Fig. 204. Pyrola rotundifolia. The herb of Pyrola rotundifolia, Linné.
Nat. Ord.—Ericaceae.
COMMON NAMES: Canker lettuce, Shin-leaf, False wintergreen, Pear-leaf wintergreen.

Botanical Source.—This is a perennial, low, scarcely suffruticose evergreen herb. The leaves are radical, or nearly so, orbicular-ovate, nearly 2 inches in diameter, smooth, shining, thick, entire, or crenulate, usually shorter than the petiole, with conspicuous, reticulate veins. The petioles are margined, and as long as, and usually much longer than the leaf. The scape is mostly racemose, 3-angled, 6 to 12 inches high, with scaly bracts at the base and in the middle. The flowers are many, large, fragrant, white, drooping, about ¾ inch broad, and borne in an oblong, terminal raceme. Calyx 5-parted, persistent; lobes lanceolate, acute, with somewhat spreading tips, ½ or ⅓ the length of the petals. Petals 5, roundish-obovate, nearly spreading, concave, deciduous. Stamens 10, ascending; filaments awl-shaped, naked; anthers large, pendulous; stigmas exserted beyond the ring; style declining and curved, and longer than the petals. The capsule is 5-celled, 5-valved, opening at the angles, and many-seeded (W.—G.).

Photo: Pyrola media 3. History and Chemical Composition.—This plant is common in damp and shady woods throughout various parts of the United States, bearing numerous white flowers in June and July. The whole plant is used, and imparts its medicinal properties to water. P. elliptica, Nuttall; P. secunda, Linné; and P. chlorantha, Swartz, possess like properties. Mr. E. N. Smith (Amer. Jour. Pharm., 1881, p. 549) found the leaves of P. elliptica, P. chlorantha, and P. rotundifolia var. asarifolia, Michaux, to contain arbutin, ericolin, urson, tannic, gallic, and malic acids, gum, sugar, albumen, little volatile oil, and some coloring matter.

Action, Medical Uses, and Dosage.—Round-leaved pyrola is tonic, astringent, diuretic, and antispasmodic. Used in decoction, both internally and externally, in various cutaneous eruptions, likewise in a carcinomatous or scrofulous taint of the system, and in leucorrhoea, and some uterine diseases. As a local application, it will be found of service in sore throat, and ulcerations of the mouth, indolent ulcers, ophthalmia, etc., and forms an excellent soothing poultice for boils, carbuncles, and all painful tumors or swellings. The decoction, taken internally, is valuable in many urinary affections, relieving irritation, and is reputed very useful in gravel, hematuria, and ulceration of the bladder, and in some nervous diseases. The decoction and extract have been used with success in convulsions, and once formed a large portion of a popular nostrum for epilepsy. Dose of the decoction, 1 or 2 fluid ounces, 3 or 4 times a day; of the extract, from 2 to 5 grains. A strong tincture of the fresh plant (℥viii to alcohol, 76 per cent, Oj) may be given in doses of from 1 to 30 drops.

Specific Indications and Uses.—To relieve irritation of the urinary tract.

King's American Dispensatory, 1898, was written by Harvey Wickes Felter, M.D., and John Uri Lloyd, Phr. M., Ph. D.