1. Frond of the Licorice Fern (Polyopodium vulgare, var. columbianum) illustrating the sessile, obtuse pinnae with crenate margins and arrangement of sori upon underside (x1). 2. Pinnae of P. vulgare, var. columbianum (x3). 3. Pinnae of Polypodium vulgare illustrating characteristic acute, serrulate lobes (x1-1/2).

LICORICE FERN.
(Polypodium vulgare L.)

One of the most common and readily distinguished ferns native to Mt. Rainier National Park. Its most characteristic habitat is moist, mossy locations on cliffs, trunks of trees, down logs, etc. Occasionally, though, one finds it growing in drier sites. Botanically its range is along the Pacific Coast from Alaska to California and eastward to South Dakota, New Mexico and Arizona. Locally it occurs from the lower park boundaries to the Hudsonian Zone, though it is generally found in the park in shady, moist locations below 3500'. Frye states that this fern, while its fronds remain greed all winter, cannot be considered as evergreen, because in the lower elevations this plant's fronds often wither during dry period in mid-summer, putting forth new fronds with the advent of the fall wet periods. These fronds carry over untill the next July. In Mt. Rainier National Park, however, plants have been observed that might be considered truly evergreen, this being a locality with climatic conditions more suitable to the development of an evergreen character in this case.

The fronds vary in size from 6 to 18 inches in length and 1 to 3 inches in width. In general outline they taper from the widest point near, or at, the lower pair of pinnae to a narrow tip. Fronds are simply pinnate; leaf stalk short. The pinnae are sessile, lanceolate, attenuate or acute and usually serrulate. There are from 10 to 35 pairs of pinnae to each frond. Veins are free. Spores are borne in sori that are round, large and conspicuous, nearer the mid-vein than the edge of the pinna and upon the underside. The rhizome has a creeping habit and a distinct licorice taste - hence the common name.

SYNONYMS: P. vulgare, var. occidentale Hook.; P. falcatum Kellog; P. Glycyrrhiza D.C. Eaton; P. vulgare, var. commune Milde; P. occidentale (Hook) Maxon.

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OBTUSE LICORICE FERN.
(Polypodium vulgare L., var. columbianum Gilb.)

This plant, a variety of P. vulgare, has fronds 2 to 8 inches long with 7 to 15 pairs of pinnae. It differs from the above in the size of the fronds and the appearance of the pinnae which are oblong, obtuse, entire or crenate (wavy).

SYNONYMS: P. hesperium Maxon.

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