CUPPLANT INDIANCUP RAGGED CUP ROSINPLANT

(Silphium perfoliatum) Thistle family



Plower-heads - Yellow, nearly flat; 2 to 3 in. across; 20 to 30

narrow, pistillate ray florets, about 1 in. long, overlapping in

2 or 3 series around the perfect but sterile disk florets. Stem:

4 to 8 ft. tall, square, smooth, usually branched above.

Leaves: Opposite, ovate, upper ones united by their bases to form

a cup; lower ones large, coarsely toothed, and narrowed into

margined petioles; all filled with resinous juice.

Preferred Habitat - Moist soil, low ground near streams.

Flowering Season - July-September.

Distribution - Ontario, New York, and Georgia, westward to

Minnesota, Nebraska, and Louisiana.



It behooves a species related to the wonderful compass-plant

(q.v.) to do something unusual with its leaves; hence this one

makes cups to catch rain by uniting its upper pairs. Darwin's

experiments with infinitesimal doses of ammonia in stimulating

leaf activity may throw some light on this singular arrangement.

So many plants provide traps to catch rain, although fourteen

gallons of it contain only one grain of ammonia, that we must

believe there is a wise physiological reason for calling upon the

leaves to assist the roots in absorbing it, A native of Western

prairies, the cup-plant has now become naturalized so far east as

the neighborhood 6f New York City.