Diversity and Evolution of Asterids
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Asterids • continue survey through the eudicots or Diversity and Evolution tricolpates after completing Rosids • the Asterids are the second of the two of Asterids large groups of dicots and the easier one to define morphologically . dogwoods, blueberries, and primroses . rosid asterid Asterid Characteristics Asterid Characteristics • fused petals - sympetaly • iridoid compounds (with losses) • ‘basal asterids’ have them (previously not placed • stamen number < petal number with asterids) • stamens fused to corolla tube Rubiaceae Plantaginaceae coffee family snapdragon family Gardenia Picrorhiza kurroa 1 Asterid Characteristics Asterid Composition • one layer of integuments in ovule vs. two in other groups • composition of Asterids is largely congruent with previous morphology • the “unitegminae” (vs. bitegminae) of van Tieghem in 1901 = new Asterid group! bitegminae Asterid Composition Asterid Composition • exceptions include the ‘basal asterids’ • exceptions include the ‘basal asterids’ and separate petal or small flower orders and separate petal or small flower orders • some of these “non” sympetalous Asterids (e.g., order Cornales) have “early” petal ring primordia in Apiaceae - carrot family development • subsequent petal development is separate, so appear to be polypetalous! Aquifoliaceae - holly family Early ring primordia of 5 petals in snapdragon (a true asterid) [EMBO Journal (2003) 22: 1058–1066] 2 Basal Asterids Cornales • basal asterids represent a grade towards • order sister to remainder of Asterids, the core asterids comprises 7 small families (diverse) • great variation in floral form in the two orders Cornales and Ericales • the “standard” Asterid flower has not been fixed Hydrangeaceae Nyssaceae Cornus Chimaphila Cornaceae Loasaceae *Cornaceae - dogwoods *Cornaceae - dogwoods • mainly north temperate shrub family of 2 genera and 85 species • opposite, simple leaves • arcuate venation Alangium Cornus 3 *Cornaceae - dogwoods ‘Pseudanthia’ in the Asterids – remember this ! Cornus stolonifera - red osier CA 4 CO 4 A 4 G (2)__ bracts Cornaceae Apiaceae Rubiaceae • 4 merous, small flowers with separate petals • 2 carpellate inferior ovary • fruit a 2-seeded ‘drupe’ • some inflorescences surrounded by showy bracts • “head” or “pseudanthium” (false Asteraceae Caprifoliaceae Adoxaceae flower) *Cornaceae - dogwoods *Cornaceae - dogwoods Cornus canadensis - bunch berry Low to ground boreal Eastern North American subshrub, appears to have a small tree with 4 whorl of leaves, and has 4 conspicuous white bracts showy bracts below flowers Cornus florida - flowering dogwood 4 *Cornaceae - dogwoods Hydrangeaceae - hydrangeas Another small family of trees, shrubs, and vines from North Temperate region - many ornamental woody plants • most recently placed in Saxifragaceae Cornus foemina Hydrangea arborescens Gray dogwood Common component of shrub carr Philadelphus - Cornus sericea Common in wet places, Hydrangea mock orange Red-osier distinctive with red stems Ericales Ericales • Ericales represent less than 6% of eudicot diversity, and 1/3 • large, important order of 23 families, >11,000 species of these belong to Ericaceae alone . but • will focus on just a few families and learn • 10% of the understory species in tropical rainforests *Ericaceae (blueberries) and *Primulaceae • and about 22% of the total stems in these forests (primroses) Clavija blueberry primrose 5 Ericales Ericales • Ericales exhibit great diversity in habit and nutrient uptake • Ericales exhibit great diversity in habit and nutrient uptake strategies strategies • mycorrhizal associations • parasitism • mycorrhizal parasites (mycotrophs) • carnivory Monotropa - Mitrastema - Indian pipe Arctostaphylos - bearberry parasite Sarracenia - pitcher plant Ericales Corolla Structure • as early diverging Asterids, Ericales sympetaly polypetaly exhibit a bewildering mixture of Rosid and Asterid features Fouquieria Couroupita for instance in … Rosid core Asterid Fouquieriaceae Lecythidaceae Primulaceae Roridulaceae 6 Corolla Structure Integument Number unitegmic bitegmic Re-examined in light of DNA based relationships Schoenenberger, Anderson, Sytsma 2005 • corolla evolution is still complicated • perhaps one or two separate origins of sympetaly and two or three reversals to choripetaly Clethra Jacquinia for instance in … Clethraceae Theophrastaceae Symplocaceae Marcgraviaceae Integument Number Stamen Number 1 whorl 2+ whorls Re-examined in light of DNA based relationships Schoenenberger, Anderson, Sytsma 2005 • ovule integument evolution is still complicated • multiple switches from the derived asterid condition of unitegmic to bitegmic and back again Shortia Schima for instance in … Polemoniaceae Theaceae Roridulaceae Actinidiaceae 7 Theaceae - tea, camellia Theaceae - tea, camellia North Temperate family of evergreen, serrate leaved shrubs (7 genera and up to 400 species) Stewartia malacodendron Camellia sinensis - tea Eastern North America and Eastern Asia is the “classic” north Schima temperate disjunction • flowers have separate petals pattern and many stamens Stewartia sinensis Stewartia pseudocamellia *Ericaceae - blueberries *Ericaceae - blueberries Worldwide woody family, except • comprises the former families lowland tropics, of 126 genera Pyrolaceae, Monotropaceae, and nearly 4,000 species Empetraceae, Epacridaceae • the E. Asian genus Enkianthus is sister to the rest of the family Moneses Epacris Monotropa Empetrum Enkianthus 8 *Ericaceae - blueberries *Ericaceae - blueberries • characteristic of nutrient poor soils - bogs, acidic pine dominated • mycotrophs - lacking chlorophyll and totally parasitizing the forests, tropical epiphytes, or sandy soils fungus for food, nutrients, and water • former family Monotropaceae, derived from within mycorrhizal • mycorrhizal relationship, forming haustoria - root to fungus Ericaceae connection, permits nutrient uptake by plants, carbon uptake by fungus Leatherleaf in bog Cavendisia - cloud forest epiphyte Monotropa uniflora Hypopitys monotropa Pterospora andromedea Indian-pipe Pinesap Giant pinedrops *Ericaceae - blueberries *Ericaceae - blueberries __ • evergreen, tough, leathery leaves CA (4-5) CO (4-5) A 8,10 G (4-5) • often revolute or inrolled • sunken stomata, and bottom of leaves • calyx and corolla are fused, the corolla often covered with protective hairs tube bell or vase shaped • stamens are 2X the number of petals; • often exhibit terminal pores for pollen release for buzz pollination by bees Arctostaphylos Rhododendron (Ledum) bearberry Labrador tea Chimaphila Note revolute leaves shinleaf 9 *Ericaceae - blueberries *Ericaceae - blueberries __ CA (4-5) CO (4-5) A 8,10 G (4-5) Andromeda glaucophylla - bog rosemary • pistil is superior, but inferior in blueberries and relatives • fruit a berry or capsule with 4-5 partitions and Rhododendron groenlandicum Kalmia polifolia - many seeds Labrador tea pale laurel Chamaedaphne calyculata leatherleaf Superior pistil Inferior pistil Bog species *Ericaceae - blueberries *Ericaceae - blueberries Creeping subshrub often seen on beaches “uva-ursi” translates as bearberry, indicating at least one dispersal agent of the plant Vaccinium myrtilloides V. macrocarpon Velvet-leaf blueberry cranberry Arctostaphylos uva-ursi Blueberries and cranberries are Bearberry inferior ovaried and berry fruited Vaccinium angustifolium Lowbush blueberry 10 *Ericaceae - blueberries *Ericaceae - blueberries Major family of the harsh Mediterranean climate regions of Chancellor Blank and the world Dean VandenBosch at Cranberry Creek Arbutus menziesii – CA madrone Arbutus in Europe V. macrocarpon cranberry *Ericaceae - blueberries *Primulaceae - primroses rhododendrons and Chiefly north temperate family of scapose herbs (or azaleas are prized opposite leaved) - 9 genera and about 900 species ornamentals - greatest species diversity in Himalayas Wisconsin Dells Primula (Dodecatheon) - Primula - shooting star primrose Rhododendron lapponicum - lapland rosebay 11 *Primulaceae - primroses *Primulaceae - primroses CA (5) CO (5) A 5 G (5) CA (5) CO (5) A 5 G (5) • 5 merous, stamens attached unto • pistil is unilocular and free-central petals, and opposite the petals rather • fruits are capsules than the sepals Primula - shooting star Lysimachia - loosestrife Dodecatheon - shooting star *Primulaceae - primroses *Primulaceae - primroses 1. On the various contrivances by which British and foreign orchids are fertilised by insects, and on the good effects of intercrossing. (1862) 2. Variation of plants and animals under domestication. (1868) 3. Movement and habits of thrum pin climbing plants. (1875) Primula - the classic study organism for 4. Insectivorous plants. (1875) 5. The effects of cross and self dimorphic heterostyly - Darwin fertilization in the vegetable kingdom. (1876) 6. The different forms of flowers on plants of the same species. (1877) 7. The power of movement in plants. (1880) Pollen and stigmatic differences in thrum and pin flowers 12 *Primulaceae - primroses *Primulaceae - primroses Primula meadii shooting star Lysimachia ciliata Fringed loosestrife Basal leaves (formerly in Dodecatheon) Opposite leaves P. fassettii Lysimachia thyrsiflora Western shooting star Swamp candles *Primulaceae - primroses Sarraceniaceae - pitcher plants Insectivorous family of 3 genera - New World; related to South African • flower is unusual with carnivore Roridulaceae 7 merous perianth Darlingtonia - • note how stamens are cobra lily lined up with petals rather than sepals • one of the most ubiquitous