topic 03 overview of plant taxa

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Topic 03Overview of Plant Taxa

Lecture Reading:1 Plate 1 Reproductive Terminology (pp 978-979) in Rhoads & Block1. Plate 1. Reproductive Terminology (pp 978-979) in Rhoads & Block

(2007).2. Plate 2. Leaf Terminology (pp 980-981) in Rhoads & Block (2007).3. Rhoads & Block (2007) descriptions of all PA-native plant families

mentioned. 4. Angiosperm Phylogeny Group. 2009. An update of the Angiosperm

Phylogeny Group classification for the orders and families of flowering plants: APG III.

•Vascular•Rhizomatous / Stoloniferous•Free-sporing (lack seeds) with free-living gametophytes•Water needed for fertilization

I. Ferns & fern allies (pteridophytes)

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A. Club-mosses, lycophytes, or lycopods

Lycopodiaceae• Microphylls• Dichotomous branching• Sporangia (sing sporangium) in


Lycopodium

• Sporangia (sing. sporangium) in strobilus (pl. strobili) typical

I. Ferns & fern allies (pteridophytes)A. Club-mosses, lycophytes, or lycopods


Diphasiastrum


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I. Ferns & fern allies (pteridophytes)A. Club-mosses, lycophytes, or lycopods


Huperzia


B. Horsetails & Scouring-Rushes

Equisetaceae• Minute microphylls in whorls• Nodal, whorlar branching• Hollow ribbed stems


• Hollow, ribbed stems• Silicaceous stems• Sporangia in strobilus

Equisetum

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C. Leptosporangiate Ferns

Polypodiaceae sensu lato• Macrophylls (typically pinnate)• Circinate vernation• Branching variable

Equisetum


• Branching variable• Sporangia in sorus (pl. sori)• Leptosporangia

D. Whisk-Ferns

Psilotaceae• Rootless• Microphylls or enations• Branching dichotomous


Psilotum

• Branching dichotomous• Sporangia in synangium

Tmesipteris

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E. Phylogeny of Vascular plants

Club-mosses, lycophytes

1. Xylem & 2. Phloem; 3. Sporophyte dominant;4. Branched sporophytes

Rhyniophytes †

Ferns, horetails, & whisk-ferns

spermatophytes, seed plants1. Macrophylls (lost in modern horsetails and whisk-ferns)

1. Leaves; 2. Roots; 3. Clustered sporangia

p p y , p

1. Ovules/Seeds; 2. Pollen; 3. Eustele; 4. Vascular Cambium (wood)

Angiosperms

LycopodsSeed Plants

Angiosperms(vesseled seeds)

Gymnosperms(naked seeds)

Native Ferns & Horsetails

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II. Seed plants (spermatophytes)

• Eustele & vascular cambium (except in monocots)• Macrophylls• Branching axillary (except in cycads)• Spores retained gametophytes develop on parent sporophyte• Spores retained, gametophytes develop on parent sporophyte• Pollen (external water not required for fertilization) • Ovules and Seeds

II. Seed plants (spermatophytes)A. Gymnosperms

• Ovules exposed at pollination, seeds naked

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1. Cycads• Mostly unbranched, evergreen trees or shrubs with terminal rosette of

pinnate lvs.• Circinate vernation• Cataphylls• Cataphylls• Branching, when present, dichotomous or adventitious• Dioecious• Male sporangia in strobilus


1. CycadsCycadaceae (Cycas)

Zamiaceae (e.g., Zamia)

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2. GinkgosGinkgoaceae (Ginkgo)

• Branched, deciduous trees w/ fan-shaped lvs on short shoots

• Leaf venation dichotomous• Leaf venation dichotomous• Dioecious• Male sporangia in pendulous strobilus• Ovules on forked, pendulous peduncle


3. Conifers

• Trees or shrubs with needle-like or scale-like lvs• Mostly evergreen• Resin canals• Resin canals• Dioecious or monoecious• Male sporangia in strobilus• Ovules on branched strobilus called a “cone”

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3. Conifers

Female coneMale strobili


3. Conifers

Female coneMale strobili

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3. Conifers

Cupressaceae (Cypress family)•Lvs needle- or scale-like •Peltate, opposite cone scales•Seeds small, equilateral wing, >2 per scale

Pinaceae (pine family)•Lvs needle-like•Flat, spiraled cone scales•Seeds large, unilateral wing, 2 per scale


3. Conifers

Taxaceae (yew family)•Lvs needle-like•Small cone with 1-fertile scale w/ 1 seed

Taxus

•Fleshy aril from funiculus

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II. Seed plants (spermatophytes)B. Angiosperms or flowering plants

•Ovules concealed by female sporophylls (carpels) comprising pistil(s) at pollination •seeds in fruits•“Flowers”•Plants variable in habit

topic 03 overview of plant taxa

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