Northern Prairie Wildlife Research Center
Aquatic and Wetland Vascular Plants of the Northern Great Plains
31. Onagraceae, the Evening Primrose Family
2. Epilobium L. -- Willow herb
3. Epilobium leptophyllum Raf. -- Narrow-leaved willow herb
Erect perennial 2-8 dm tall, usually simple from the base, branching above,
densely puberulent upward with incurved hairs, producing filiform stolons
at the base in late summer and autumn, the stolons usually reddish, with remote
pairs of minute scales and terminating in ovoid, fleshy turions. Leaves
usually opposite below and alternate above, sessile, linear to linear-lanceolate,
gradually reduced upward, 1-6(7.5) cm long, 1-5(7) mm wide, usually densely
puberulent with incurved hairs, acute to blunt-tipped, revolute, cuneate at
the base. Floral tube 0.8-2 mm long; sepals ovate-lanceolate,
acute, 1.5-4.5 mm long; petals white to pinkish, 3-7 mm long, notched;
pedicels mostly 0.5-2 cm long. Capsules linear, 2.5-8 cm long;
seeds 1-2.2 mm long, the coma white to tawny. Jul--Sep. Shores, stream
banks, springs, fens, seepage areas and ditches, often in shallow water; common
in the n part, less so s; (Que. to B.C., s to NC, OH, MO, KS, CO and WA). E.
palustre L., in part.
E. palustre L., which is very similar to E. leptophyllum,
is reported for Custer and Pennington Counties, SD. The two species are distinguished
as follows:
1 Leaves linear to lanceolate or oblong, subglabrous to sparsely
strigulose above; inflorescence often nodding in bud,
eglandular ................. E. palustre
1 Leaves linear, rarely wider, densely strigulose above;
inflorescence erect or nearly so, often with a mixture of
strigulose and glandular hairs .......... E. leptophyllum
Previous Species -- Epilobium coloratum Biehler
-- Purple-leaved willow herb
Return to Family -- Onagraceae - The
Evening Primrose Family
Next Species -- Ludwigia palustris (L.) Ell. --
Marsh seedbox
U.S. Department of the Interior |
U.S. Geological Survey