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HYPNUM FAMILY - (HYPNACEAE)

This large family consists of mosses that are creeping in habit, and in the lower zones of the park, where they are most abundant, they form beautiful mats covering fallen trees, trunks of standing trees, and carpeting the ground. The distinguishing characteristics of the family are capsules borne on short lateral branches (pleurocarpous condition), and smooth leaves and elongated leaf cells. The family is divided into eight subfamilies of which six are represented in this study.

KEY TO THE SUBFAMILIES

Subfamily (Amblystegieae)

Mosses of this group will vary greatly in character as they are of wide range on the mountains. A great number of the species are moisture-loving and will be found in wet meadows or on rocks kept moist by running water. The two genera discussed in this study - Drepanocladus and Hygrohypnum - are distinguished by differences in their costa, the former genus having a costa which is single and runs to the middle of the leaf, while the latter has a costa that is percurrent or excurrent.

The genus Drepanocladus is composed of a group of mosses commonly growing in water and undergo considerable variation because of the water habitat. Because of the manner in which the branches turn back at the tip, this genus received its name, which means "sickle branch." Drepanocladus uncinatus (Hedw.) Warnst (See Plate XV, Fig. 2), grows in wet places on Mt. Rainier but does not grow submerged. The leaves have ear-like projections (auricles). Specimens were found in wet ground in Van Trump Park. D. uncinatus var. plumulosus (Br. and Sch.) is a more slender and closely pinnate from that grows on moist ground mixed with other mosses. D. exannulatus (Guemb) Warnst. is recognized by stout costae and by large decurrent auricles. Specimens were collected in wet ground above Lake Louise. The genus Hygrohypnum consists of mosses usually found at higher altitudes on the mountain. They frequent wet rocks or beds of streams and form mats mixed with sand and gravel. Hygrohypnum ochraceum (Turn.) Loeske was found growing in boggy situations near Ohanapecosh Hot Springs. The loaves are more or less short and broad, soft in texture and obtuse at the apex. H. molle (Hicks. Schimp.) was found growing on a steep rock slope below snow fields above St. Andrews Park where melting snow kept the rocks moist. The specific name indicates the soft texture of the leaves. H. Bestii (Ren. and Bryhn.) is really a subspecies of H. molle having the leaf of this species and habit and appearance of H. dilatatum.

Subfamily (Brachythecieae)

A family with many representatives of wide distribution of the mountain. They have many resemblances to Hypneae but possess a distinctive glossy appearance. The leaves are usually singly costate halfway or more.

KEY TO THE GENERA

Homalothecium nevadense (Lesq.) H. & C. The only species of this genus found in the park is closely allied with Camptothecium, having the same bright, glossy yellow-green appearance. It appears at Ohanapecosh and elsewhere at lower elevations, creeping in thin, spreading mats over rocks. The genus Camptothecium, represented in this study by three species, is similar to the foregoing genus in many respects, the essential differences being the curved capsule and cilia in the peristome. Camptothecium megaptilum Sull. is a beautiful, shiny, yellow-green form that is found abundantly on the ground above Longmire and on the lower Eagle Peak Trail. In habit it resembles Hylocomium a great deal. C. lutescens (Hedw.) is a much less robust form than the foregoing, and resembles more Brachythecia in habit. It occurs on lower portion of tree trunks and stumps; rotting logs are often heavily covered by it in places around the Trail of the Shadows and on the lower Longmire-Paradise Trail. C. pinnatifidum Sull. and Lesq.) is a beautiful, regularly pinnate form with slender, incurved branches. It is found on tree trunks at Ohanapecosh. The genus Eurhynchium consists of plants growing in loose, soft mats. The stems are pinnately branched and usually creeping. Eurhynchium praelongum (Dill., L.) is a fairly common moss at elevations of 2000 to 2800 feet. It is abundant around Longmire and between there and the entrance, usually growing on the ground mixed with other mosses. The stems are slender, graceful in appearance, bright or dull green in color. E. oreganum Sulliv. can be distinguished from the former species by its yellow-green, almost brownish, color. It occurs on the ground, on decayed logs and bases of trees. The easiest place to find quantities of this beautiful moss is along the road between the bridge and the Longmire Community House. It is also found at Ohanapecosh. Pseudisthecium stoloniferum Hook. is the only Pseudisothecium thus far discovered. The species differs from the eastern species, P. myosuroides, by its very long, tapering (flagelliform) branches. The primary stems are creeping, and long, tapering branches make a most beautiful covering for the tree trunks and for rocks in moist places. This moss is one of the most frequently encountered mosses of the lower elevations up to about 3500 feet. It was collected in many localities, including Ramparts Ridge Trail at 3500 feet, Eagle Peak Trail at the same elevation, at Ohanapecosh and on the road to Carbon Glacier.

The genus Brachythecium is one of wide occurrence in the park. The mosses of this genus are of medium to small size. The capsules are short-ovoid to oblong-ovoid, and nodding to bow-shaped (cernuous-arcuate), contracted under the mouth when dry. Of the five groups into which the genus is divided, three are represented here. The Rutabulum group, characterized by rough seta, well-developed annulus and ovate-deltoid stem leaves, includes B. rutabulum. The Reflexum group, characterized by non-plicate, triangular-ovate, decurrent leaves, includes B. Starkei and B. Bestii. The Velutinum group, characterized by small size and somewhat secund leaves, includes most of our Mt. Rainier species, namely, B. velutinum, B. thedinii, B. Leibergii and B. collinum.

PLATE XV.

Fig. 1. (Hypnaceae, subfamily Brachythecieae). Brachythecium Starkei Br. &. Sch. 1a - entire plant showing two mature and one young sporophyte. 1b - leaf, magnified.
Fig. 2. (Hypnaceae, subfamily Amblystegieae). Drepanocladus uncinatus Hedw. Warnst. 2a - portion of plant x3. 2b - single leaf x20.
Fig. 3. (Hypnaceae, subfamily Hylocomieae). Rhytidiopsis robusta Hook. 3a - portion of plant x2. 3b - single leaf x10.

Descriptions continued...