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Plagiomnium carolinianum (Anderson) T. Kop.
Mountain Wavy-leaf Moss
Federal Protection: No US federal protection
State Protection: No Georgia state protection
Global Rank: G3
State Rank: S2?
Element Locations Tracked in Biotics: Yes
SWAP 2015 Species of Greatest Conservation Need (SGCN): Yes
SWAP 2025 Species of Greatest Conservation Need (SGCN): Yes
2025 SGCN Priority Tier: High Conservation Concern
Element Occurrences (EOs) in Georgia: 4
Habitat Summary for element in Georgia: Moist cliff faces
A moderately robust moss, sterile shoots horizontal, 4-8 (20) cm long with leaves appearing two-ranked. Leaves tongue-shaped, wavy, with a distinctly emarginate, minutely mucronate apex. Leaf margins toothed throughout, teeth small, blunt, mostly1-celled, occasionally lacking. Upon drying, leaves become strongly crisped and contorted as in other species of Plagiomnium. Fertile shoots erect, leaves spirally arranged, male and female gametangia occurring in the same shoot tip, i.e. synoicous. One to four sporophytes emerge from the apex of a fertile shoot. Seta up to 4 cm long. Capsules pendulous, operculum with a long beak.
Among regional species, Plagiomnium carolinianum is likely to be confused only with Plagiomnium rostratum (=Mnium longirostre) from which P. carolinianum differs in having bulging cells of the capsule epidermis (when moist), more deeply emarginated leaf apices, and wavy leaf lamina when moist. The shape of the leaves of P. rostratum are described as elliptic and those of P. carolinianum as oblong-lingulate. Leaf shape is variable and it should be noted that there is some overlap in the leaf shape between these two species especially in robust material of P. rostratum with leaves more oblong-lingulate than elliptic.
Plagiomnium rhynchophorum is a widespread tropical species (Africa, southeast Asia, northern South America, Mexico, Greater Antilles) very similar to Plagiomnium carolinianum and in fact P. carolinianum has been considered to be a mere variety of it (Koponen 1981). However, the most recent checklist of North American Mosses (Anderson et al. 1990) maintains P. carolinianum as a distinct species.
This perennial species of moss is restricted to permanently wet, shaded habitats mostly below 3000 ft in elevation in association with Tsuga canadensis-mixed hardwood forests. Plagiomnium carolinianum is typically found on wet rock but will also grow on soil over rock and humus. The species is restricted to “seepage zones in narrow rock fissures, undercut cliffs, small rivulets hidden away under dense vegetational cover and other such protected habitats” (Anderson 1954, p. 182). It is often found on wet rock in protected pockets associated with waterfalls. These habitats are protected from the scouring of flash floods that affects bryophyte communities along larger streams. Sporophytes develop over late summer through winter and release spores in April and May.
Anderson (1954) listed the liverworts Jubula pennsylvanica and Dumortiera hirsuta and the mosses Eurhynchium riparioides and Thamnobryum alleghaniense as “the most frequent bryophytic associates.” Additional bryophyte associates listed by Anderson (1954): MOSSES: Cirriphyllum piliferum, Ctenidium molluscum, Hookeria acutifolia, Thuidium delicatulum, Entodon sullivantii, Campylium chrysophyllum, Bryocrumia andersonii, Mnium punctatum, M. hornum, Leucobryum glaucum, Fissidens cristatus, F. taxifolius, Plagiothecium muellerianum, Aulacomnium heterostichum; LIVERWORTS, Radula sullivantii, Dumortiera hirsuta subsp. nepalensis, Pallavicinia lyellii, Riccardia multifida, Plagiochila porelloides, Metzgeria leptonerura, and Scapania nemorea.
Steep-sided stream ravines along the Chattooga River and stream ravines elsewhere in northern Georgia below 3000 ft elevation.
Endemic to southeastern North America. Narrowly distributed in the southern Blue Ridge: Georgia (Rabun and Stephens Cos.), North Carolina (Haywood, Jackson, Macon, Swain, and Transylvania Cos.), South Carolina (Oconee and Pickens Cos.), Tennessee (Blount and Sevier Cos.), and apparently disjunct to the Jackson County Mountains in the Cumberland Plateau of Alabama (Jackson Co.).
Loss of habitat.
| Threat 1 | Threat 2 | Threat 3 | |
|---|---|---|---|
| General Threat | Natural system modifications | None | None |
| Specific Threat | Dams & water management/use | None | None |
Plagiomnium carolinianum is documented from four Georgia locations.
Protection of habitat especially from activities that would remove the shading vegetation.
Anderson, L.E. 1954. A new species of Mnium from the Southern Appalachians. The Bryologist 57: 177—188.
Anderson, L.E., H. A. Crum, and W. R. Buck. 1990. List of the Mosses of North America North of Mexico. The Bryologist 93: 448-499.
Koponen, T. 1981. A synopsis of Mniaceae (Bryophyta). V. Taxa in Africa south of the Sahara. Ann. Bot. Fenn. 18: 105–111.
Crum, H. & L. E. Anderson. 1981. Mosses of Eastern North America. Columbia University Press, New York, 2 vols.
Zartman, C. E., and J. D. Pittillo. 1998. Spray cliff communities of the Chattooga Basin. Castanea 63: 217-240.
Paul G. Davison
September 2010