Tall Blue Lettuce (Lactuca biennis): blue Minnesota wildflowers

Tall Blue Lettuce

Plant Info
Also known as:	Blue Wood Lettuce
Scientific name:	Lactuca biennis
Family:	Aster (Asteraceae)
Life cycle:	annual, biennial
Origin:	native
Habitat:	shade to part sun; moist woods, thickets
Bloom season:	summer
Plant height:	2 to 7 feet
USDA PLANTS database:	Minnesota county distribution map
Spotted in Ramsey County at:	Long Lake Regional Park Rice Creek Trail Corridor Vadnais/Snail Lake Regional Park

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Flower:: Flowers are in a tightly packed cluster at the top of the plant that spreads out as the plant matures. Smaller clusters develop from the leaf axils near the top of the plant. Individual flowers are about ¼ inch across with 15 to 30 pale blue to whitish petals and numerous stamen with curly blue tips.
Leaves and stem:: Leaves become progressively smaller as they ascend the stem. Those near the base of the plant are up to 12 inches long and 6 inches wide, deeply divided into several wide coarsely toothed lobes with pointed tips. They are roughly triangular or arrow-head shaped in outline, with “winged” leaf stems. Towards the top of the plant the lobes are fewer and narrower, and leaves have little or no leaf stem. All leaves are hairy, especially the underside. Attachment is alternate.The main stem is hairy and often tinged or spotted purple.
Fruit:: The seed head is about 1 inch in diameter; each seed has a tuft of tan fluff to carry it off in the wind.
Notes:: Tall Blue Lettuce is similar to Wild Lettuce. The latter has hairless leaves that change shape as the ascend the stem. The leaves of Tall Blue Lettuce are hairy and the lobed leaves just become smaller.