One of our oddest-looking spring flowers, a relative of the tropical Anthurium and the Calla so popular with funeral directors. Jack-in-the-pulpit blooms in open woodlands in May; this one grew on a wooded hillside in Mount Lebanon. The spathe (the leafy enclosure that forms the “pulpit”) is quite variable, with some plants showing deep maroon stripes and others almost no stripes at all.

Gray describes the genus and the species:

ARISAEMA Martius. INDIAN TURNIP. DRAGON ARUM
Spathe convolute below and mostly arched above. Flowers monoecious or by abortion dioecious. Sterile flowers above the fertile, each of a cluster of almost sessile 2-4-celled anthers, opening by pores or chinks at the top. Fertile flowers a 1-celled ovary containing 5 or 6 erect orthotropous ovules; in fruit a l-few-seeded scarlet berry. Low perennial herbs, with a tuberous rootstock or corm, sending up a simple scape sheathed with the petioles of the simple or compound veiny leaves. (Name from aris, a kind of arum, and aima, blood, from the spotted leaves of some species.)

A. triphyllum (L.) Schott. (INDIAN TURNIP, JACK-IN-THE-PULPIT.) Leaves mostly 2, divided into 3 elliptical-ovate pointed leaflets; spadix mostly dioecious, subcylindric or club-shaped, obtuse, much shorter than the spathe, which is smooth or corrugated in its tubular part and incurved-hooded at its flat ovate-lanceolate pointed summit. (A. pusillum Nash; A . Stewardsonii Britton.) Rich woods. May. Corm turnip-shaped, wrinkled, farinaceous, with an intensely acrid juice; spathe with the petioles and sheaths pale green, or often dark purple or variegated with dark purple and whitish stripes or spots.

In her Wild Flowers: An Aid to Knowledge of Our Wild Flowers and Their Insect Visitors, Neltje Blanchan has an expansive (and sometimes cloyingly whimsical) article about the Jack-in-the-Pulpit:

JACK-IN-THE-PULPIT; INDIAN TURNIP
(Arisaema triphyllum) Arum family

Flowers – Minute, greenish yellow, clustered on the lower part of a smooth, club-shaped, slender spadix within a green and maroon or whitish-striped spathe that curves in a broad-pointed flap above it. Leaves: 3-foliate, usually overtopping the spathe, their slender petioles 9 to 30 in. high, or as tall as the scape that rises from an acrid corm. Fruit: Smooth, shining red berries clustered on the thickened club. Preferred Habitat – Moist woodland and thickets. Flowering Season – April-June. Distribution – Nova Scotia westward to Minnesota, and southward to the Gulf States.

A jolly looking preacher is Jack, standing erect in his particolored pulpit with a sounding-board over his head; but he is a gay deceiver, a wolf in sheep’s clothing,, literally a “brother to dragons,” an arrant upstart, an ingrate, a murderer of innocent benefactors! “Female botanizing classes pounce upon it as they would upon a pious young clergyman,” complains Mr. Ellwanger. A poor relation of the stately calla lily one knows Jack to be at a glance, her lovely white robe corresponding to his striped pulpit, her bright yellow spadix to his sleek reverence. In the damp woodlands where his pulpit is erected beneath leafy cathedral arches, minute flies or gnats, recently emerged from maggots in mushrooms, toadstools, or decaying logs, form the main part of his congregation.

Now, to drop the clerical simile, let us peep within the sheathing spathe, or, better still, strip it off altogether. Dr. Torrey states that the dark-striped spathes are the fertile plants, those with green and whitish lines, sterile. Within are smooth, glossy columns, and near the base of each we shall find the true flowers, minute affairs, some staminate; others, on distinct plants, pistillate, the berry bearers; or rarely both male and female florets seated on the same club, as if Jack’s elaborate plan to prevent self-fertilization were not yet complete. Plants may be detected in process of evolution toward their ideals: just as nations and men are. Doubtless, when Jack’s mechanism is perfected, his guilt will disappear. A little way above the florets the club enlarges abruptly, forming a projecting ledge that effectually closes the avenue of escape for many a guileless victim. A fungus gnat, enticed perhaps by the striped house of refuge from cold spring winds, and with a prospect of food below, enters and slides down the inside walls or the slippery colored column: in either case descent is very easy; it is the return that is made so difficult, if not impossible, for the tiny visitors. Squeezing past the projecting ledge, the gnat finds himself in a roomy apartment whose floor – the bottom of the pulpit – is dusted over with fine pollen; that is, if he is among staminate flowers already mature. To get some of that pollen, with which the gnat presently covers himself, transferred to the minute pistillate florets waiting for it in a distant chamber is, of course, Jack’s whole aim in enticing visitors within his polished walls; but what means are provided for their escape? Their efforts to crawl upward over the slippery surface only land them weak and discouraged where they started. The projecting ledge overhead prevents them from using their wings; the passage between the ledge and the spathe is far too narrow to permit flight. Now, if a gnat be persevering, he will presently discover a gap in the flap where the spathe folds together in front, and through this tiny opening he makes his escape, only to enter another pulpit, like the trusted, but too trusting, messenger he is, and leave some of the vitalizing pollen on the fertile florets awaiting his coming.

But suppose the fly, small as he is, is too large to work his way out through the flap, or too bewildered or stupid to find the opening, or too exhausted after his futile efforts to get out through the overhead route to persevere, or too weak with hunger in case of long detention in a pistillate trap where no pollen is, what then? Open a dozen of Jack’s pulpits, and in several, at least, dead victims will be found – pathetic little corpses sacrificed to the imperfection of his executive system. Had the flies entered mature spathes, whose walls had spread outward and away from the polished column, flight through the overhead route might have been possible. However glad we may be to make every due allowance for this sacrifice of the higher life to the lower, as only a temporary imperfection of mechanism incidental to the plant’s higher development, Jacks present cruelty shocks us no less. Or, it may be, he will become insectivorous like the pitcher plant in time. He comes from a rascally family, anyhow. (See cuckoo pint.)

In June and July the thick-set club, studded over with bright berries, becomes conspicuous, to attract hungry woodland rovers in the hope that the seeds will be dropped far from the parent plant. The Indians used to boil the berries for food. The farinaceous root (corm) they likewise boiled or dried to extract the stinging, blistering juice, leaving an edible little “turnip,” however insipid and starchy.