The Common Water Dropwort.
1. The Common Water Dropwort (Œ. fistulosa).—An erect plant, from two to three feet high, with a fleshy, fibrous root; creeping runners; and a thick, hollow, slightly-branched stem. Its radical leaves are bipinnate, with segments cut into three or five narrow lobes; and the stem leaves have long, hollow stalks, with a few narrow segments at the top. The umbels have from three to five rays, usually with no primary bracts, and a few, narrow secondary ones.
2. The Hemlock Water Dropwort (Œ. crocata) is a larger plant, from two to five feet high, with a tuberous root and a thick, branched stem. Its leaves are bipinnate, with stalked, shining leaflets that are irregularly cut. The umbels are on long stalks, and have nearly twenty rays, several narrow secondary bracts, and sometimes a few primary ones. The middle flowers of each secondary umbel are perfect and almost sessile, but the outer ones are stalked and staminate.
3. The Fine-leaved Water Dropwort (Œ. Phellandrium) grows from one to four feet high, and has an erect, creeping or floating stem with runners at the base. The upper leaves are bipinnate, with small, cut segments; and the submerged ones are deeply cut into very narrow, almost hair-like lobes. The umbels are small, on short stalks in the angles of the branches or opposite the leaves. They have about ten rays, narrow secondary bracts, but no primary ones.
The Marsh Thistle.
All three of the above species flower from July to September.
Next follow a few composite flowers (order Compositæ), the first of which is the Marsh Thistle (Carduus palustris) that varies from two to eight feet in height, and bears dense clusters of purple (occasionally white) heads during July and August. Its stem is stiff, hollow, slightly branched, and thickly covered with very prickly wings that are continuous with the margins of leaves above them. The leaves are narrow, wavy, deeply divided into prickly lobes, with scattered hairs on both surfaces; the lower ones often seven or eight inches long; and the upper much smaller and narrower. The flower-heads are ovoid, surrounded by an involucre of many closely-overlapping bracts with prickly tips.
The two Bur Marigolds (Bidens) are more or less common in marshes and other wet places. They are both smooth plants with opposite leaves, and hemispherical heads of yellowish flowers surrounded by two or three rows of bracts, the outer of which are spreading. The receptacle is flat, with membranous scales between the florets; and the fruits are crowned by from two to five stiff, prickly bristles. The more abundant of these is the Nodding Bur Marigold (B. cernua), a stout plant, from one to two feet high, distinguished by its narrow, entire, sessile leaves, and its drooping flower-heads. The other—the Trifid Bur Marigold (B. tripartita)—has three-cleft, stalked leaves, and heads erect or only slightly drooping.
