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.
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)
Prunus pumila (aka: Sandcherry, Western sandcherry, Eastern sandcherry, Great Lakes sandcherry)
Salix arbusculoides (aka: Littletree willow)
Salix bebbiana (aka: Bebb willow, Beak willow, Beaked willow, Long-beaked willow, Diamond willow, Chaton, Petit Minou, Smooth Bebb willow)
Prunus americana (aka: American plum, Goose plum, River plum, Wild plum)
Salix planifolia (aka: Diamondleaf willow, Planeleaf willow)
Acer spicatum (aka: Mountain maple, Low maple, Moose maple, Water maple, Plaine batarde, Fouereux)
Astragalus (aka: Milkvetch, Locoweed, Goat's-thorn)
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)
Rhus glabra (aka: Smooth sumac, Common sumac, Rocky Mountain sumac, Red sumac, Western sumac, White sumac)
Salix lutea (aka: Yellow willow)
Allium schoenoprasum (aka: Chives)
Brassica napus (aka: Rapeseed)
Sinapis arvensis (aka: Charlock mustard, California rape, Charlock, Corn mustard, Canola, Kaber mustard, Rapeseed mustard)
Prunus pensylvanica (aka: Pin cherry, Fire cherry, Bird cherry)
Prunus virginiana (aka: Chokecherry, Western chokecherry, Common chokecherry, Black chokecherry)
Rhamnus cathartica (aka: Common buckthorn, European buckthorn, Dahurian buckthorn)
Salix myrtillifolia (aka: Blueberry willow, Low blueberry willow, Tall blueberry willow)
Salix glauca (aka: Grayleaf willow, Gray willow, Gray-leaved willow)
Tilia americana (aka: American basswood, Basswood, Linden)
Salix brachycarpa (aka: Shortfruit willow, Barren-ground willow, Small-fruit sand dune willow, Small-fruit willow)
Brassica rapa (aka: Field mustard, Common mustard, Wild mustard, Wild turnip, Forage turnip, Wild rutabaga, Birdsrape mustard, Rape mustard)
Asclepias syriaca (aka: Сommon milkweed, Butterfly flower, Silkweed, Silky swallow-wort, Virginia silkweed)
Echium vulgare (aka: Viper's bugloss, Blueweed, Blue thistle)
Chamaenerion angustifolium (aka: Fireweed, Great willowherb, Rosebay willowherb, Saint Anthony's Laurel, French-willow)
Agastache foeniculum (aka: Giant hyssop, Blue giant hyssop, Anise hyssop, Fragrant giant hyssop, Lavender giant hyssop)
Borago officinalis (aka: Borage, Starflower, Common borage, Cool-tankard, Tailwort)
Diervilla lonicera (aka: Northern bush honeysuckle, Bush-honeysuckle, Dwarf bush-honeysuckle, Herbe bleue)
Rubus chamaemorus (aka: Cloudberry, Bake apple, Baked apple berry, Bakeapple, Nordic berry, Knotberry, Aqpik, Low-bush salmonberry, Averin, Evron)
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)
