BIOL 317: Plant Identification and Classification Summer 2016 - Notes Week 8 – Tuesday • Campanulids • typically have inferior ovary • Dipsacales • another important family is Adoxaceae (elderberry, viburnum) • Caprifoliaceae (honeysuckle family) • 42 genera, 890 spp. • distributed widely, but especially diverse in northern temperate zone • herbaceous or woody (shrubs or vines) • leaves - simple or compound; opposite • flowers • zygomorphic, some weakly so • sepals 5, fused • petals 5, fused § often bilabiate, with 2 upper corolla lobes and 3 lower corolla lobes (notable exception is Lonicera [honeysuckle] which has 4 upper corolla lobes and 1 lower corolla lobe) • stamens 4 or 5, epipetalous • pistil compound (2-5 carpels); ovary inferior § usually with long style and capitate stigma § usually 1 ovule/carpel; in some species, only 1 carpel matures • fruit: capsule, achene, berry, or drupe • Older circumscriptions of Caprifoliaceae, including plants with a woody habit, were paraphyletic with respect to Adoxaceae, Dipsacaceae, and Valerianaceae, families with mostly herbaceous members. In order to make monophyletic families, Sambucus and Viburnum were transferred to Adoxaceae, which all have actinomorphic flowers. Dipsacaceae and Valerianaceae were sunk into Caprifoliaceae in the classification followed here, which creates a family with woody and herbaceous members but all with zygomorphic flowers. Other phylogenetic classifications maintain Dipsacaceae and Valerianaceae, define Caprifoliaceae as a narrower clade, and erect new families Linnaeaceae, Diervillaceae, etc. • includes PNW shrubs and wildflowers (Lonicera ciliosa - orange honeysuckle, Symphoricarpos albus - snowberry, Linnaea borealis - twinflower, Valeriana sitchensis - Sitka valerian, etc.), weeds (Dipsacus fullonum - teasel, etc.), and ornamentals (Weigela sp., Abelia sp., Lonicera japonica - Japanese honeysuckle, Centranthus ruber - red valerian, Scabiosa columbaria - pincushion flower, etc.) • Apiales • another important family is Araliaceae (English-ivy, ginseng) • Apiaceae (carrot family) • 484 genera, 3780 spp. • distributed worldwide, but especially diverse in northern temperate zone • herbaceous • leaves - often compound, some simple; alternate; sheathing base • often aromatic - possess ethereal oils, terpenoids, and other volatile chemicals used for herbivore defense • inflorescence - umbel (pedicels originate from single point and flowers at about the same level); many with compound umbels (umbels of umbels) • flowers • actinomorphic or zygomorphic • sepals 5 • petals 5, free - secondary loss of fusion • stamens 5 • pistil compound (2 carpels); ovary inferior § 1 ovule/carpel § stylopodium - swollen style base secretes nectar • fruit: schizocarp • includes PNW wildflowers (Lomatium spp. - desert-parsley, Sanicula spp. - sanicle, Heracleum maximum - cow-parsnip, Angelica spp., etc.), weeds (Conium maculatum - poison-hemlock, etc.), food crops, herbs, and spices (Daucus carota - carrot, Pastinaca sativa - parsnip, Apium graveolens - celery, Foeniculum vulgare - fennel, Petroselinum crispum - parsley, Coriandrum sativum - cilantro, coriander, Pimpinella anisum - anise, Cuminum cyminum - cumin, Carum carvi - caraway, etc.), and ornamentals (Eryngium amethistium - sea holly, etc.) • Asterales • often have secondary pollen presentation (also called plunger or brush pollination, or a pollen pump) • Anthers of stamens form tube through which style and stigma grow. Pollen is deposited on outside of immature stigma lobes, where it is presented to pollinators. Later, the stigma lobes mature and open to expose the inner receptive surface. • Campanulaceae (bellflower family) • 84 genera, 2380 spp. • distributed worldwide • most herbaceous, some woody (shrubs) • leaves - simple; alternate • milky latex • flowers • actinomorphic (subfamily Campanuloideae) or zygomorphic (subfamily Lobelioideae) • sepals 5, fused • petals 5, fused § bell- or tube-shaped (subfamily Campanuloideae) § 2- or 1-lipped (subfamily Lobelioideae) • stamens 5 § secondary pollen presentation • anthers held together to form tube around pistil (subfamily Campanuloideae) • anthers fused together (syngenesious) to form tube around pistil (subfamily Lobelioideae) • pistil compound (2-5 carpels); ovary inferior • fruit: capsule or berry • includes PNW wildflowers (Campanula spp. - bellflower, Downingia spp., etc.) and ornamentals (Campanula spp., Lobelia spp., etc.) • Asteraceae/Compositae (sunflower family) • 1620 genera, 23600 spp. - among the two largest families of angiosperms • distributed worldwide • herbaceous or woody (shrubs or trees) • leaves - usually simple, but can be highly dissected; variously arranged • inflorescence - head (capitulum) - sessile flowers densely clustered • subtended by whorl (involucre) of bracts (phyllaries) • discoid head - have only disk florets • ligulate head - have only ligulate florets • radiate head - have ray florets at margin, disk florets in center • flowers • actinomorphic (disk floret) or zygomorphic (ray or ligulate floret) • flowers sometimes individually subtended by bracts on the receptacle (chaff) • sepals none, or 2-many § if present, then highly modified into scales or bristles (pappus) • petals 5, fused § tube-shaped (disk floret) § ligule - expanded single lobe, tongue-shaped (ray or ligulate floret) • stamens 5, epipetalous § secondary pollen presentation - anthers fused together (syngenesious) to form tube around pistil • pistil compound (2 carpels); ovary inferior § 1 ovule/carpel, but only 1 carpel matures • fruit: achene • includes PNW shrubs and wildflowers (Artemisia tridentata - big sagebrush, Balsamorhiza sagitata - arrowleaf balsamroot, Arnica spp., Erigeron spp. - fleabane, etc.), weeds (Taraxacum officinale - dandelion, Centaurea spp. - knapweed, etc.), food crops (Lactuca sativa - lettuce, Cynara cardunculus - artichoke, Helianthus annuus - sunflower), and ornamentals (Chrysanthemum spp., Zinnia spp., Tagetes spp. - marigold, etc.) Invasive Plants • Definition of "invasive species" • non-native species that spreads into wilderness or managed ecosystems, develops self-sustaining populations, and becomes disruptive to those ecosystems • Impacts of invasive plants • competition for resources, including space, light, water, nutrients, and pollinators § e.g. Rubus armeniacus (Himalayan blackberry) and Helix hedera (English-ivy) - spreading growth can smother other plants § e.g. Tamarix ramosissima (saltcedar) - deep roots can lower water table in arid regions • change ecosystem processes, including nutrient cycling, water cycling, fire regime, and soil accretion § e.g. Cytisus scoparius (Scotch broom) - nitrogen-fixer increases nitrogen content of soils and alters what other plants can compete in ecosystem § e.g. Fallopia japonica (Japanese knotweed) - more efficient translocation of nutrients from leaves to rhizomes alters availability of nutrients in riparian ecosystems § e.g. Bromus tectorum (cheatgrass) - annual grass species creates fuel which increases frequency and intensity of fires in arid ecosystems § e.g. Spartina alternifolia (saltmarsh cordgrass) - forms dense stands which can increase rate of soil build-up in wetlands, leading to loss of habitat • allelopathy - secretion or leaching of chemicals into soil which inhibit the growth of other plants § e.g. Alliaria petiolata (garlic mustard) - secretes chemicals which inhibit growth of mycorrhizal fungi required by other plants • hybridization - genetic integrity of native species may be compromised by introduction of genes from invasive species § e.g. invasive Spartina alternifolia and native Spartina foliosa • Spread of species • international travel and the movement of plant species by humans, both on purpose and accidental, vastly increased in frequency after the period of European exploration and colonization starting in the late 15th century § e.g. introduction of plant species to the Hawaiian islands • natural colonization rate: 1/100,000 years • after Polynesian settlement: 1/50,000 years • after European settlement: 1/0.25 years • how invasive species are initially introduced § woody species - 66% of invasive plants • horticulture/landscaping - 82% • agriculture - 14% • erosion control - 3% • accidental - 1% § herbaceous species - 33% of invasive plants • seed contaminant (accidental) - many • Phases of invasion • establishment phase - population is slowly spreading • expansion phase - population dramatically increases in size § causes of expansion: • major disturbance - opens opportunities for population to spread and grow in size, e.g. fire, hurricane • new genotypes - continued introduction of individuals during establishment phase or hybridization between introduced species and other species allows for novel genetic combinations to form that may allow the population to take off • perception - population may be increasing gradually, but is not noticed by people until it reaches a critical mass • saturation phase - population reaches equilibrium in ecosystem and maintains stable size • Common traits of invasive plants • capable of vegetative reproduction • fast growth and quick to reach sexual maturity • long flowering and fruiting time • early seed germination • capable of nitrogen-fixation • Strategies for control of invasive plants • institutional § prediction of potential invasiveness of species and prevention of spread before invasion § control of populations that have already invaded- very difficult • personal § remove invasive species from property § don't