Lathyrus sylvestris L. (narrow-leaved vetchling, narrow-leaved everlasting pea)
Map 1764
Plants perennial,
with rhizomes, the roots not producing tubers. Stems
50–200 cm long, trailing or climbing, usually branched, glabrous, conspicuously
winged, the wings 1–3 mm wide. Leaves with 2 leaflets, the petiole
1.5–3.0 cm long, narrowly to relatively broadly winged
winged, the tendrils branched. Stipules 8–14(–23) mm
long, 1–3 mm wide, linear to narrowly lanceolate, the
basal lobe 3–6 mm long, linear to narrowly oblong-triangular. Leaflets 4–11 cm
long, 5–8 mm wide, narrowly lanceolate to narrowly
elliptic, angled at the base, angled to a usually sharply pointed tip, the midvein sometimes extended into a minute sharp point at the
very tip, glabrous, sometimes slightly glaucous.
Inflorescences racemes of 4–9(–12) flowers, the stalk 9–22 cm long, the flower
stalks 8–20 mm long. Calyces with the tube 3–4 mm long, glabrous, the lobes 1–4
mm long, the upper 2 short and triangular, the lowermost lobe about twice as
long as the upper 2, narrowly triangular, the lateral lobes of the lower lip
intermediate in size and shape. Corollas 13–20 mm long, pink
to pinkish or reddish purple. Filaments with the fused portion 9–11 mm
long, the free portion 3–4 mm long. Ovary glabrous.
Fruits 4–7 cm long, 8–9 mm wide, narrowly oblong, flattened, glabrous, 10–20-seeded.
Seeds 3.5–4.0 mm long, more or less globose to
slightly oblong in outline, sometimes slightly flattened,
the surface finely wrinkled, dark brown. 2n=14.
June–August.
Introduced,
uncommon, known thus far only from Franklin County (native of Europe; introduced
and widely scattered in the U.S., Canada). Upland
prairies.
Lathyrus sylvestris similar to L.
latifolius, but is distinguished mainly by its
narrower stipules and smaller flowers. It was first collected in Missouri in
1995 by Doug Ladd as a weed in a constructed prairie at the Shaw Arboretum (now
Shaw Nature Reserve).