BIOL 317: Plant Identification and Classification Summer 2015 - Notes Week 6 – Tuesday Plant reproduction and breeding systems(cont.) Advantages of different breeding systems • asexual reproduction and selfing . reproductive assurance - can reproduce even in small, isolated populations . reduced reproductive effort - no need to produce showy flowers or flowers at all . locally adapted offspring in stable environments . 100% of genes passed to offspring • outcrossing . greater genetic variability in offspring - especially useful in changing environments . reduces inbreeding depression - maintenance of heterozygosity hides expression of deleterious recessive alleles Myrtales other important families include Lythraceae (loosestrife, crape myrtle, pomegranate) and Myrtaceae (eucalyptus, guava, allspice) Onagraceae (evening-primrose family) 22 genera, 656 spp. distributed widely, but especially diverse in western North America and South America herbaceous or woody (shrubs) leaves - simple; variously arranged flowers • actinomorphic or zygomorphic • hypanthium common • sepals usually 4 • petals usually 4 • stamens 4 or 8 . pollen held in strands by sticky viscin threads • pistil compound (4 carpels); ovary inferior • fruit: capsule or berry includes PNW wildflowers (Chamerion angustifolium - fireweed, Oenothera spp. - evening-primrose, Epilobium spp. - willowherb, Clarkia spp., etc.) and ornamentals (Fuchsia spp. - fuchsia, Oenothera spp., Epilobium spp., etc.) Brassicales other important families include Capparidaceae (caper; sometimes included in expanded Brassicaceae) and Caricaceae (papaya) Brassicaceae/Cruciferae (mustard family) 338 genera, 3710 spp. distributed widely, but especially diverse in northern temperate zone herbaceous leaves - simple or compound; alternate or basal flowers • usually actinomorphic • sepals 4 • petals 4, often forming cross shape • stamens 6 . tetradynamous - 4 long inner stamens and 2 short outer stamens • pistil compound (2 carpels); ovary superior • fruit: silique (long and skinny, >2 times longer than wide) or silicle (round, <2 times longer than wide) . persistent replum - "false" septum with thickened placenta around margin glucosinolates - sulfur-containing chemical compounds are transformed by the enzyme myrosinase into isothiocyanates (mustard oils) for herbivore defense includes PNW wildflowers (Erysimum spp. - wallflower, Phoenicaulis cheiranthoides - daggerpod, Arabis spp. - rockcress, etc.), weeds (Alliaria petiolata - garlic mustard, Capsella bursa-pastoris - shepherd's purse, Cardamine hirsuta - bittercress, etc.), food crops (Brassica oleracea - cabbage, kale, Brussels sprouts, broccoli, cauliflower, kohlrabi; Brassica rapa - turnip, Chinese cabbage; Brassica nigra - mustard, Brassica napus - canola, Raphanus sativus - radish, Eruca sativa - arugula, Armoracia rusticana - horseradish, Eutrema japonicum - wasabi, etc.), model system in biological research (Arabidopsis thaliana), and ornamentals (Erysimum spp., Lunaria annua - honesty, Lobularia maritima - sweet alyssum, etc.) Sapindales other important families include Anacardiaceae (sumac, poison ivy, mango, cashew) and Rutaceae (citrus) Aceraceae (maple family) 2 genera, 113 spp. distributed in northern temperate zone woody (trees or shrubs) leaves - simple or compound; opposite; often palmately lobed flowers • some unisexual, especially in wind-pollinated species; plants monoecious, dioecious, or androdioecious (some plants with perfect flowers, some plants with staminate flowers) • actinomorphic • sepals 4-5 • petals 4-5; some reduced, especially in wind-pollinated species • stamens 4-10 . some form nectary disk at base of stamens • pistil compound (2 carpels); ovary superior • fruit: samaroid schizocarp (splits into one-carpel sections; each section is winged) species in Sapindaceae sensu stricto, which includes mostly tropical members with more diverse floral morphologies, formed a paraphyletic group when Aceraceae was excluded, so more recent classifications have expanded Sapindaceae to include Aceraceae includes PNW trees and shrubs (Acer macrophyllum - big-leaf maple, Acer circinatum - vine maple, Acer glabrum - Douglas maple), food crop (Acer saccharum - sugar maple [source of maple syrup]), and ornamentals (Acer palmatum - Japanese maple, etc.) Malvales Malvaceae former families Bombacaceae, Sterculiaceae, and Tiliaceae were polyphyletic groups, so more recent classifications have expanded Malvaceae to include members of all these families the expanded Malvaceae includes a more morphologically heterogeneous group, including Theobroma cacao (cacao [source of chocolate]), Tilia spp. (linden), Durio zibethinus (durian), and Adansonia spp. (baobab) Malvaceae sensu stricto (mallow family) 78 genera, 1670 spp. distributed widely herbaceous or woody (shrubs) leaves - simple or palmately compound; alternate; stipulate stellate hairs (multi-branched hairs) common on stems and leaves mucilage canals in tissues flowers • actinomorphic • epicalyx (whorl of bracts subtending flower) common • sepals 5 • petals 5 • stamens usually many . monadelphous - filaments fused to form tube around pistil • pistil compound (5 to many carpels); ovary superior • fruit: capsule or schizocarp includes PNW wildflowers (Sphaeralcea spp. - globemallow, Iliamna spp. - globemallow, etc.), food crop (Abelmoschus esculentus - okra), fiber crop (Gossypium hirsutum - cotton), and ornamentals (Hibiscus rosa-sinensis - Chinese hibiscus, Alcea rosea - hollyhock, etc.) Geraniales Geraniaceae (geranium family) 7 genera, 805 spp. distributed in northern and southern temperate zones herbaceous leaves - simple or compound; variously arranged; usually stipulate flowers • actinomorphic or zygomorphic • sepals 5 • petals 5 • stamens 5-15 • pistil compound (5 carpels); ovary superior . carpels surround persistent elongate column • fruit: schizocarp includes PNW wildflowers (Geranium viscosissimum - sticky crane's-bill, etc.), weeds (Geranium robertianum - herb Robert, Erodium cicutarium - common stork's bill, etc.), and ornamentals (Geranium spp. - crane's-bill, Pelargonium spp. - geranium, etc.) Week 6 – Thursday Asterids includes two early-diverging orders and the core Asterids synapomorphies • iridoid compounds - class of monoterpene chemicals used as defense against herbivores • unitegmic ovules - single integument layer; secondary reduction in number of integuments in angiosperms • tenuinucellate ovules - thin nucellus layer around embryo sac Cornales another important family is Hydrangeaceae (hydrangea) Cornaceae (dogwood family) 2 genera, 85 spp. (65 spp. in Cornus) distributed in northern temperate zone woody (trees or shrubs) leaves - simple; usually opposite; secondary veins arch toward leaf apex; spiral thickenings around vessel elements hold leaf together when torn T-shaped hairs (two-branched hairs) on stems and leaves inflorescence • usually corymbose, or capitate (head-like) and subtended by showy bracts flowers • actinomorphic • sepals 4, reduced • petals 4 • stamens 4 • pistil compound (2-3 carpels); ovary inferior • fruit: drupe includes PNW trees, shrubs, and wildflowers (Cornus nuttallii - Pacific dogwood, Cornus sericea - red osier dogwood, Cornus unalaschkensis - western bunchberry), regional food crop (Cornus mas - cornelian cherry), and ornamentals (Cornus florida - flowering dogwood, etc.) Ericales other important families include Sarraceniaceae (New World pitcher-plant), Primulaceae (primrose), and Theaceae (camellia) Polemoniaceae (phlox family) 18 genera, 385 spp. distributed in northern temperate zone and in Andean South America, but especially diverse in western North America herbaceous or woody at base (sub-shrubs) leaves - simple or compound; variously arranged flowers • actinomorphic • sepals 5, fused • petals 5, fused • stamens 5, epipetalous • pistil compound (3 carpels); ovary superior • fruit: capsule includes PNW wildflowers (Phlox spp. - phlox, Polemonium spp. - Jacob's-ladder, Collomia spp., etc.) and ornamentals (Phlox paniculata - garden phlox, etc.) Ericaceae (heather family) 126 genera, 4010 spp. distributed widely, but especially diverse in montane tropics and prominent in boreal to temperate habitats herbaceous or woody (trees or shrubs) leaves - simple; variously arranged; often thick and leathery flowers • actinomorphic or slightly zygomorphic • sepals usually 5 (some 4) • petals usually 5 (some 4), usually fused; often urn-shaped and pendulous or funnel-shaped • stamens usually 10 (some 8), some epipetalous . anthers release pollen via pores at tip (poricidal dehiscence) • pistil compound (usually 3-5 carpels); ovary superior or inferior • fruit: capsule, berry, or drupe strong associations with fungi (mycorrhizae) • some have become parasitic on fungi (mycotrophy) includes PNW trees, shrubs, and wildflowers (Arbutus menziesii - madrone, Gaultheria shallon - salal, Cassiope mertensiana - mountain heather, Arctostaphylos uva-ursi - kinnikinnick, Vaccinium spp. - huckleberry, Rhododendron macrophyllum - Pacific rhododendron, etc.), food crops (Vaccinium corymbosum - blueberry, Vaccinium oxycoccos - cranberry), and ornamentals (Calluna vulgaris - summer heather, Rhododendron spp., etc.) .