Jack-in-the-pulpit

Jack-in-the-pulpit is a 12″ to 36″ tall, erect, perennial forb that rises from a corm with secondary roots.

There is no central stem.

Usually 2 leaves, sometimes just 1, rarely 3 rise from the corm on long, erect stalks that reach 24″ by the time the plant is in full flower. The leaves are divided into 3, rarely 5, more or less stalkless leaflets. The leaflets are 2½″ to 8″ long, 1¼″ to 5½″ wide, and taper gradually to a point at the tip with concave sides along the tip. There is a prominent midvein originating from the base of the leaf and extending to the tip, and up to 10 or more prominent, parallel, lateral veins branching pinnately off the midvein. The lateral veins curve abruptly toward the leaf tip before reaching the margin, and join together in a marginal vein. The angle formed between the midvein of the terminal leaflet and either lateral leaflet is 90° or less.

The upper surface is medium to dark green and hairless. The lower surface is paler green, hairless, and covered with a whitish, waxy coating (glaucous). The margins are untoothed. The terminal leaflet is egg-shaped or broadly diamond-shaped. The lateral leaflets are distinctly asymmetrical and smaller than the terminal leaflet.

A single flower stalk (peduncle) rises from the corm with the leaves. The peduncle is shorter than the leaf stalks.

The inflorescence is a spike with tiny flowers crowded on a thickened axis (spadix). The spadix is yellow, 1″ to 3½″ tall, blunt-tipped, and club-shaped, tapering slightly from a narrower base to a broader tip. A leaf-like bract (spathe) forms a tube surrounding the spadix. It is expanded near the tip forming a long, tapering hood that covers the spadix and tube. The hood opens at maturity, exposing half of the spadix. The spathe is green, often with purple stripes.

The male flowers are located above the female flowers on the lower half of the spadix. The upper part of the spadix has no flowers.

The fruit is a nearly spherical, 1 ⁄5″ to ¼″ long, red berry with 1 to 3 seeds, borne in a tight cluster up to 2″ long.

12″ to 36″

Yellow

Trilliums (Trillium spp.) look similar when no flower or fruit is present. They can be distinguished from Jack-in-the-pulpit by the veins on the leaves. Trillium leaves have 5 prominent veins originating from the base of the leaf and extending to the tip. The lateral veins form a network. The angle formed between the midvein of the terminal leaflet and either lateral leaflet is greater than 90° (obtuse).

Moist to moderate moisture. Woods. Partial sun to shade.

April to June

Jack-in-the-Pulpit Rust forms many yellowish orange pustules on the leaves and spathe, and it also attacs the corm. It causes reduced plant growth and it inhibits polination and vegetative propagation. Most infected female plants are unable to produce seeds.

Sources

2, 3, 4, 5, 7, 24, 28, 29, 30.

Native

Common

Some taxonomic authorities recognize three, four, or five of the subspecies of Jack-in-the-pulpit listed below. GRIN and NatureServe each recognize 3 subspecies, USDA PLANTS recognizes 4 subspecies. Some sources treat them as varieties. Several sources, including Plants of the World Online, World Flora Online, Catalog of Life, and iNaturalist, treat them as separate species. iNaturalist treats the five species as the Arisaema triphyllum Species Complex. A few sources, including ITIS, GBIF, and Flora of North America (FNA), treat Arisaema triphyllum as one highly variable species with no subspecies.

Whether species, subspecies, varieties, or morphological forms, they are reproductively isolated in the wild. They can be recognized in the field but herbarium specimens are difficult to separate. There is much overlap in the defining characteristics, with many intermediate forms and hybrids. FNA does not recognize any subspecies but does include a key for distingushing between three of them.

Plant

Plant

Flower

Flower

Leaf

Leaf

Leaves

Infructescence

Infructescence

Jack In The Pulpit
DianesDigitals

Arisaema triphyllum
Butler Herbarium

Jack-in-the-pulpit (Arisaema triphyllum var.)
Andree Reno Sanborn

Arisaema atrorubens (Jack-in-the-Pulpit)
Allen Chartier

Jack in the Pulpit (Arisaema triphyllum)
colong7034

MyNature Apps; Identifying Jack-in-the-Pulpit, Arisaema triphyllum
MyNatureApps

Jack in the Pulpit (Arisaema triphyllum)
wvoutdoorman

Location: Hugo, MN

This one was big !

Location: Nerstrand Big Woods State Park

Crystal Boyd
6/2/2013

Location: Pine Bend Bluffs SNA