The Monocots Basal and “Petaloid” Groups

The Monocots Basal and “Petaloid” Groups Synapomorphies of Monocots • Root system adventitious • One cotyledon • Stems with scattered vascular bundles (no • • • • secondary growth); herbaceous Leaves parallel-veined with a sheathing base Flowers pentacyclic (5 whorls), trimerous Sieve cell plastids with several cuneate protein crystals Lots of molecular support for monophyly Additional features of monocots • Leaves formed from the basal end of the leaf primordium • Usually with monosulcate pollen • Lack glandular teeth on leaves Basal and “Petaloid” Monocot Groups Order Acorales Acoraceae Order Alismatales Araceae Alismataceae Order Liliales Liliaceae Order Asparagales Agavaceae Alliaceae Amaryllidacaee Iridaceae Orchidaceae Basal Monocots: Acorales: Acoraceae not required • Widespread, temperate throughout tropical regions • Aquatic herb • Diversity: 1-3 spp in genus (Acorus) • Flowers: typical of Araceae, coalesced into a spike-like spadix • Significant features: Sister to the rest of the monocots; contain ethereal oils • Special uses: none • Family not required, but Acorus evolutionarily important “Petaloid” Monocots—Alismatales: Araceae (The Arum Family) • • • • • • • Cosmopolitan; greatest diversity in tropical regions Terrestrial and aquatic herbs, vines, epiphytes, floating aquatics Diversity: 3,300 species, 109 genera Flowers: many, small; lacking extensive perianth, carpels 2-3; if unisexual then spatially separated in inflorescence or sometimes plants dioecious Significant features: inflorescence – spadix subtended by a spathe (specialized leaf) Special uses: many ornamentals; Colocasia as food Required taxa: Arisaema, Lemna • • • • -spathe margins overlapping below, spathe mostly arched above, striped or marked -spadix usually slender and elongate -flowers unisexual and only at the base of the spadix Araceae: Lemna and friends •Reduced plant body: no stem or leaves; sometimes no roots •Rarely flower “Petaloid” Monocots—Alismatales: Alismataceae : not required (The Water Plantain Family) • Widely distributed • Aquatic & wetland rhizomatous herbs • Number of species: 88 species, 15 genera • Flowers: sepals & petals distinct, many • • • apocarpous carpels; flowers or floral axes often whorled Significant features: rhizomatous Special uses: ornamental aquatics Family not required Liliales • Nectaries at base of tepals • Spots on tepals • Extrorse anthers “Petaloid” Monocots—Liliales: Liliaceae (The Lily Family) • Widely distributed in temperate regions of the Northern Hemisphere • Perennial herbs, usually with bulbs and contractile roots • Number of species: ca 600 species, in 16 genera • Flowers: tepals 6, distinct, carpels 3, stamens • Significant features: Fruit a loculicidal capsule, sometimes a berry; no onion-like odor • Special uses: many ornamentals • Required taxa: Erythronium, Tulipa “Petaloid” Monocots—Asparagales: Iridaceae • • • • • • • (The Iris Family) Widespread in tropical and subtropical regions; absent in Australia Perennial herbs forming rhizomes, corms, or bulbs Number of species: ca 1,750 species, 67 genera Flowers: radial or bilateral, showy; tepals 6, outer tepals often differentiated from inner; stamens (2) 3, opposite outer tepals; carpels 3, fused into an inferior ovary; fruit a loculicidal capsule Significant features: leaves unifacial or terete, equitant Special uses: many ornamentals; saffron ( Crocus sativus) Required taxa: Iris “Petaloid” Monocots—Asparagales: Orchidaceae • • • • • • • (The Orchid Family) Widespread throughout the world; maximal diversity in tropical regions Primarily epiphytes; some terrestrial herbs, occasionally vines Diversity: ca 20,000 species in 700-800 genera Flowers: showy, usually resupinate, bilateral, the median inner tepal differentiated into a labellum (lip); highly modified androecial and gynoecial parts, fused into a column; pollen grouped into soft or hard masses (pollinia) united by a stalk into a pollinarium; ovary inferior; placentation parietal; fruit a capsule dehiscing with (1-)3 or slits; seeds tiny, dust-like Significant features: among the most specialized of all angiosperm flowers Special uses: many ornamentals; Vanilla Required taxa: family only The Monocots Commelinid Monocots Commelinid 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 Commelinales – Spiderworts, bloodworts, pickerel weeds Order Zingiberales – Ginger, banana, and allies Order Poales – Bromeliads, Cat-tails, Rushes, Sedges, and Grasses Typhaceae Juncaceae Cyperaceae Poaceae (Gramineae) Commelinoid Monocots: Arecales: Arecaeae (Palmae) • • • • • • • Widespread throughout tropical and warm temperate regions “Trees” or “shrubs”, typically unbranched Diversity: ca 2,000 in 190 genera Flowers: usually sessile, in compound-spicate inflorescences, these subtended by a bract (spathe); ovule 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 Family not required Arecaceae •Numerous small flowers •Spathes + compound-spicate inflorescence •3 sepals + petals •Superior ovary (carpel fusion varies) •Drupe •Unbranched trunks •Big leaves on top! Commelinid 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 penni-parallel 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) families and nearly 2000 species Characters of Poales • Silica bodies (in silica cells) in the epidermis • Styles strongly branched • Loss of raphide (needle-like) crystals in most • Much molecular support for monophyly • Wind pollination has evolved several times independently within the order • Ecologically very important Commelinid Monocots—Poales: Bromeliaceae (The Pineapple/Bromeliad Family) • Tropical to temperate regions of the Americas • Predominantly epiphytic herbs (“tank” plants) • Diversity: ca 2,400 species in 59 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 Commelinid Monocots—Poales: Cyperaceae (The Sedge Family) • • • • • • • Worldwide, usually in damp or semi-aquatic sites Rhizomatous herbs, stems usually triangular in cross section and solid Diversity: 5,000 species in 104 genera Flowers: with 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 Flowers: •Arranged in spikelets •Reduced •Wind-pollinated flowers •Subtended by bract •Reduced/absent perianth flower + subtending bract = floret Fruit type is the achene: very important in the taxonomy of the family Commelinid Monocots—Poales: Poaceae (Gramineae) (The Grass Family) • • • • • • • Cosmopolitan Primarily herbs, often rhizomatous; “trees” in most bamboos; stems are called culms, hollow or solid Diversity: >10,000 species in ca 650 genera Flowers: small petals 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 empty bracts (glumes) at the base; leaf with a ligule Special uses: many – grains, turf, fodder/forage, structural uses (e.g., bamboo) Required taxa: family only Caryopsis (Grain) • 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 Grasses, Sedge, Rushes! •Triangular, solid, not obviously jointed •3 •Terete, solid, not obviously jointed •Leaf sheath Open, ligule •Closed •Open •Inflor: Spikelets •Spikelets •Cymose •Perianth: Lodicules •None or bristles/scales Achene •6 chaffy tepals •Stem terete, hollow, or solid, jointed •Leaf ranks •Fruit: Caryopsis •3 •Capsule ... Additional features of monocots • Leaves formed from the basal end of the leaf primordium • Usually with monosulcate pollen • Lack glandular teeth on leaves Basal and “Petaloid” Monocot Groups Order Acorales... Sister to the rest of the monocots; contain ethereal oils • Special uses: none • Family not required, but Acorus evolutionarily important “Petaloid” Monocots Alismatales: Araceae (The Arum Family)... slender and elongate -flowers unisexual and only at the base of the spadix Araceae: Lemna and friends •Reduced plant body: no stem or leaves; sometimes no roots •Rarely flower “Petaloid” Monocots Alismatales: