9/28/2012 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. Ang iosperm 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 1 9/28/2012 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 2 9/28/2012 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) 3 9/28/2012 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 4 9/28/2012 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 5 9/28/2012 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 6 9/28/2012 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 7.