnless. Grass Flower - The reproductive axis subtended by the palea and lemma and consisting of lodicules, stamens, and carpels, although it may also be unisexual. Habit - General appearance or aspect of a plant; growth form. Herbaceous - Having the character of an herb; not woody. Grasses, grasslike, and forbs are herbs. Habit - General appearance or aspect of a plant; growth form. Herbaceous - Having the character of an herb; not woody. Grasses, grasslike, and forbs are herbs. Herbarium Specimen - Dried and pressed plants mounted for permanent preservation with collection data such as habitat and geographical location included. Hirsute - Covered with coarse, straight rather stiff hairs, usually perpendicular to the surface. Hispid - Rough with erect, bristly hairs. Hyaline - Thin and translucent or transparent. 86

Identification - An Act or instance of identifying. Imbricate - Overlapping, as do shingles on a roof. Imperfect - Having unisexual flowers. Having either stamen or pistil (carpels) but not both. Inconspicuous - Hard to see; not striking to the eye. Indehiscent - Not opening at maturity, staying closed. Indurate - Hard. Infertile - Incapable of sexual reproduction. Inflated - Puffed up, bladdery. Inflorescence - Flowering part of a plant, above the uppermost leaf or portion thereof. Inrolled - Having margin rolled toward the midvein; involute. Intercalary Meristem - Meristematic tissue occurring in an area other than at the apical meristem; tissue at the base of the internode in young culms. International Code of Botanical Nomenclature - The documentation containing the rules that governs the assignments of names to plants. The ultimate goal, being to provide a single correct name for each taxon. Internode - The part of a culm between two successive nodes. Involucre - A cluster of bristles or sterile branchlets below the spikelets (e.g., Cenchrus and Pennisetum). Involute - Rolled inward from the edges so that the upper surface is within Joint - The node of a grass culm, spikelet, inflorescence, or any other node. Keel - The sharp fold at the back of a compressed sheath, glume, lemma, palea, or caryopsis. Lacerate - Appearing torn on the margin; irregularly cleft. Lanate - Woolly covering of short dense hair. Lanceolate - Shape or outline like the head of a spear; pointed at both ends and widest below the middle. Lateral - Referring to the sides. Leaf - The lateral organ of a grass culm, typically consisting of a sheath, blade, ligule, and auricles. Leaf blade - The expanded and flattened portion of a leaf. Leaf sheath - The tubular basal portion of a leaf that encloses the stem, as in grasses and sedges. Lemma - An odd-veined bract of a spikelet occurring above the glumes; the abaxial bract of the floret that may be awned or awnless. Ligule - The adaxial appendage, membrane, ciliate membrane, or ring of hairs on the

87 inside of a leaf at the junction of sheath and blade. Linear - Long and narrow with parallel margins. Lobed - A projecting portion of an organ in which the divisions are less than half the distance to the base or midrib; usually rounded at apex. Lodicules - Two or three membranous parts at the base of the grass flower; thought to be reduced perianth. Longevity - Life span of an organism; in plants annual, biennial or perennial. Margins - The edges (e.g. the leaf edge or margins). Mat-forming - A low growth form appearing like a pad. Membranous - Thin, soft, pliable. Meristem - Undifferentiated cell capable of developing into a number of organs and/or tissues; a growing point. Mesic - Characterized by having a medium moisture supply e.g., a type of habitat or soil. Midrib - Central vein of a leaf or leaflet. Midvein - The central vein or vascular bundle of a leaf, lemma, glume, or similar structure. Minute - Very small. Monocotyledons - Having one cotyledon or seed leaf. Monoecious - Having staminate and pistillate flowers on the same plant but each sex on different flowers. Motte - Small grove or clump of trees. Mucro - A minute awn or excurrent midvein of an organ (e.g., on a lemma). Mucronate - Tipped with a short tip or point like an awn. Usually the short extension of a vein beyond the leafy tissue. Muticous - Blunt, or without a definite point. Neuter - Without sexual structures; not having stamens or pistils. Node - The joint of a culm, inflorescence, or spikelet. Nomenclature - The aspect of taxonomy concerned with the orderly application of names to taxa in with the International Code of Botanical Nomenclature. Ob- Prefix meaning inversely. Obconic - A solid figure with the shape of a cone; widest at the apex and pointed at the base. Oblique - Unequal sides; slanting. Oblong - Object with round ends and parallel margins, three times longer than wide. Obovate - Egg-shaped with widest part above the middle. Obovoid - A solid that is obovate in outline.

Obpyriform - Pear-shaped, with the wide end toward the apex. Obtuse - Pointed with an angle greater than 90o. A broad pointed apex or base. One-sided - Secund; arranged only on one side. Open - Loose, spreading (e.g., inflorescences, with few spikelets and long branches). Opposite - Structures that are paired at the nodes and placed one on each side of the node; stamen inserted directly in front of the petal; leaves are also opposite. Orbicular - Approaching a circular outline. Oval - Broadly elliptical but with rounded ends; similar to oblong, but not as long. Ovate - Egg-shaped with the widest part below the middle Ovulate - Bearing ovules. Ovule - The structure within the ovary that will become the seed after fertilization. Paired - Occurring in two's, e.g. two spikelets per node. Palea - The adaxial bract of a floret; two-veined, arising from the floral axis. Panicle - An inflorescence type in which the central axis branches and rebranches. Papilla - A minute nipple-shaped projection. Papillose - Having minute nipple-shaped projections on the surface. Pectinate - An arrangement of parts resembling the teeth of a comb (e.g., the spikelets on Bouteloua hirsuta). Pedicel - The stalk of a spikelet, except for spikelets on a spike inflorescence. Pedicellate - Having a pedicel or stalk. Peduncle - The stalk or stem of an inflorescence. Pendulous - Drooping, hanging downward, suspended. Perennial - Growing more than 2 years; completing several reproductive cycles. Perfect - Flowers having both stamen and pistils (carpels). Pericarp - The ripened ovary wall after it becomes a fruit. Persistent - Remaining attached, either after other parts have been shed or for a considerable period. Petiole - Stalk of a leaf blade. Pilose - Long, soft hairs that are typically straight. Phytomere - The basic unit of structure of the grass shoot, an internode together with the leaf and portion of the node at the upper end and a bud and portion of the node at the lower end. Pinnate - Having two rows of lateral divisions along the main axis. Pistil - Seed producing structure of a flower with ovary, style and stigma. Pistillate - Applied to spikelets bearing female parts only and to an inflorescence or a plant with female flowers. Pithy - Spongy; e.g., culm of Saccharum.

Pitted (pit) - Marked with small depressions or pits. Plano-convex - Flat on one side and convex on the other. Playa - A dried up lake basin. Plumbeous - Lead-colored. Plumose - Feathery in appearance, having fine hairs on each side. Polyploid - Having the two or more times the basic chromosomal complement. Primary Branch - Any branch arising from the main axis; all branches that come from the central axis of a grass inflorescence. Primary Unilateral Branch - Any branch that originates from the central or main axis of a panicle inflorescence with spikelets along one side or what appears to be one side. Prophyll - First leaf of a lateral branch; a sheath with 2 veins. Prostrate - Lying flat on the ground. Puberulent - Minutely pubescent. Pubescent - Covered with short, soft hairs. Pulvini - A swelling at the base of a leaf or a branch of the inflorescence. Punctate - Covered with glandular dots, pits, or depressions. Pungent - A sharp point; an acrid taste. Pyramidal - Triangular in outline; shaped like a pyramid. Raceme - An inflorescence type in which all the spikelets are pedicellate on the rachis. Racemose - Branches that are like racemes; with some combination of sessile and short pedicellate spikelets. Rachilla - The axis of the spikelet; the structure to which the glumes, lemma and floral axis are attached. Rachis - The axis of a spike, spicate raceme, or raceme inflorescence. Range Condition - The current productivity of rangelands relative to that land's natural productivity. Reduced - Smaller in size, frequently lacking parts; in flowers the sexual parts may be absent. Reduced floret - A floret that is either staminate or neuter. If it is highly reduced (e.g. awnlike structures) then it is sometimes called a rudimentary floret. Reflexed - Bent downward or backward from the apex. Resaca - An old river bed, e.g. and ox-bow. Resinous - Producing a viscous substance or resin. Reticulate - In the form of a network like some types of netted venation. Retrorse - Pointing downward toward the base, as do the barbs on Cenchrus

(sandbur). Revolute - Turned under along the margins toward the abaxial surface. Rhizome - A horizontal, underground stem with modified leaves at the nodes. Rhizomatous - Having rhizomes; horizontal underground stems with nodes and internodes. Rosette - A cluster of spreading or radiating basal leaves, as in Dichanthelium. Rounded - Having an arched apex rather than a pointed and angled apex. Rudiment - An imperfectly developed organ or part, specifically used in reference to florets. The rudiment of a spikelet is formed by structures of a reduced sterile floret. Rudimentary - Not fully developed and non-functional. Rugose - Wrinkled or folded; having horizontal folds in the surface. Saccate - Swollen or sac-shaped; see the second glume of Sacciolepis. Scabrous - Rough to the touch; caused by short, stiff, angled hairs on the surface. Scarious - Thin, dry, and membranous; not green (e.g., the margins of a Poa lemma). Schlerenchyma - A cell and tissue type in which the cells have both a primary cell wall and a secondary cell wall. Scutellum - Haustorial tissue of the embryo located between the endosperm and the plummule-radicle axis of the embryo. Second glume - The uppermost of the two glumes; an odd-veined, empty bract of the spikelet. Secondary - Not primary, subordinate; the branches that arise from the primary branches. Series - Number or group of similar objects arranged in a row. Serrate - Saw-toothed with the teeth angled toward the apex, sharp teeth. Sessile - Without a pedicel or stalk. Setaceous - Slender and bristle-like. Setae - A rigid bristle; sharp pointed bristle. Sheath - The lower part of a leaf that encloses the culm; typically open or split and overlapping at the margins. Short cell - Located in the epidermis of grasses, occurring in pairs of cork cells and silica cells. Silica cell - One of two types of short cells in the epidermis of grasses, silica cells have deposits of silica in them. Sinuate - Having a wavy margin. Solitary - Single; one. Spathe - A modified leaf sheath that subtends and often encloses some of the inflorescence.

Spatheate - Having a spathe. Species - The basic unit of classification. Spherical - Shaped like a globe or a ball. Spicate - Spike-like; resembling a spike inflorescence but having both sessile and pedicellate spikelets and flowers. Spicate raceme - Having both sessile and pedicellate spikelets on a rachis. Spike - An unbranched inflorescence in which the spikelets are sessile on the rachis (main axis). Spikelet - The basic unit of a grass inflorescence that typically consists of 2 glumes (except in some species where 1 or both glumes are lacking), 1 or more florets, and a rachilla. Spines - A sharp pointed, stiff body arising from the epidermis; in grasses these are usually flattened and modified inflorescence branches. Spiral - An arrangement of objects along the outline of a coiled spring. Spreading - Branches that are widely ascending to divergent from the main axis. Squarrose - Spreading rigidly at right angle; usually the shape of bracts. Stamen - The male organ of a flower, consisting of the pollen bearing anther on a slender filament. The collective term for stamen is androecium. Staminate - Containing stamen but not the pistil. Sterile - Without pistils. A sterile floret may be staminate or neuter. Not capable of producing a seed. Stigma - The part of the ovary or style that receives the pollen for fertilization. Stipe - A small stalk to a fascicle of spikelets; see the stalk of Pennisetum. S Stolon - A horizontal, above-ground stem with modified leaves, nodes, internodes, and axillary buds. Stoloniferous - Bearing horizontal above ground stems that root at the nodes. Striate - Marked with longitudinal grooves or lines; appearing striped. Sub - A prefix used to denote a lesser degree, an inferior rank, or a lower position. Subequal - Nearly equal in length. Subtend - To be below and close to; refers to position. Subterranean - Below ground or below the soil. Subulate - Awl-shaped. Succulent - Fleshy, soft or juicy. Systematics - The broad field concerned with the study of the diversity of plants and their identification, naming, classification, and evolution. Taxon - Term applied to any taxonomic group at any taxonomic rank. Terete - Cylindrical and slender, as the normal culm of a grass plant.

Terminal - Borne at or belonging to the extremity or summit; distal. Tessilate - A surface marked with square to rectangular depressions. Tiller - An erect, lateral shoot. Tomentose - Vestiture of dense, short, soft, matted hairs. Transverse - Crossing the width of an object. Triad - A group of three, as applied to spikelets of Chrysopogon or Hordeum. Consists of a sessile spikelet and two pedicellate spikelets. In Chrysopogon this represents a reduced racemose branch. Triangular - Three-sided. Truncate - The apex or base of a structure that is flat or ends abruptly. It appears to be cut off. Tuberculate - Bearing small projections or warty protuberances. Tufted - Caespitose; bunched. Turgid - Swollen; appearing to be filled from within. Undulate - Gently wavy. Unilateral - One sided or turned to one side (e.g., the spikelet arrangement on the branches of Bouteloua). Unisexual - Flowers that contain either stamens or pistils but not both. Vein - The vascular bundles or veins or ribs of the blades, glumes, lemmas, and paleas. Velvety - A vestiture of thick medium length hairs. Vernal - Growth form for spring and early summer. Verrucose - Covered with warty protuberances. Verticil - A whorl of parts arising from a common point or around an axis. Verticillate - In whorls or verticils. Vestigial - Not fully developed; rudimentary. Verification - The act of verifying. Vestiture - Surface coverings (e.g., hairs, or wax, or scales). Villous - Long, soft, unmated hairs; shaggy. Viscid - Sticky, glutinous. Voucher specimen - A herbarium specimen used as evidence or proof. Whorl(ed) - A cluster of 3-several branches around the inflorescence axis. Winged - Bearing a projection or border near the margins that resembles a wing. Xeric - A dry soil or habitat.