BIOL 317: Plant Identification and Classification Summer 2016 - Notes
Week 4 – Tuesday • Wind-pollination - selective factors and morphological effects • No need to attract animal pollinators • flowers with reduced or no perianth • small flowers • Pollen transfer is not directed – most pollen will not successfully reach stigma of same species • many flowers • high pollen:ovule ratio § unisexual flowers – having more staminate flowers than pistillate flowers is one strategy to achieve a high pollen:ovule ratio • feather stigma - to capture pollen in air
Monocots (continued) • Typhaceae (cattail family) • 2 genera, 25 spp. • distributed worldwide; aquatic • herbaceous • leaves - simple; alternate and 2-ranked; linear • rhizomatous • inflorescence • dense spike (Typha) or heads (Sparganium) - sessile flowers § male flowers at top, female flowers at bottom • flowers • flowers unisexual - plants monoecious • actinomorphic • tepals 1-many - reduced to scales or bristles • stamens 1-8 • pistil compound (3 carpels, 1 ovule total); ovary superior • fruit: achene-like follicle or drupe
• Juncaceae (rush family) • 7 genera, 430 spp. • distributed widely, especially diverse in temperate regions, often in wetlands • herbaceous • leaves - simple; basal or alternate, 3-ranked; linear or cylindrical; open or closed sheath • often rhizomatous • stem - round and solid
• flowers • actinomorphic • tepals 6, scarious (thin and dry) and persistent • stamens 6 • pistil compound (3 carpels); ovary superior • fruit: capsule
• Cyperaceae (sedge family) • 98 genera, 5430 spp. • distributed widely, often in wetlands • herbaceous • leaves - simple; basal or alternate, 3-ranked; linear or cylindrical; closed sheath • often rhizomatous • stem – usually triangular and solid, but some are round • inflorescence • spikelet, usually subtended by 1 bract, usually part of larger inflorescence • flowers • subtended by 1 bract • actinomorphic • tepals 0, or 3-6 reduced to scales or bristles • stamens 1-3 • pistil compound (usually 3 carpels, 1 ovule total); ovary superior • fruit: achene • genus Carex – largest genus in family and among largest genera of angiosperms, ~1800 spp. • perigynium – bottle-shaped bract surrounding female flower • ligule – flap of tissue on inner surface of leaf where blade meets sheath • flowers usually unisexual, on monoecious plants
• Poaceae/Gramineae (grass family) • 707 genera, 11337 spp. (fifth largest angiosperm family) • most economically-important family as source of food and ecologically important as dominant members of grassland ecosystems • distributed worldwide, often in drier habitats • herbaceous • leaves - simple; basal or alternate, 2-ranked; linear; usually open sheath • ligule – flap of tissue on inner surface of leaf where blade meets sheath • often rhizomatous or stoloniferous • stem (culm) – usually round and hollow at internodes • swollen nodes – gives stem jointed appearance • intercalary meristem – stem cells at base of leaf blades, leaf sheaths, and nodes allow for regrowth after leaf and shoot tips have been grazed/mown
• inflorescence • spikelet, usually subtended by 2 bracts (glumes), usually part of larger inflorescence • flowers (florets) • subtended by 2 bracts – lemma (outer, larger bract) and palea (inner, smaller bract) • zygomorphic • tepals 2, reduced to small scales (lodicules) • stamens 3 • pistil compound (usually 3 carpels, 1 ovule total); ovary superior • fruit: caryopsis (achene in which fruit wall is fused to seed coat) • grain terminology § chaff - bracts (glumes, lemma, palea) § grain - fruit (caryopsis) § bran - fruit wall/seed coat of caryopsis § germ - embryo in seed § endosperm - starch and proteins remaining after processing in refined grains, the majority of what we eat
Juncaceae Cyperaceae Poaceae Leaves closed or open closed sheath; ligule open sheath; sheath; ligule absent present only in Carex ligule present Stem round and solid triangular or round, round and hollow and solid Perianth 6 tepals none or reduced reduced Fruit capsule achene caryopsis (achene)
• Trends in angiosperm floral evolution (ancestral state èderived) • radial symmetry è bilateral • large number of organs è small and set number of organs • spiral arrangement è whorled • organs free è fused • perianth undifferentiated (tepals) è perianth differentiated into sepals and petals • stamens undifferentiated (laminar) è stamens differentiated into filament and anther • ovary superior è inferior • flowers perfect è unisexual
ANA grade • paraphyletic group (grade) comprising three clades (~175 spp. total) • Amborellaceae – includes only one species Amborella trichopoda • Nymphaeales – includes Nymphaeaceae • Austrobaileyales – includes 3 families: Schisandraceae (including the former Illiciaceae – star-anise), Trimeniaceae, and Austrobaileyaceae • mostly tropical and subtropical plants that have retained many ancestral character states
• Nymphaeaceae (water-lily family) • 3 genera, 58 spp. • distributed widely in aquatic habitats • herbaceous • leaves - simple; variously arranged; peltate or subpeltate • rhizomatous • flowers • actinomorphic • sepals 4-12 • petals usually many; intergrades with stamens • stamens usually many; often laminar • pistil usually compound (usually many carpels); ovary superior or inferior • fruit: berry or capsule
Magnoliids • clade comprising four orders (~10,000 spp. total, 3.3% of angiosperms) • mostly tropical, subtropical, and warm-temperate plants that have retained many ancestral character states • ethereal oils (aromatic terpenoids) common, giving plants a "primitive odor" (also found in Austrobaileyales); function as defense against herbivores • other important families include Annonaceae (cherimoya, soursop, pawpaw), Myristacaceae (nutmeg), Lauraceae (bay laurel), and Piperaceae (black pepper)
• Magnoliaceae (magnolia family) • 2 genera, 227 spp. • distributed in eastern Asia, eastern North America, and tropical South America • woody (mostly trees) • leaves - simple; alternate; sheathing stipule • flowers • actinomorphic • tepals 6 to many • stamens many, laminar • pistils simple, many; ovary superior • elongate receptacle • fruit: aggregate of follicles (Magnolia) or samaras (Liriodenderon) Week 4 – Thursday Eudicots/Tricolpates • includes ~75% of angiosperms • shared traits • tricolpate pollen (3 apertures/openings) § ancestral state is monosulcate pollen (1 aperture), found in most angiosperms outside the eudicots • perianth differentiated into sepals and petals • perianth organs in whorls, rather than spirally arranged • stamens differentiated into anther and filament • perianth organs in multiples of four or five (4- or 5-merous)
"Basal eudicots" • paraphyletic group comprising about four orders • other important families include Papaveraceae (poppy), Berberidaceae (barberry, Oregon grape), Proteaceae (protea), and Platanaceae (sycamore)
• Ranunculaceae (buttercup family) • 62 genera, 2525 spp. • distributed widely, especially diverse in the northern temperate zone • usually herbaceous; some vines and shrubs • leaves – simple or compound, margin often toothed; variously arranged; usually no stipules • flowers • actinomorphic or zygomorphic • sepals usually 5, often showy • petals usually 5 • stamens many • pistils simple, usually several to many; ovary superior • fruit: aggregate of follicles, achenes, or berries • includes PNW wildflowers (Aquilegia spp. - columbine, Delphinium spp. - larkspur, Anemone spp., etc.) and ornamentals (Helleborus spp. – Lenten rose, Clematis spp., etc.)
Core eudicots • morphologically heterogeneous clade
Saxifragales • basally fused carpels common • hypanthium common • other important families include Hamamelidaceae (witch-hazel), Paeoniaceae (peony), and Grossulariaceae (currant)
• Saxifragaceae (saxifrage family) • 33 genera, 600 spp. • distributed in northern temperate zone and adjacent montane areas; especially diverse in western North America • herbaceous • leaves – simple or compound; often basal or alternate; usually no stipules • flowers • usually actinomorphic, some zygomorphic • hypanthium (usually cup-shaped structure formed by fusion of base of sepals, petals, and stamens) • sepals usually 5 • petals usually 5 • stamens 5 or 10 • pistils simple, usually 2, basally fused; or compound (usually 2 carpels); amount of fusion at carpel base varies; ovary superior to inferior • fruit: 2 follicles or septicidal capsule • includes PNW wildflowers (Tellima grandiflora - fringecup, Micranthes spp. - saxifrages, Heuchera spp. - alumroot, etc.) and ornamentals (Astilbe spp., Heuchera spp., etc.) • Crassulaceae (stonecrop family) • 34 genera, 1400 spp. • distributed widely, usually in arid habitats • herbaceous or shrubby; succulent (leaves and stems thickened and fleshy to store water) • crassulacean acid metabolism (CAM) – a form of photosynthesis in which stomata open and allow carbon dioxide to be fixed at night and fixed carbon is converted to sugars using sunlight during the day. Thus, stomata can remain closed during the day to reduce water loss. • leaves - simple; variously arranged • flowers • actinomorphic • sepals 4 or 5 • petals 4 or 5 • stamens 4, 5, 8, or 10 • pistil simple, 4 or 5, basally fused; or compound (4-5 carpels); amount of fusion at carpel base varies; ovary superior • fruit: aggregate of follicles • includes PNW wildflowers (Sedum spp. – stonecrops) and ornamentals (Crassula ovata – jade plant, Kalanchoe spp., etc.)
Wind-pollinated woody plants • Common traits: • flowers do not attract animal pollinators • reduced or no perianth • small • no reward • high pollen:ovule ratio • large number of flowers • unisexual flowers, with more staminate than pistillate flowers • stigmas large and plumose or papillate • inflorescence: catkins (ament) – usually pendulous spike of unisexual inconspicuous flowers • flowers emerge before leaves • Wind-pollinated woody plants once were thought to be primitive and form a clade (“Amentiferae”) • wind-pollination now known to have evolved independently multiple times from animal-pollinated ancestors
Rosids • morphologically heterogeneous clade • comprises two large clades: fabids and malvids
Fabids • morphologically heterogeneous clade
• Fagales • common traits: • woody • unisexual flowers, monoecious plants • perianth reduced or none • staminate flowers in catkins • ovary inferior • fruit indehiscent • another important family is Juglandaceae (walnut)
• Fagaceae (oak family) • 7 genera, 670 spp. • distributed in northern temperate and subtropical zone • woody (trees and shrubs) • leaves - simple; alternate; stipules • inflorescence • staminate flowers in small groups subtended by bract, on catkin • pistillate flowers in small groups (1-3), subtended by cupule (involucre/whorl of bracts) • flowers • unisexual, plant monoecious • actinomorphic • tepals 6, reduced • stamens 4-many • pistil compound (3 carpels, 1 ovule total); ovary inferior • fruit: nut (dry indehiscent one-seeded fruit with thick, hard fruit wall), surrounded by cupule • includes PNW tree (Quercus garryana – Garry oak), food crop (Castanea sativa - chestnut), timber species (Quercus spp. – oak, Quercus suber – cork), and ornamentals (Fagus spp. – beeches, Quercus spp., etc.)
• Betulaceae (birch family) • 6 genera, 145 spp. • distributed in northern temperate zone • woody (trees and shrubs) • leaves - simple; alternate; stipules; margins doubly-serrate
• inflorescence • staminate flowers in small groups subtended by bract, on catkin • pistillate flowers in small groups subtended by bract, usually on catkin § Corylus (hazel) is an exception, with pistilate flowers in small groups, not on catkin • flowers • unisexual, plant monoecious • actinomorphic • tepals none or 1-4, reduced • stamens usually 1-4 • pistil compound (2 carpels, 1 ovule total); ovary inferior • fruit: achene, nut, samara • includes PNW trees (Alnus spp. – alders, Betula spp. – birches, Corylus cornuta - hazel), food crop (Corylus avellana – hazelnut), and ornamentals (Betula spp. – birches, Carpinus spp. – hornbeams, etc.)
• Malpighiales
• Salicaceae • former family Flacourtiaceae is paraphyletic with respect to Salicaceae sensu stricto [s.s.] (in the narrow sense), so Salicaceae was expanded to encompass both families • the larger Salicaceae (sensu lato [s.l.] – in the broad sense) is morphologically heterogeneous and includes many tropical species
• Salicaceae s.s (willow family) • 2 genera, 485 spp. • distributed in northern temperate zone • woody (trees and shrubs) • leaves - simple; alternate; stipules; usually serrate with salicoid teeth (vein ends at tooth tip and forms a small gland) • inflorescence • staminate flowers individually subtended by often hairy bract, on catkin • pistillate flowers individually subtended by often hairy bract, on catkin • flowers • unisexual, plant dioecious • actinomorphic • perianth none • stamens 2-8 • pistil compound (2-4 carpels); ovary superior • fruit: capsule • seeds usually hairy • includes PNW trees (Populus trichocarpa – black cottonwood, Populus tremuloides – aspen, Salix spp. - willows), timber and pulp crops (Populus spp. – poplars), and ornamentals (Populus spp., Salix spp.)