A beautiful European import that has made itself at home in our swamps and marshes, but has not made a pest of itself. These plants were blooming in a swamp  in Frick Park in the middle of May. it took a bit of trudging through muck to get this photograph, but it was worth the muddy shoes.

Gray describes the genus and the species:

ÌRIS [Tourn.] L. FLEUR-DE-LIS. Tube of the flower more or less prolonged beyond the ovary. Stamens distinct; the oblong or linear anthers sheltered under the over-arching petal-like stigmas (or rather branches of the style, bearing the true stigma in the form of a thin lip or plate under the apex); most of the style connate with the sepals and petals into a tube. Capsule 3-6-angled, coriaceous. Seeds depressed-flattened, usually in 2 rows in each cell.— Perennials, with sword-shaped or grassy leaves, and large showy flowers; ours with creeping and more or less tuberous rootstocks. (Iris, the rainbow.)

Stems leafy and rather tall, from usually thickened rootstocks, often branching; tube much shorter than the sepals, which are usually much larger than the petals.

Sepals neither bearded nor crested.

Spathes all terminal or at the tips of elongate peduncles.

Flowers brown or yellow.

I. pseudacorus L., the Yellow Iris of European marshes, with several very long linear leaves, bright yellow beardless flowers, and erect petals, is becoming established in N. E., N. Y., and N. J.