Wisconsin flora “wordle” - the grasses 321

279

• the second large independent shift to reduced and for wind pollination • 4th largest family - 620 genera, 10,000 • most important family (ethnobotanically) 283

1 2

grasses you collected! Picture key to grasses!

Setaria spp. – spp. – foxtail foxtail gerardii – scoparium– Andropogon gerardii – – big bluestem little bluestem big bluestem little bluestem Grasses of Iowa www.eeob.iastate.edu/research/iowagrasses

Field Guide to Wisconsin Grasses – book in lab nutans – Phalaris arundinacea – inermis– Indian grass reed canary grass smooth brome

3 4

1 III: wind pollinated families Poales III: wind pollinated families

• showy flowers, Evolutionary trends: • showy flowers, insect or bird insect or bird pollinated • nectar to gathering to pollinated wind pollination • +/- reduced • reduced flowers - loss of • +/- reduced flowers, insect or flowers, insect or wind pollinated wind pollinated • unisexuality sometimes • become important • reduced • reduced flowers, wind • flowers to florets in spikelets flowers, wind pollinated pollinated

5 6

Poaceae - grasses Poaceae - grasses Poaceae related to more typical, although reduced, flowered Poaceae related to more typical, although reduced, flowered graminoid monocots with 6 tepals – Southern Hemisphere! graminoid monocots with 6 tepals – Southern Hemisphere!

7 8

2 Poaceae - grasses Poaceae - grasses Poaceae related to more typical, although reduced, flowered graminoid monocots with 6 tepals – Southern Hemisphere! What has driven this large and successful adaptive • bracted radiation? • 6 tepals 5076 species • mixed male & female 4 species 12 species flowers 12 species • achene

female 5423 species male

9 10

Poaceae - grasses Poaceae - grasses

node Vegetative features • first diversified ca. 70 mya in late • jointed, hollow, Cretaceous – tropical circular stems understories (culms) • major radiations • 2-ranked or during formation of spiralled in mid Tertiary • blade, sheath, and ligule • shift to grasslands • intercalary basis for adaptive meristem above radiation? blade ligule nodes sheath Strömberg et al. PNAS 2005;102:11980-11984

11 12

3 Evolution of C4 Poaceae - grasses photosynthesis across angiosperms Adaptive features

• intercalary Poaceae meristem - & fire response

• silica in stems

• C4 photo- synthesis in arid “grasslands” • C4 photosynthesis evolved 62 times in angiosperms Nebraska 25 mya

13 14

Poaceae - grasses Poaceae - grasses

• has C4 photo- • has whole genome synthesis driven doubling been a key speciation? innovation for grass diversification? 5076 species 5076 species 4 species 4 species 12 species • C4 photosynthesis 12 species 12 species 12 species evolved 62 times in • WGD at base of angiosperms PACMAD and BOP clades 5423 species • 24 times just in 5423 species grasses • 11,000 vs. 28 spp.

• all in PACMAD clade

15 16

4 Poaceae - grasses Poaceae - grasses

The main unit of the Defining feature of is the grasses are the which is composed of 2 glumes (spikelet bracts) and 1 spikelet and its florets or more florets

Brome

spikelet glumes

florets glomerata Orchard grass

17 18

Poaceae - grasses Poaceae - grasses

Each floret is surrounded by This spikelet with two glumes two floret bracts - the outer has two florets each with two lemma and the inner palea floret bracts - the outer lemma (usually not seen until and the inner palea anthesis - when florets open)

Brome Oats

glumes

lemma lemma

palea palea Dactylis glomerata Orchard grass

19 20

5 Poaceae - grasses Poaceae - grasses

Although considerable variation occurs in florets (among species or within a spikelet), most of our species have the following floret anthesis – expose structure: anthers & styles fungal endophytes – preventing spores • Perianth represented by 2 lodicules entering fruit?

What is function of lodicules? What is function of lodicules?

21 22

Poaceae - grasses Poaceae - grasses

• fungal endophytes • fungal endophytes (ascomycetes) produce (ascomycetes) produce physiologically active physiologically active alkaloids alkaloids

• anti-herbivory defense against grazing mammals (defensive mutualism)?

Nebraska grassland 25 mya Nebraska grassland 25 mya

23 24

6 Poaceae - grasses Poaceae - grasses

Although considerable variation occurs in florets (among species or within a spikelet), most of our species have the following floret structure: bisexual floret

• phylogenetic analysis of turned out to be phylogeny of endophytic fungi! • Perianth represented by 2 lodicules • 3 • Superior gynoecium of 2 fused carpels Lynn Clark • One ovuled fruits called a grain or caryopsis = seed fused to wall What parts homologous to other flowers? Jonathan Wendel

25 26

Poaceae - grasses Poaceae - grasses

Although considerable variation occurs in florets (among species • lodicules = or within a spikelet), most of our • palea/lemma = sepals species have the following floret structure:

Toby Kellogg – Missouri Bot Gard

• Perianth represented by 2 lodicules • Stamens 3 • Superior gynoecium of 2 fused carpels • One ovuled fruits called a grain or caryopsis = seed fused to ovary wall What parts homologous to other flowers? What parts homologous to other flowers?

27 28

7 Poaceae - grasses Poaceae - grasses

South American origin!

BOP Grass

phylogenetics PACMAD

Basal grasses

29 30

Poaceae - grasses Poaceae - grasses

Anomochloa marantoidea Streptochaete

4 stamens!

Subfamily (no spikelets, lodicules)

31 32

8 Poaceae - grasses Poaceae - grasses

Subfamily (herbaceous bamboos)

Grass phylogenetics

Pharus Core grasses

33 34

Poaceae - grasses Poaceae - grasses

Bambusa

Subfamily Ehrhartoideae (stamens 6, but 2 styles)

Subfamily Bambusoideae Oryza sativa - rice (6 stamens, 3 lodicules, 3 stigmas) 2nd most important crop in the world Ochlandra

35 36

9 Poaceae - grasses Poaceae - grasses

Subfamily Ehrhartoideae annua - bluegrass (stamens 6, but 2 styles) Subfamily Ziziana aquatica - wild rice (Spikelets with more than one grain forming floret; Important native American food; Lemma with 5 nerves) unisexual spikelets Poa pratensis - bluegrass

37 38

Poaceae - grasses Poaceae - grasses

Dactylis glomerata - orchard grass

Elymus hystrix bottlebrush

Bromus inermis - bromegrass sativa - oats

39 40

10 Poaceae - grasses Poaceae - grasses Subfamily (large )

Phalaris arundinacea Reed canary grass

Calamagrostis canadensis - bluejoint grass Phragmites australis - common reed Circumboreal species; non- native populations have become invasive and displaced native populations

41 42

Poaceae - grasses Poaceae - grasses Subfamily (Spikelets arranged often one-sided)

Spartina pectinata cord grass

Cortaderia - plume grasses from curtipendula pampas Sideoats grass

43 44

11 Poaceae - grasses Poaceae - grasses Subfamily (2 florets, bottom reduced, sterile)

Digitaria - crabgrass

Panicum virgatum - switchgrass sp. - panic grass Setaria - foxtail

45 46

Poaceae - grasses Poaceae - grasses

Andropogon gerardii - big bluestem

Saccharum - - sorghum 47 48

12 Poaceae - grasses Poaceae - grasses

The origin of from teosinte wild relatives in involved few genes

Female spikelets condensed into Male spikelets in cob or spike panicle or tassel mays - maize - teosinte John Doebley Zea mays - maize 49 50

13