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Prenanthes altissima L.

Nabalus altissimus (L.) Hook.

Prenanthes altissima L. var. cinnamomea Fernald

Tall white lettuce, rattlesnake root

KingdomPlantaePlants, but not fungi, lichens, or algae
SubkingdomTracheobiontaVascular plants—plants with a “circulatory system” for delivering water and nutrients
DivisionMagnoliophytaFlowering plants, also known as angiosperms
ClassMagnoliopsidaDicotyledons—plants with two initial seed leaves
SubclassAsteridaeA large class that encompasses asters
OrderAsteralesFlowering plants with a central disk flower and surrounding petals, like daisies
FamilyAsteraceaeThe aster family, which also includes daisies and sunflowers; from the Greek ἀστήρ, “star,” for the star-shaped flowers
GenusPrenanthesFrom Greek prenes, “prone, prostrate, with face downward,” and anthos, “flower”
Speciesaltissima“Very tall, tallest”

About plant names...

Tall white lettuce is a North American native. It prefers moist habitats, and mountainsides, forests, and woodlands.

Plants: A stout central stem is glabrous, light green to mottled purple to purple, and 12-79" (30-200 cm) tall. Much smaller green side branches support a few leaves and the flowers.

Leaves: Alternate, 1½-7" (4-17 cm) around, and hairless. Torn leaves produce a white latex. Leaf shapes are highly variable: triangular, heart-shaped, 3-5 lobed, with a couple of coarse teeth or smooth-edges. Lower leaves have longer stems (petioles), and they are winged.

Flowers: Most members of the aster family are composite flowers, meaning they have both ray and disk florets. This species, however, has only ray flowers. Each flower is tubular, downward-hanging, with 5 petals, cream tinged with green to straw yellow in color. Flowers are ¾" (1.9 cm) long × ½" (1.3 cm) around, and emerging from the center of each about ½" (1.3 cm) are several stamens. Flowers appear from August to November.

Fruits: Fruits (if you want to get technical, they are called cypselae for plants in the aster family) are ⅛-³/₁₆" (3.5-6 mm) long, and tan to brown, with 8-11 ribs.

Edibility: Very young basal leaves are edible.

Online References:

Prenanthes altissima at Illinois Wildflowers

Prenanthes altissima on gobotany.nativeplanttrust.org

Prenanthes altissima on Ontario Wildflowers

Prenanthes altissima on nametheplant.net (Native & Naturalized Plants of the Carolinas and Georgia)

Prenanthes altissima on eFloras

Prenanthes altissima on michiganflora.net

References:

Weakley, Alan S.; Ludwig, J. Christopher; Townsend, John F.; Crowder, Bland (Ed.), Flora of Virginia, Botanical Research Institute of Texas Press, 2013, p. 359

Prenanthes altissima (tall white lettuce, rattlesnake root)

7/31/2012 · Bemis Rd Conservation Area, Pepperell, MA
≈ 14 × 21" (34 × 52 cm) ID is uncertain

Prenanthes altissima (tall white lettuce, rattlesnake root)

8/19/2010 · Nashua River Rail Trail, Groton, MA
≈ 6 × 4" (15 × 10 cm) ID is uncertain

Prenanthes altissima (tall white lettuce, rattlesnake root)

9/26/2010 · Brooks Woodland Preserve, Swift River Tract, Petersham, MA
≈ 7 × 11" (18 × 27 cm) ID is uncertain

Prenanthes altissima description by Thomas H. Kent, last updated 25 May 2020.

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Prenanthes altissima (tall white lettuce, rattlesnake root)

8/19/2010 · Nashua River Rail Trail, Groton, MA
≈ 8 × 5" (19 × 13 cm) ID is uncertain

Prenanthes altissima (tall white lettuce, rattlesnake root)

9/26/2010 · Brooks Woodland Preserve, Swift River Tract, Petersham, MA
≈ 8 × 12" (20 × 31 cm) ID is uncertain

Prenanthes altissima (tall white lettuce, rattlesnake root)

7/31/2012 · Bemis Rd Conservation Area, Pepperell, MA
≈ 14 × 21" (34 × 52 cm) ID is uncertain

Prenanthes altissima (tall white lettuce, rattlesnake root)

8/19/2010 · Nashua River Rail Trail, Groton, MA
≈ 1½ × 1½" (3.9 × 4 cm) ID is uncertain

Prenanthes altissima (tall white lettuce, rattlesnake root)

8/19/2010 · Nashua River Rail Trail, Groton, MA
≈ 3½ × 2½" (9.8 × 6.6 cm) ID is uncertain

Prenanthes altissima (tall white lettuce, rattlesnake root)

9/26/2010 · Brooks Woodland Preserve, Swift River Tract, Petersham, MA
≈ 7 × 11" (18 × 27 cm) ID is uncertain

Range: Zones 4-8:

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