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Topic 03 Overview of Plant Taxa Lecture Reading: 1. 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. Angi osperm Phy logeny Group. 2009. An up da te o f the Ang iosperm Phylogeny Group classification for the orders and families of flowering plants: APG III.
I. Ferns & fern allies (pteridophytes)
•Vascular •Rhizomatous / Stoloniferous •Water needed for fertilization •Free-sporing (lack seeds)
I. Ferns & fern allies (pteridophytes) A. Club-mosses, Lycophytes, or lycopods
Lycopodiaceae • Microphylls • Dichotomous branching • Sporangia in strobilus typical
Lycopodium
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I. Ferns & fern allies (pteridophytes) A. Club-mosses, Lycophytes, or lycopods
Lycopodiaceae • Microphylls • Dichotomous branching • Sporangia in strobilus typical
Diphasiastrum
I. Ferns & fern allies (pteridophytes) A. Club-mosses, Lycophytes, or lycopods
Lycopodiaceae • Microphylls • Dichotomous branching • Sporangia in strobilus typical
Huperzia
I. Ferns & fern allies (pteridophytes) B. Horsetails & Scouring-Rushes
Equisetaceae • Minute microphylls in whorls • Nodal, whorlar branching • Hollow, ribbed stems • Silicaceous stems • Sporangia in strobilus Equisetum
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I. Ferns & fern allies (pteridophytes) C. Leptosporangiate Ferns Equisetum Polypodiaceae sensu lato • Macrophylls (typically pinnate) • Circinate vernation • Branching variable • Sporangia in sorus (plural sori) • Leptosporangia
I. Ferns & fern allies (pteridophytes) D. Whisk-Ferns
Psilotaceae • Rootless • Microphylls or enations • Branching dichotomous • Sporangia in synangium (plural synangia)
Psilotum
Tmesipteris
E. Phylogeny of Vascular plants
Xylem & Phloem; rhyniophytes † Sporophyte dominant; Dichotomous branching of sporophytes Club-mosses, lycophytes
Ferns, horetails, & whisk-ferns Leaves (Microphylls); Roots; Clustered sporangia Macrophylls spermatophytes, seed plants
Seeds; Pollen; Eustele; Vascular Cambium (wood)
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E. Phylogeny of Vascular plants
Hollow internodes; Ribbed stem; Interaxillary branching with whorled phyllotaxy horsetails, scouring-rushes
whisk-ferns LfllftLoss of lvs; loss of roots; synangia Stelar characters Leptosporangiate ferns
Leptosporangia
II. Seed plants (spermatophytes)
• Eustele & vascular cambium (except in monocots) • Macrophylls • Branching axillary (excep in cycads) • 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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II. Seed plants (spermatophytes) A. Gymnosperms 1. Cycads • Mostly unbranched, evergreen trees or shrubs with terminal rosette of pinnate lvs. • Circinate vernation • Cataphylls • Branching, when present, dichotomous or adventitious • Dioecious • Male sporangia in strobilus
II. Seed plants (spermatophytes) A. Gymnosperms Zamiaceae (e.g., Zamia) 1. Cycads Cycadaceae (Cycas)
II. Seed plants (spermatophytes) A. Gymnosperms 2. Ginkgos Ginkgoaceae (Ginkgo) • Branched, deciduous trees w/ fan-shaped lvs on short shoots • Leaf venation dichotomous • Dioecious • Male sporangia in pendulous strobilus • Ovules on forked, pendulous pedlduncle
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II. Seed plants (spermatophytes) A. Gymnosperms 3. Conifers
• Trees or shrubs with needle-like or scale-like lvs • Mostly evergreen • Resin canals • Dioecious or monoecious • Male sporangia in strobilus • Ovules on branched strobilus called a “cone”
II. Seed plants (spermatophytes) A. Gymnosperms 3. Conifers Male strobili Female cone
II. Seed plants (spermatophytes) A. Gymnosperms 3. Conifers Male strobili Female cone
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II. Seed plants (spermatophytes) A. Gymnosperms 3. Conifers
Pinaceae (pine family) Cupressaceae (Cypress family) •Lvs needle-like •Lvs needle- or scale-like •Flat, spiraled cone scales •Peltate, opposite cone scales •Seeds large, unilateral wing, 2 per scale •Seeds small, equilateral wing, >2 per scale
II. Seed plants (spermatophytes) A. Gymnosperms 3. Conifers
Taxaceae (yew family) •Lvs needle-like •Small cone with 1-fertile scale w/ 1 seed •Fleshy aril from funiculus
Taxus
II. Seed plants (spermatophytes) B. Angiosperms or flowering plants •Ovules concealed by carpels comprising pistil(s) at pollination seeds in fruits •“Flowers” •Plants variable in habit
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