This section is from the book "British Wild Flowers - In Their Natural Haunts Vol5-6", by A. R. Horwood. Also available from Amazon: A British Wild Flowers In Their Natural Haunts.
Floating leaves divided half-way into 3 wedge-shaped segments. Submerged leaves thread-like, generally stiff. Flowers large. May-September. Herbaceous perennial.
Orange Lr.lsam (Impatiens biflora, Walt. = /. fulva, Nutt.). - Differs from I. Noli-?ne-tangere, L., as follows: - Leaves acute. Flowers orange. Posterior sepal suddenly contracted into a turned-back, notched spur. 1-3 ft. July-October. Herbaceous annual. American1, naturalized.
Floating. Segments of submerged leaves parallel. Fruit as long as styles. fin CE. Pliellandrhtm, Lamk., a plant of still waters, leaf-segments are spreading and fruit twice as long as styles.) July-September. Herbaceous perennial.
Ascending. Glandular, hairy, musk-scented. Leaves elliptical, small. Flowers narrow, yellow. 6-18 in. July. Herbaceous perennial. Naturalized.
Inflorescence long, dense-flowered. Flower-stalks ascending. Flowers generally pale-blue. Fruit ovate-obcordate, narrow below, with narrow notch at lip. 1-2 ft. July. Herbaceous perennial.
Differs from last as follows: - Inflorescence loose. Flower-stalks horizontal. Flowers white or pale-pink. Fruit broad, not narrowed below, deeply notched.
Differs from M. aquatica, L., as follow: - Leaves dull-green and hairy above, densely woolly below. Flowers in a dense, cylindrical spike, interrupted below. Calyx-teeth two-thirds the length of the tube, awl-shaped. August-October. Herbaceous perennial. Probably a hybrid.
Differs from 5. sylvatica, L., as follows: - Stem shorter, hollow. Leaves much narrower, with short (or no) stalks. Hairs less coarse. Odour less disagreeable. Flowers paler. A hybrid with 5. sylvatica, L. (S. ambigua, Sm.) occurs.
Stem rough, with turned-back prickles. Leaves oblong-ovate to arrow-shaped. Flowers white. 6 in.-2 ft. July-October. Herbaceous annual. North American, naturalized in County Kerry.
Floating leaves 4-6 in., leathery, blade gradually merging into the stalk, elliptic-lanceolate, with net-like veins. Submerged leaves long, clear-green. Fruit broadly obovate; keel acute, tuber-cled in acute angles below. June. Herbaceous perennial. River Loddon.