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The Monocots: Part 2 Commelinid Monocots Spring 2012.

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Presentation on theme: "The Monocots: Part 2 Commelinid Monocots Spring 2012."— Presentation transcript:

1 The Monocots: Part 2 Commelinid Monocots Spring 2012

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

3 Fig. 7.17

4 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

5 Fig. 7.45

6 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)

7 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 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 Family not required

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

9 Arecaceae – Cocos nucifera

10 Arecaceae Economic plants and products: Cocos nucifera Coconut, oil

11 Arecaceae Economic plants and products: Phoenix dactylifera Dates

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

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

14 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) 8 families and nearly 2000 species

15 Fig. 7.55

16 Zingiberales diversity

17 Fig. 7.56

18 Musaceae Musa

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

20 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

21 Fig. 7.63

22 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

23 Bromeliaceae: Tillandsia (Spanish moss)

24 Bromeliaceae – Ananas comosus Fruit type?

25 Commelinoid Monocots—Poales: Typhaceae (The Cattail Family) Widely distributed, especially in Northern Hemisphere Emergent aquatic rhizomatous herbs Diversity: 8-13 species in 1 genus Flowers: small, unisexual; separated spatially on dense, compact spicate inflorescences; placentation apical Significant features: rhizomatous; long slender leaves; characteristic inflorescence Special uses: ornamental aquatics Required taxa: Typha

26 Sparganium This genus is placed in its own family, the Sparganiaceae, in your text, but it is closely related to Typhaceae and is included in Typhaceae in many treatments. Typha

27 Commelinid Monocots—Poales: Juncaceae (The Rush Family) Worldwide, mostly temperate regions; wet or damp habitats Rhizomatous herbs, stems round and solid Diversity: 350 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

28 Juncaceae Juncus Distichia

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

30 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 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

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

32 Fig. 7.65 Fig. 7.66D

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

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

35 Cyperaceae

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

37 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 -ecologically important, especially in wetlands

38 Cyperaceae: Carex

39 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 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: family only

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

41 Ecological importance

42 Poaceae: vegetative structure ligule

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

44 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)

45 Poaceae: caryopsis (grain) Setaria foxtail Zea mays corn or maize

46 Origin of grasses ca. 70-80 mya in southern- hemisphere forests early grasses

47 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. 70-80 mya in forests + Stamens reduced to 3

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

49 Dispersal!

50 Poaceae: Bambusoideae

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

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

53 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

54 For more information and images: The Grasses of Iowa

55 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 obviously jointed 3 Closed Spikelets None or bristles/scales Achene Terete, solid, not obviously jointed 3 Open Cymose 6 chaffy tepals Capsule

56 “Graminoids” - Comparison

57 Next time: The “Basal” Eudicots…

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