CENTRAL FLORIDA GRAMINOID IDENTIFICATION WORKSHOP

Introduction to Florida’s Graminoids

Erick A. Revuelta St. Johns River Water Management District October 2019 GRAMINOIDS

Graminoids: grass and grass-like plants. Specifically: grasses (GRAMINEAE/POACEAE), sedges (CYPERACEAE) and rushes (JUNCACEAE).

Adapted to a wide range of conditions:

• Anaerobic soil conditions (wetlands) • Xeric conditions • Saline environments (saltmarshes) • Fire

Erick Revuelta 2019 FLORIDAFLORIDA GRAMINOIDSGRAMINOIDS

Graminoids account for nearly 16% of species in Florida

POACEAE – 446 species CYPERACEAE – 276 species JUNCACEAE – 24 species

Graminoid-dominated communities represent

• 30% of Florida’s natural communities • 18% of Florida’s land mass

Erick Revuelta 2019 FLORIDA GRAMINOIDS

Notable species:

Aristida stricta (POACEAE)

• Wet flatwoods • Mesic flatwoods • Scrubby flatwoods • Sandhill • Upland pine

Spartina alterniflora (POACEAE)

• Saltmarsh

Cladium jamaicense (CYPERACEAE)

• Everglades marsh • Freshwater marsh • Floodplain marsh

Juncus roemerianus (JUNCACEAE)

• Juncus marsh

Erick Revuelta 2019 AA grass,grass, asedge sedge or or rush? a rush?

Sedges have edges, rushes are round, grasses have joints all the way to the ground

USUALLY!

Some sedges don’t have obvious edges Rushes are always round but so are many grasses and sedges Grass nodes or joints are not always easy to find

Diminutive parts and superficial similarities make graminoid identification difficult…

Does it really matter? A grass, a sedge or a rush?

Take time and work through each of these questions. You will find that some may not have a clear cut answer:

• Are the leaves 2- or 3-ranked?

• Are the stems trigonous (three-sided) or round?

• Does the stem have swollen nodes (joints)?

• Are the stems hollow, pithy or solid?

• Is the inflorescence subtended by bracts (modified leaves)?

• Is the fruit a capsule with many seeds, seeds individually contained by a pair of scales, or an individual seed contained by a single scale?

Erick Revuelta 2019 ComparingA grass, Grasses, sedge Sedgesor rush? and Rushes

Character Cyperaceae Juncaceae Poaceae

Habitat Throughout Mostly wet habitats Throughout

Triangular in cross section Terete (round) Terete to ellipsoid

Stems Internodes solid Internodes solid Internodes mostly hollow

Nodes not jointed Nodes not jointed Nodes jointed

3-ranked 3-ranked 2-ranked

Flat or channeled and Leaves Round, reduced, or flat. Flat, channeled or round sometimes reduced or lacking

Sheath open Sheath open Sheath closed

Subtended by bracts Subtended by bracts Inflorescence Not subtended by bracts (usually prominent) (reduced, not prominent)

Achene contained by Caryopsis (grain) contained by Fruit A capsule with many seeds a single scale 2 scales (palea and lemma) POACEAEComparative – THE Morphology GRASS FAMILY- Stems

ROUND STEMS TRIGONOUS STEM

Credit: Hilton Pond Center Credit: Hilton Pond Center Credit: Hilton Pond Center

SOLID STEMS

HOLLOW STEMS

Erick Revuelta 2019 ComparativePOACEAE Morphology – THE GRASS – Leaf FAMILY Arrangement

Distichous (2-ranked) leaf arrangement, leaves emerge on opposite Whorled (3-ranked) arrangement, leaves spirally ascending along the sides of the stem. Not to be confused with an opposite leaf stem. Unfortunately this is not always obvious. arrangement in non-graminoid species.

Erick Revuelta 2019 POACEAEComparative – THE Morphology GRASS -FAMILYLeaves

GRASSES RUSHES SEDGES

Leaves flat, channeled or round Often reduced Sometimes reduced to just the sheath Parallel venation Round (2 species with flat leaves), septate Leaves channeled (V or W shaped) Midvein often prominent Midvein and venation not prominent Midvein, venation not prominent Hairs present in many species Glabrous Glabrous

Erick Revuelta 2019 ComparativePOACEAE Morphology– THE GRASS - Inflorescence FAMILY

Inflorescence arrangement variable. Inflorescence arrangement variable. Inflorescence arrangement The seed (caryopsis) contained by two Subtended by bracts, often equal or variable. Subtended by modified bracts (palea and lemma). larger in size than the blades. The seed reduced bracts. The seeds (achene) contained by a single scale. (many) contained in three- sided capsule.

Erick Revuelta 2019 POACEAEGrass Inflorescence – THE GRASS - Diversity FAMILY

Panicle Raceme Spike

Erick Revuelta 2019 POACEAESedge Inflorescence – THE GRASS - Diversity FAMILY

Erick Revuelta 2019 POACEAERush Inflorescence – THE GRASS - Diversity FAMILY

Erick Revuelta 2019 ComparativePOACEAE Morphology – THE GRASS – Inflorescence FAMILY Unit

Spikelet Spikelet Capsule (many florets) (many florets 1 seed per bract)

Erick Revuelta 2019 POACEAEPOACEAE – THE– T HEGRASSGRASSES FAMILY

Poaceae/Gramineae: 1 3 5

446 species, 120 genera • Important/large genera include: Aristida (22), Andropogon (18), Node/Joint Dichanthelium (24), Digitaria Credit: Hilton Pond Center (20), Eragrostris (29), Panicum (16), Paspalum (30), Setaria 2 4

(15), Urochloa (14) Blade • Wide range of habitats Internode

Morphological Features: • Stems have swollen joints/nodes (5) • Internodes hollow or pithy (1, 5) • Leaves 2-ranked, with parallel venation (3, 5) • Many species will have Sheath prominent midvein (3) • Sheaths open (4, 5)

Erick Revuelta 2019 SpikePOACEAE and Spikelet – THE Diversity GRASS FAMILY - Grasses

Credit: Old Dominion University Credit: Keith Bradley

Credit: Harry Rose

Credit: Alexey Sergeev

Erick Revuelta 2019 CYPERACEAE – THE SEDGES

Cyperaceae: 276 species, 21 genera

• 80% of all the species belong to four genera: Carex (73), Cyperus (58), Rhynchospora (56), Eleocharis (30) • Freshwater or brackish wetland habitats

Morphological Features:

• Annual or perennial, rhizomatous or cespitose • Stems/culms trigonous sometimes almost round, pithy • Leaves present or absent, flat, V or W-shaped • Inflorescence various (panicles, glomerules, heads), usually subtended by bracts • Fruit an achene, lenticular or trigonous; with or without bristles Credit: Hilton Pond Center

Erick Revuelta 2019 SpikePOACEAE and Spikelet – THE DiversityGRASS FAMILY - Sedges

CYPERACEAE

Erick Revuelta 2019 JUNCACEAEJUNCACEAE - THE– T RUSHHE RUSHES FAMILY

Juncaceae: 24 species, in 2 genera

• Juncus (22) and Luzula (2) • Freshwater wetlands (except J. roemerianus)

Morphological Features:

• Cespitose or rhizomatous • Leaves 3-ranked, mostly terete (round) Credit: floridagrasses.org Credit: John R. Gwaltney and septate, a few species have flat leaves • Culm (stems) pithy or solid • Nodes without joints • Inflorescence an open or congested panicles, heads • Sheaths fused or overlapping • Fruit is a capsule containing many seeds Credit: Hilton Pond Center Credit: floridagrasses.org

Erick Revuelta 2019 CapsulePOACEAE and Inflorescence – THE GRASS Diversity FAMILY - Rushes

Capsule Inflorescence

Inflorescence Inflorescence terminal appearing lateral Flowers/capsules Flowers/capsules Capsules in tight borne singly borne in clusters head-like clusters 2+

J. effusus J. dichotomous J. marginatus J. megacephalus J. roemerianus J. repens J. paludosus J. elliottii J. polycephalus J. scirpoides

Erick Revuelta 2019 A grass,grass, sedge sedge or or rush? rush?

Credit: D. Walters and C. Southwick Credit: Caty Chayka

Erick Revuelta 2019 A grass, sedge or rush?

Erick Revuelta 2019 A grass, sedge or rush?

Credit: Caty Chayka

Erick Revuelta 2019 Collecting Specimens

Collecting specimens:

• Pictures are good but specimens are better

• Mature inflorescence whenever possible

• Complete specimen (including the roots)

• Keep specimens fresh

• Make a mental note of the habitat where the plant was growing

Erick Revuelta 2019 Resources

Online Resources:

• USF ISB Plant Atlas (http://florida.plantatlas.usf.edu/)

• Flora of North America Online (http://beta.floranorthamerica.org/Main_Page)

• Florida Grasses (http://www.floridagrasses.org/)

• Open Herbarium (https://openherbarium.org/)

• The Institute for Regional Conservation (https://www.regionalconservation.org/)

• Southeastern Flora (http://www.southeasternflora.com/index.php)

Erick Revuelta 2019 Resources

Books & Guides:

Harrington. How to Identify Grasses and Grasslike Plants

David Hall. Grasses of Florida

Hitchcock. Manual of the Grasses of the United States

McMillan. Rhynchospora (Cyperaceae) of South Carolina and Eastern United States

Wunderlin and Hansen. Guide to the Vascular Plants of Florida

Godfrey and Wooten. Aquatic and Wetland Plans of Southeastern United States

FDEP. Florida Wetland Plants: An Identification Manual

Erick Revuelta 2019