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Aquatic and Wetland Vascular Plants of the Northern Great Plains

Epilobium L. -- Willow herb


Fibrous-rooted perennial herbs (those included here), often producing leafy rosettes or subterranean turions from the base late in the growing season, these sessile or on lateral rhizomes or stolons. Leaves simple, opposite, alternate or usually opposite below and becoming alternate above, sessile or short-petioled, exstipulate. Flowers small, white to pink, solitary in the axils of upper reduced leaves, arranged in simple or branched, terminal racemes. Floral tube short or absent; sepals 4; petals 4, white to pink, notched at the tip; stamens 8, in 2 series of 4, the inner 4 stamens much shorter than the outer 4; stigma sessile, undivided, ovary linear-elongate, appearing like a continuation of the pedicel, 4-celled, maturing into a linear, 4-valved capsule, splitting from the tip to release numerous brown, ellipsoid seeds which bear a terminal tuft of fine hairs (the coma).

References:

Hoch, P. C. Epilobium, In The Flora of the Great Plains.  The 
     Great Plains Flora Association.  Univ. Press of Kansas. 1986. 

Hoch, P. C. and P. H. Raven.  1977.  New combinations in Epilobium 	
     (Onagraceae).  Ann. Missouri Bot. Gard. 64:136. 

Munz, P. A. 1965. Epilobium.  In North Amer. Flora Ser. II.  Part 5.
     New York Bot. Gard. 198-225.

Lead Characteristic Go To
1 Leaves linear to linear-lanceolate, 1-5(7) mm wide, the margins entire, revolute. E. leptophyllum
1 Leaves lanceolate to ovate-lanceolate, mostly 0.8-3 cm wide, the margins shallowly serrate, not revolute. Lead 2
2 Leaves acute or acuminate to a rather blunt tip, each margin with mostly 15-30 teeth or fewer; flower buds obtuse to rounded or slightly pointed at the tip; coma white or nearly so, attached to a short, broad, flattened beak at the tip of the seed. E. ciliatum
2 Leaves long-acuminate to a slender, pointed tip, each margin of the main cauline leaves mostly with 30-75 teeth; flower buds tipped with the 4 projecting or divergent sepal tips; coma cinnamon-colored at maturity, sessile on the beakless rounded tip of the seed. E. coloratum


31. Onagraceae, the Evening Primrose Family
2. Epilobium L. -- Willow herb
1. Epilobium ciliatum Raf.
2. Epilobium coloratum Biehler -- Purple-leaved willow herb
3. Epilobium leptophyllum Raf. -- Narrow-leaved willow herb


Return to Family -- Lythraceae - The Loosestrife Family
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