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DITRICHUM FAMILY (DITRICHACEAE)

This family consists of individuals which are very similar in appearance to Dicranum and have affinites with this group. There are two of the seven North American genera considered in this study, namely Ceratodon and Ditrichum.

Ceratodon purpureus (Hedw.) Brid., the Purple Horn-cap Moss, is probably the most widely distributed of all Mt. Rainier mosses. It usually grows on soil in rock crevices, but will occupy any open area. The drawing (Plate XI, Fig. 1) shows the characteristics of the moss, but the best marks of identification probably are the deep furrows and dark red-brown color of the capsules, incorrectly called purple - whence the common name. Anyone who has not seen the peristome of this moss under a lens has missed one of the most beautiful sights in nature. It is found throughout various elevations of the park, as near Longmire at 2750 foot where the specimens are about three times the size of those collected at 6800 feet on the Skyline Trail.

The genus Ditrichum is represented by four species in the park. It differs from Ceratodon largely in the nature of the capsule, those of Ditrichum not being furrowed as a rule, and usually standing erect, while Ceratodon capsules are furrowed and sometimes strumose.

Key to the Species

Ditrichum Schimperi (Lisq.) Paris, as indicated by the key, is distinguished by the bright yellow seta and capsules which usually are erect. They were collected at Ohanapecosh, 2000 feet. D. ambiguum was collected among heather in firm, clayey soil on the slopes of Eagle Peak. The plants grow closely together and are bright green in color. D. heteromallum is somewhat smaller, and is distinguished from the foregoing by the incurved leaf margins. A specimen was collected near Longmire. D. flexicaule var. densum was collected at the summit of Eagle Peak, 5935 feet, grows in dense sods and is yellowish-green in color.

GRIMMIA FAMILY (GRIMMIACEAE)

A large family of mosses with many representatives on Mt. Rainier. They are usually dark-green in color, and are found almost entirely on rocks. The peristome of 16 teeth serves to distinguish then for the beginner from the Andreaeas, which have a capsule opening by four valves. Two sub-families occur in the park - the Grimmieae and the Scoulerieae. When fruiting, the former can always be distinguished by the fact that the capsules are terminal, while in the latter sub-family they are lateral in position.

Sub-family (Grimmieae)

This sub-family includes, in this study, two genera and seventeen species and varieties. The two genera, Grimmia and Racomitrium, both have costate leaves which are not crisped; the capsules are either immersed or exserted. The two genera differ in the exserted capsules and basal linear leaf cells with sinuose walls and deeply cleft peristome of Rhacomitrium, Grimmia's having immersed or emergent capsules and shorter basal leaf cells.

KEY TO SPECIES OF GRIMMIA

Grimmia apocarpa var. gracilis (Schleich) (Web. & Mohr.), is a slender dark-green form, growing in spreading mats on cliffs along the west side roads. G. calyptrata Hook forms loose, rounded tufts on rocks that have a silvey-grey appearance due to the long hair points of the leaves. Collected on steep cliffs near saddle of Eagle Peak. G. trichophylla Grey. grows in loose yellowish-green tufts, black at base with leaves slightly twisted upon drying. This appears to be a fairly common Grimmia, having been found below Gobler's Knob Lookout, on Indian Henry's Hunting Ground trail and near Longmire. G. Doniana Sm. is found at higher altitudes on the rocks of the great cleavers of Mt. Rainier. Here it grows in small, low, round, cushion-like formations which are whitish at the top and gray-green beneath. Type locality - Skyline Trail 6800 feet.

G. Alpestris Nees, is another high alpine species very similar to the foregoing, from which it differs largely in its leaf cells which are mere nearly round. It is widely distributed at high altitudes, being collected on the Skyline Trail, Eagle Peak Summit, near Van Trump Glacier, and above Yakima Park. Specimens collected did not appear as dark-green as G. commutata Hueben. forms broad, loose, dark-green tufts similar to G. trichophylla, from which it differs by its straight sets and curved capsules. Collected above Yakima Park.

KEY TO SPECIES AND VARIETIES OF RHACOMITRIUM

Rhacomitrium canescens (Timm) Brid. is a common form covering rocks in dense, tufts about Longmire and the Longmire Camp Grounds. R. canescens f. ericoides (Brid.) Moenk differs from the above in that it has many short, tuft-like, lateral branchlets. It is also found below Longmire Camp Grounds. R. canescens f. epilosum (Milde) has muticous leaves. This form was found just below Van Trump Park on Van Trump Creek. Rhacomitrium heterostichum (Hedw.) (See Plate XI, Fig. 3), grows in close, round tufts of a gray-green color. While quite common in western U. S., it is apparently rare east of the Mississippi River. It was collected from various localities, among which are the top of Ramparts Ridge, above Comet Falls, summit of Eagle Peak, and near Longmire. Three varieties were collected; var. gracilescens (Bry Eur.), which has muticous leaves, was found above Lake Louise and on the Klapatche Trail; var. sudeticum Funck, which differs from R. heterostichum in the absence of lateral branchlets, was found in a number of localities, among which are Indian Henry's Hunting Ground Trail, Klapatche, Van Trump and Eagle Peak; var. ramulosum Lindb. has many short, lateral branchlets and elongated upper leaf cells. It was found at Longmire and below the Carbon Glacier.

Rhacomitrium patens Hedw. was collected above Lake Louise and on the Skyline Trail, and forms loose, dark-green tufts on rocks.

Rhacomitrium lanuginosum Hedw. is very hoary in appearance, with short, lateral branchlets. Found above Yakima Park at 6800 feet.

Rhacomitrium aciculare Brid. is fairly common, and occurs in coarse, dull dark-green tufts.

SUB-FAMILY SCOULERIEAE

A small group represented here by a single genus - Scouleria. Plants are water-loving (hydrophytic) and the capsule is immersed. It was named after Dr. John Scouler.

Scouleria aquatica Hook. was found in only one locality - the rocks in and near the water of the Ohanapecosh River near Ohanapecosh Hot Springs. The plants are large and blackish in color. A characteristic easily noted the beginner is the elongated columella, which is persistently attached to the flat lid. (See Plate XI, Fig. 4).

PLATE XI.

Fig. 1. (Ditrichaceae). Ceratodon purpureus Hedw. 1a - entire plant x3. 1b - calyptra. 1c - single leaf, magnified.
Fig. 2. (Tortulaceae). Desmatodon latifolius B. & S. 2a - entire plant x5. 2b - calyptra, side view. 2c - single leaf, magnified.
Fig. 3. (Grimmiaceae, subfamily Grimmieae). Rhacomitrium heterostichum Hedw. 3a - entire plant, moist x2. 3b - leaf, magnified.
Fig. 4. (Grimmiaceae, subfamily Scoulerieae). Scouleria aquatica Hook. 4a - branch, moist, showing lid of capsule attached to the columella. 4b - leaf, magnified.

Descriptions continued...