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The Eudicots, or "true" dicots, form a monophyletic group. Members share the morphological synapomorphy of tricolpate pollen or derivitives thereof (the ancestral state of angiosperms, retained by monocots and basal angiosperm lineages, is monosulcate or monoporate pollen). Although most eudicots have flower parts in multiples of 4 or 5, lineages of Eudicots that branched off before the Rosid/Asterid/Caryophyllales split sometimes show ancestral floral characteristics; these lineages are collectively known as the Basal Eudicots, although they are a paraphyletic group of successive branches (only 2 shown below). They often have numerous stamens, separate carpels, and other characteristics more typical of the Basal Angiosperm lineages, and they may have flower parts in multiples of 6 or indeterminate as well as 4 or 5. Some of these plants were once grouped along with the Basal Angiosperms by traditional taxonomists for these reasons, although molecular evidence now supports their placement with other true dicots as does their tricolpate pollen.

Basal eudicot families covered in class:

Ranunculales:

Berberidaceae (Barberry Family)

Papaveraceae (Papaveraceae Family)

Ranunculaceae (Buttercup Family)

Proteales:

Nelumbonaceae (Lotus Family)

Platanaceae (Sycamore Family)

 

Order: Ranunculales

*Berberidaceae: (Barberry Family)

Identification characteristics: Berberidaceae have 4 to 6 sepals which are often caducous (deciduous when the flower opens); thus, open flowers of Berberidaceae may look sepal-less, but the sepals will be present on flower buds. Petals are 6 or 8 or 12, rarely more in multiples thereof. Stamens are usually 6, 8, or 12, but sometimes a few extra may be present. The anthers usually open by two flaps that open from the base, but Podophyllum retains typical longitudinal dehiscence. There is one superior ovary formed from one carpel (one locule). The fruit is usually a berry (exception in Jeffersonia is a pyxidium- a capsular structure that opens via a lid). Many Berberidaceae are planted as ornamental shrubs, but native species in the E. U.S. are all herbaceous except the rare Berberis canadensis.

Interesting stuff: Berberidaceae are spring and early-summer bloomers in our area. Many are poisonous. Shrubs such as Nandina, Mahonia, and Berberis are often planted as ornamentals. European barberry was once widely planted and escaped in the U.S., but it serves as the alternate host of wheat stem rust, and massive removal projects were undertaken last century. Native barberry is now rare in many places due to this eradication project and competition from other introduced, invasive species.

Examples: Caulophyllum thalictroides (habit 1), (habit 2), (flower closeup), (yellow form), (2), (3) Blue Cohosh; Diphyllea cymosa (inflorescence), (2), (flower), (2), (in fruit), (2) Umbrella Leaf; Jeffersonia diphylla (habit in flower), (flowers), (flower closeup), (habit), (fruit) Twinleaf; Podophyllum peltatum (flower closeup) Mayapple; Vancouveria hexandra White Inside-out Flower

*Papaveraceae: (Poppy Family)

Identification characteristics: Papaveraceae have 2 sepals which are soon caducous. Most have 4 petals that are radially symmetric, but multiples of 4 also occur. Stamens are numerous in the typical members of the family. Members of the lineage formerly separated as Fumariaceae have highly zygomorphic or bis-bilaterally symmetric (2 unequal planes of symmetry- see Adlumia and Dicentra) flowers, the petals often being somewhat connivent. Stamens in typical Papaveraceae are very numerous (6, diadelphous, grouped in two sets of three in Fumarioids). There is one superior ovary. Papaveraceae have alternate leaves that may be simple to deeply dissected, and members outside of Fumariodeae have white to colorful sap.

Interesting stuff: Members of Papaveraceae (including Fumariaceae) produce isoquinone alkaloids that are often very toxic or otherwise induce profound physiological effect. The most economically important example by far is the opium poppy (Papaver somniferum), extracts of which are the basis for opium, morphine, and other derived drugs. The seeds of P. somniferum, which contain only trace amounts of alkaloids, are the poppy seeds commonly used in baked goods. Many Papaveraceae are colorful garden ornamentals. Note: Fumariaceae are listed as a separate family in your manual.

Argemone albiflora White Prickly-Poppy; Sanguinaria canadensis (patch), (individual), (2), (flower closeup), (2), (another patch), (2), (fruit) Bloodroot; Stylophorum diphyllum, (flower closeup), (2), (3), (fruit) Wood Poppy

(subfamily Fumarioideae): Adlumia fungosa Allegheny Vine; Corydalis flavula (flower, side), (front), (population) Yellow Fumewort; C. sempervirens Rock Harlequin; Dicentra canadensis Squirrel Corn; D. cucullaria (flowers closeup), (habit), (more habit), (3) Dutchman's Breeches; D. eximia Wild Bleeding-Heart

*Ranunculaceae: (Buttercup Family)

Identification characteristics: Floral morphology in Ranunculaceae is highly variable, and a suite of characters must be examined for identification. Species are predominantly herbs (often vines in Clematis). They have alternate (or basal) leaves (opposite in Clematis). Usually flowers are radially symmetric (see Delphinium tricorne for an exception). Sepals are usually 5 (4 in Clematis, indeterminant in many others). They are often petaloid and are the pollinator attractant when petals are absent. Sometimes a combination of sepals and petals make up the colorful floral display (see Delphinium). Petals are usually 5 when present, and may have nectar glands at their base, sometimes held within an elaborated spur (see Delphinium and Aquilegia canadensis below for examples). Stamens are numerous in all cases. Ovaries are superior and apocarpous (separate), sometimes 5, often more numerous. An important characteristic in keys is whether each carpel contains one or numerous ovules, and thus forms an achene or follicle, respectively. Some multi-ovule carpels occasionally form berries rather than follicles.

Interesting stuff: Like other Ranunculalean families, Ranunculaceae often produce very toxic alkaloids. The family provides numerous ornamentals, such as Larkspurs (Delphinium), Monkshoods (Aconitum), Columbines (Aquilegia), and Windflowers (Anemone). Some Ranunculaceae have reduced perianth parts and rely instead on brightly colored stamens to attract pollinators (see Hydrastis canadensis and Thalictrum pubescens). Occasionally, Ranunculaceae are dioecious (see Clematis virginiana and Thalictrum dioicum) and/or wind pollinated (T. dioicum). Most Ranunculaceae bloom in spring and make up a significant portion of the spring flora in the eastern U.S.

Examples: Aconitum columbianum Western Monkshood; A. reclinatum Trailing Monkshood; Actaea alba, (inflorescence) (infructescence) White Baneberry; Anemonella (Thalictrum) thalictroides, (2), (3), (4), (pink form) Rue Anemone; Anemone multifida Cut-leaved Anemone; A. quinquefolia Wood Anemone; A. virginiana, (flower closeup) Thimbleweed; Aquilegia canadensis, (flower), (flower 2), (flower 3) Wild Columbine; Caltha palustris Marsh Marigold; Cimicifuga racemosa Black Cohosh; Clematis occidentalis, (flower) Purple Clematis; C. ochroleuca Curlyheads; C. pitcheri, (flower) Texas Leatherflower (photo from TX), C. viorna Leatherflower; C. virginiana (male) Virgin's Bower; Coptis groenlandica, (closer) Goldthread; Delphinium carolinianum (2), (3) Prairie Larkspur; D. tricorne (2), (3), (flower) Dwarf Larkspur; Hepatica americana (white and pink), (purple and white), (pale lavender), (purple), (white) Round-Lobed Hepatica; H. acutiloba (2), (3), (4), (5) Sharp-Lobed Hepatica; Hydrastis canadensis, (2), (3), (individual), (closeup), (2), (fruit), (closer) Goldenseal; Isopyrum biternatum False Rue Anemone; R. abortivus Littleleaf Buttercup; Ranunculus fascicularis Early Buttercup; R. ficaria Lesser Celandine; Thalictrum clavatum Mountain Meadow Rue; T. dioicum (female), (close), (male inflorescence) Early Meadow Rue; T. pubescens, (flower closeup) Tall Meadow Rue; Trautvetteria caroliniensis (2), (3) Tassel-rue; Trollius laxus, (flower), (ssp. albiflorus) Spreading Globeflower

Menispermaceae: Menispermum canadense (male), (male closeup), (female), (female closeup), (fruits) Moonseed

 

Order: Proteales

*Nelumbonaceae: (Water Lotus Family)

Identification characteristics: The most likely family to be confused with Nelumbonaceae is the unrelated Nymphaeaceae. Both families are aquatics with roundish leaves on long petioles and numerous tepals and stamens. Many differences exist between the two families, however. Despite the fact that most traditional taxonomic treatments tentatively grouped Nelumbo within the Nymphaeles, it came as no surprise that it actually belongs within the eudicots. Aside from having a very different gynoecial structure from Nymphaeales, Nelumbo also had tricolpate pollen like a good eudicot should (very much different from the "primitive" monosulcate pollen found in Nymphaeales and other basal angiosperms). The leaves of Nelumbo are large, orbicular, peltate, and always held well above the water surface. The gynoecium and fruit of Nelumbo are particularly unusual, consisting of numerous distinct carpels imbedded in a large, obconic, flat-topped receptacle.

Interesting stuff: Only two extant species of Nelumbo exist: Nelumbo lutea (below), which is native to the northern midwest of the United States, and Nelumbo nucifera, the Sacred Lotus of Asia. The Sacred Lotus is an important symbol of purity in Buddhism. Both lotus species and hybrid cultivars are widely planted as ornamentals in water gardens, and lotus seeds are sometimes roasted and eaten. The leaves are coated by a waxy substance that prevents mud from adhering to the leaf surface upon emergence and causes water to bead up in droplets on the leaf. This wax has even bee extracted and used in some types of paints and sealants as a waterproofing agent. The pitted seed receptacles of lotuses are often dried and sold for use in floral arrangements.

Nelumbo lutea, (habit), (fruit) American Water Lotus, Nelumbo hybrid Hybrid Water Lotus

*Platanaceae: (Sycamore Family)

Identification characteristics: The most distinctive feature of the family, containing only the tree genus Platanus, is the mottled bark, which flakes off leaving various shades of greenish, yellowish, and brown on the lower trunk and whitish on the upper trunk and branches. The lateral buds are surrounded by the petiole. The plants are monoecious, and the flowers are small, inconspicuous, and wind-pollinated. The flowers are borne in dense, globular heads as the trees leaf out in early spring. Sepals are very minute and are variable in number, ranging from 3 to 7. Male flowers have the same number of petals, but these are lacking in female flowers. The anther connectives are elaborated into a long, peltate structure. Female flowers produce a 5 to 9 parted apocarpous gynoecium that will mature to separate achenes, each subtended by long bristles. These thin achenes are aggregated into a conspicuous globose cluster about 1 to 1.5 inches thick.

Interesting stuff: Sycamore trees usually occur along streams, rivers, and bottomland floodplains where their massive form and ghostly white upper bark make them a conspicuous and easily-identified tree. They are also commonly planted as street and shade trees, although their messy, ever-flaking bark is disdained by many.

Platanus occidentalis (branch with male and female inflorescences), (female inflorescence), (male inflorescence), (male inflorescence dehiscing wind-borne pollen) American Sycamore

Proteaceae: Embothrium coccineum Chilean Firebush

 

Order: Buxales

Buxaceae: Pachysandra procumbens (inflorescence) Allegheny Spurge

 

 

 

 

 



 

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