The Monocots: Part 2 Commelinoid Monocots Spring 2011

Phylogeny of Monocot Groups Acorales Alismatales Asparagales Liliales Dioscoreales Pandanales Arecales Poales Commelinales Zingiberales Basal “Petaloid” Commelinoid

Commelinoid characters Special type of epicuticular wax Starchy pollen UV-fluorescent compounds in the cell walls Starchy endosperm (except in the palms) Lots of molecular support

Commelinoid Monocot Groups Order Arecales - Palms Arecaceae (Palmae) Order Poales - Grasses - Bromeliads Cat-tails Rushes, Sedges, and Grasses Typhaceae Juncaceae Cyperaceae Poaceae (Gramineae) Order Zingiberales – Ginger, banana, and allies (no required families)

Commelinoid Monocots: Arecales: Arecaeae (Palmae) Widespread throughout tropical and warm temperate regions “Trees” or “shrubs”, typically unbranched Diversity: ca. 2,780 in 200 genera Flowers: usually sessile, in compound-spicate inflorescences, these subtended by a bract (spathe); ovule 1 per locule Significant features: Leaves alternate or spiral, blades plicate, splitting in a pinnate or palmate manner Special uses: coconut (Cocos nucifera), date (Phoenix dactylifera), rattan (Calamus), oils and waxes, ornamentals Required taxa: family only

Arecaceae Unbranched trunks Big leaves on top! Numerous small flowers Spathes + compound-spicate inflorescence 3 sepals + 3 petals Superior ovary (carpel fusion varies) Drupe

Arecaceae – The Palm Family

Arecaceae – Cocos nucifera

Arecaceae Economic plants and products: Phoenix dactylifera Dates

Characters of Poales Silica bodies (in silica cells) in the epidermis Styles strongly branched Loss of raphide (needle-like) crystals Much molecular support for monophyly Wind pollination has evolved several times independently within the order Ecologically very important

Commelinoid Monocots—Poales: Bromeliaceae (The Pineapple/Bromeliad Family) Tropical to temperate regions of the Americas Predominantly epiphytic herbs (“tank” plants) Diversity: ca. 1,520 species in 51 genera Flowers: radial, perianth differentiated into calyx and corolla, borne in axils of often brightly colored bracts; inflorescences spicate or paniculate; stigmas 3, usually twisted; seeds often winged or with tufts of hair Significant features: leaves with water absorbing peltate (or stellate) scales Special uses: pineapple (Ananas) Family not required; for information only

Bromeliaceae – Ananas comosus Fruit type?

Commelinoid Monocots—Poales: Typhaceae (The Cattail Family) Widely distributed, especially in Northern Hemisphere Aquatic & wetland rhizomatous herbs Diversity: 28 species in 2 genera Flowers: small, unisexual; separated spatially on dense, compact spicate or globose-clustered inflorescences; placentation apical Significant features: rhizomatous; long slender leaves; characteristic inflorescence Special uses: ornamental aquatics Required taxa: Typha

Typhaceae - Typha

Commelinoid Monocots—Poales: Juncaceae (The Rush Family) Worldwide, mostly temperate regions; wet or damp habitats Rhizomatous herbs, stems round and solid Diversity: 400 species in 6 genera Flowers: tepals 6, distinct; carpels 3 in superior ovary; stamens 6; fruit a loculicidal capsule Significant features: leaves 3-ranked, sheaths usually open Special uses: leaves used to weave rush baskets; some ornamentals Required taxa: Juncus

Juncaceae: Juncus -cymose inflorescences -leaf sheaths open -leaf blades flat, grooved, or cylindrical

Commelinoid Monocots—Poales: Cyperaceae (The Sedge Family) Worldwide, usually in damp or semi-aquatic sites Rhizomatous herbs, stems usually triangular in cross section Diversity: 4,500 species in 104 genera Flowers: with 1 subtending bract; tepals absent or reduced to 3-6 scales or hairs; stamens 1-3; carpels 2-3 in superior ovary; fruit an achene (nutlet) Significant features: Inflorescence a complex group of spikelets; leaf sheaths closed, ligule lacking; silica bodies conical Special uses: Papyrus used originally for paper; “water chestnuts”and a few other rhizomes edible, leaves used for weaving; some ornamentals. Required taxa: Carex, Cyperus

Cyperaceae versus Juncaceae: Field Character “Sedges have edges… …and rushes roll.”

Cyperaceae diversity

Cyperaceae spikelet flower + subtending bract = floret Flowers: Arranged in spikelets Reduced Wind-pollinated flowers Subtended by bract Reduced/absent perianth flower From Zomlefer 1994

Cyperaceae Cyperus Eleocharis Rhynchospora (note bristle perianth) Fruit type is the achene: very important in the taxonomy of the family.

Cyperaceae

Cyperaceae: Cyperus -leaves usually basal -ligules absent -spikelet scales distichous, each subtending a flower -spikelets flattened or cylindrical -flowers bisexual -no perigynium

Cyperaceae: Carex -presence of the perigynium (a sac-like bract surrounding the female flower) in addition to the subtending bract -leaves usually with a ligule

Commelinoid Monocots—Poales: Poaceae (Gramineae) (The Grass Family) Cosmopolitan Primarily herbs, often rhizomatous; “trees” in most bamboos; stems are called culms Diversity: 10,000 species in ca. 650 genera Flowers: small, perianth parts reduced to lodicules; each flower enclosed by two bracts (lemma and palea) = floret; stamens typically 3; carpels 3, but appearing as 2; fruit a caryopsis Significant features: 1-many florets aggregated into spikelets, each with usually 2 empty bracts (glumes) at the base; leaf with a ligule Special uses: many – grains, turf, fodder/forage, structural uses (e.g., bamboo). Required taxa: Zea, Triticum, Oryza

Economic importance Zea mays Oryza sativa Triticum aestivum weeds sugar cane bamboo

Ecological importance

Poaceae: vegetative structure ligule

Poaceae: spikelet and flower structure flower Images from Grasses of Iowa

The fruit wall (pericarp) is completely fused to the seed coat. Endosperm (3N; triploid) contains the bulk of starch storage in the seed. The embryo is a pre-formed grass plant, with apical meristems (for both shoot and root) and protective organs (coleoptile and coleorhiza) which emerge first during germination. Anatomy of the Caryopsis (Grain)

Origin of grasses ca mya in southern- hemisphere forests early grasses

Panicgrasses (Panicoideae) Rices (Ehrhartoideae) Bluegrasses (Pooideae) Bamboos (Bambusoideae) Puelioideae Pharoideae Anomochlooideae Needlegrasses (Aristidoideae) Lovegrasses (Chloridoideae) Micrairoideae Reeds (Arundinoideae) Oatgrasses (Danthonioideae) Major radiation in Oligocene- Miocene epochs into open habitats Origin of grasses ca mya in forests + Stamens reduced to 3

C 4 photosynthetic pathway (in warm season grasses) is advantageous under higher temperatures, higher light, and less water

Dispersal!

Poaceae (Gramineae) diversity

Oryza (rice) -aquatic or wetland herbs -one floret per spikelet -spikelets strongly flattened

Triticum (wheat) -annuals -dense inflorescences -spikelets sessile, one per node -2-9 florets per spikelet

Zea (maize or corn) -male and female spikelets usually on separate inflorescences -female inflorescences axillary, enclosed in 1 or more sheaths (husks), one sessile spikelet per node -male inflorescences terminal, with paired spikelets

For more information and images: The Grasses of Iowa

Grasses, Sedge, Rushes ! Stem terete, hollow, or solid, jointed Leaf ranks 2 Leaf sheath Open, ligule Inflor: Spikelets Perianth: Lodicules Fruit: Caryopsis Triangular, solid, not jointed 3 Closed Spikelets None or bristles/scales Achene Terete, solid, not jointed 3 Open Cymose 6 chaffy tepals Capsule

“Graminoids” - Comparison

Commelinales 5 families, 780 species, widespread in various habitats Not required

Commelinoid Monocots: Zingiberales Large herbs with vessels more or less limited to the roots Silica cells present in the bundle sheaths Leaves clearly differentiated into a petiole and blade Leaf blade with pinnate venation, often tearing between the second-order veins Leaf blade rolled into a tube in bud Petiole with enlarged air canals Flowers bilateral (or irregular) Pollen lacking an exine Ovary inferior Seeds arillate and with perisperm (diploid nutritive tissue derived from the nucellus) 8 families and nearly 2000 species Must be able to recognize the order!

Zingiberales diversity

Musaceae Musa