According to observations of naturalists and beekeepers.
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Brassica napus (Oleifera Group) is commonly called rapeseed. It is the third-largest source of vegetable oil in the world (behind palm oil and soybean oil). It is primarily grown as a commercial crop for the production of vegetable oil (rapeseed oil) from its seeds, for production of biodiesel from rapeseed oil, for its young edible leaves or as forage for livestock.
Rapeseed is also used as a cover crop in the US during the winter as it prevents soil erosion, produces large amounts of biomass, suppresses weeds, and can improve soil tilth with its root system. Some cultivars of rapeseed are also used as annual forage and are ready for grazing livestock 80 to 90 days after planting.
This plant is present in at least 51 states/provinces in this country.
Brassica napus grow to 100 cm in height with hairless, fleshy, pinnatifid, and glaucous lower leaves which are stalked whereas the upper leaves have no petioles. Brassica napus can be distinguished from Brassica nigra by the upper leaves which do not clasp the stem, and from Brassica rapa by its smaller petals which are less than 13 mm across.
Rapeseed flowers are yellow and about 17 mm across. They are radial and consist of four petals in a typical cross-form, alternating with four sepals. They have indeterminate racemose flowering starting at the lowest bud and growing upward in the following days. The flowers have two lateral stamens with short filaments, and four median stamens with longer filaments whose anthers split away from the flower's center upon flowering.
It is in flower from May to September. The species is hermaphrodite (has both male and female organs) and is pollinated by Bees. The plant is self-fertile.
Rubus spectabilis (aka: Salmonberry)
Salix lucida (aka: Shining willow, Greenleaf willow, Tail-leaf willow, Whiplash willow, Pacific willow, Lance-leaf willow, Longleaf willow, Red willow, Western shining willow)
Salix scouleriana (aka: Scouler's willow, Upland willow)
Acer circinatum (aka: Vine maple)
Prunus emarginata (aka: Bitter cherry)
Malus fusca (aka: Oregon crab, Oregon crab apple, Pacific crab apple, Western crab apple)
Salix bebbiana (aka: Bebb willow, Beak willow, Beaked willow, Long-beaked willow, Diamond willow, Chaton, Petit Minou, Smooth Bebb willow)
Acer platanoides (aka: Norway maple)
Rubus ursinus (aka: California blackberry, California dewberry, California grapeleaf dewberry, Douglasberry, Pacific blackberry)
Salix lemmonii (aka: Lemmon's willow, Lemmon willow)
Salix planifolia (aka: Diamondleaf willow, Planeleaf willow)
Salix boothii (aka: Booth's willow)
Salix amygdaloides (aka: Peachleaf willow, Peach leaf willow)
Robinia pseudoacacia (aka: Black locust, False acacia, Yellow locust, White locust, Green locust, Post locust, Falsa acacia, Robinia)
Ajuga reptans (aka: Bugle, Blue bugle, Bugleherb, Bugleweed, Carpetweed, Carpet bugleweed, Common bugle, St. Lawrence plant)
Astragalus (aka: Milkvetch, Locoweed, Goat's-thorn)
Rubus laciniatus (aka: Cutleaf blackberry, Evergreen blackberry, Slashed blackberry)
Rhus glabra (aka: Smooth sumac, Common sumac, Rocky Mountain sumac, Red sumac, Western sumac, White sumac)
Salix geyeriana (aka: Geyer willow, Silver willow)
Brassica napus (aka: Rapeseed)
Allium schoenoprasum (aka: Chives)
Sinapis arvensis (aka: Charlock mustard, California rape, Charlock, Corn mustard, Canola, Kaber mustard, Rapeseed mustard)
Prunus serotina (aka: Black cherry, Wild black cherry, Rum cherry, Mountain black cherry, Wild cherry)
Calendula officinalis (aka: Marigold, Calendula, Pot marigold, English marigold)
Prunus virginiana (aka: Chokecherry, Western chokecherry, Common chokecherry, Black chokecherry)
Salix glauca (aka: Grayleaf willow, Gray willow, Gray-leaved willow)
Vaccinium corymbosum (aka: Highbush blueberry, High-bush blueberry, Northern highbush blueberry, Tall blueberry, Rabbiteye blueberry, Blue huckleberry, Tall huckleberry, Swamp huckleberry, High blueberry, Swamp blueberry)
Rubus idaeus (aka: Raspberry, Black-haired red raspberry, Brilliant red raspberry, American red raspberry, Red raspberry, Smoothleaf red raspberry, Wild raspberry, Wild red raspberry, Grayleaf raspberry)
Rubus parviflorus (aka: Thimbleberry, Western thimbleberry)
Salix brachycarpa (aka: Shortfruit willow, Barren-ground willow, Small-fruit sand dune willow, Small-fruit willow)
Amorpha fruticosa (aka: Desert false indigo, False indigo-bush, Bastard indigobush, Indigo Bush)
Brassica rapa (aka: Field mustard, Common mustard, Wild mustard, Wild turnip, Forage turnip, Wild rutabaga, Birdsrape mustard, Rape mustard)
Echium vulgare (aka: Viper's bugloss, Blueweed, Blue thistle)
Salsola kali (aka: Russian thistle, Tumbleweed, Prickly saltwort)
Rubus armeniacus (aka: Himalayan blackberry, Rubus discolor, Rubus procerus)
Agastache foeniculum (aka: Giant hyssop, Blue giant hyssop, Anise hyssop, Fragrant giant hyssop, Lavender giant hyssop)
Chamaenerion angustifolium (aka: Fireweed, Great willowherb, Rosebay willowherb, Saint Anthony's Laurel, French-willow)
Cucumis melo (aka: Cantaloupe, Rockmelon, Sweet melon, Spanspek, Honeydew melon, Honeymelon, Crenshaw, Casaba)
Borago officinalis (aka: Borage, Starflower, Common borage, Cool-tankard, Tailwort)
Cirsium arvense (aka: Creeping Thistle, Canada thistle, Field thistle, California thistle, Lettuce from hell thistle, Corn thistle, Cursed thistle, Green thistle, Hard thistle, Perennial thistle, Prickly thistle, Small-flowered thistle, Way thistle, Stinger-needles)
