Leptodontium viticulosoides var. sulphureum (Müller Hal.) R.H. Zander
Family: Pottiaceae
Synonyms
Leptodontium excelsum (Sullivant) E. Britton
L. sulphureum var. panamense Lorentz
Syrrhopodon excelsus Sullivant
Trichostomum sulphureum Müller Hal.
Zygodon sullivantii Müller Hal.
Zander (2007) treated Leptodontium excelsum as a synonym of Leptodontium viticulosoides var. sulphureum (Müller Hal.) R.H. Zander thus extending the range of what some consider to be a Southern Appalachian endemic to Mexico, Central America, and South America. Crum and Anderson (1981, p. 317) , in discussing the various synonymies, considered Southern Appalachian Leptodontium excelsum "genetically distinct from variables of a far disjunct area."
NatureServe Conservation Status
G2
The NatureServe Conservation Status applies to Leptodontium excelsum, presumably as a narrow endemic restricted to the Southern Appalachians.
Distribution
North America. U.S.A. (Georgia, North Carolina, Tennessee, Virginia). Mexico. Central America. South America. (Zander 2007). The Georgia location is unknown, listed as "Mountains" on the specimen label, the specimen collected in 1850 by C. L. Lesquereux (NY) (Zander 1972).
Habitat
Restricted to red spruce-Fraser fir forests above 5500 ft. elevation, occurring predominantly on trunks and limbs of Fraser fir, also found on trunks of mountain ash. Rarely found on other substrates, e.g. spruce trees (Britton 1908, Davison et al. 1999), rock (Anderson 1951; on rock at Waterrock Knob and Clingmans Dome, observed by P.G. Davison), peaty forest floor (steep, south-facing slope, Mt Buckley, N.C, persistent and slowly spreading on sun-exposed peat, observations from 1999-2018 by P.G. Davison), Prunus pennsylvanica and Viburnum alnifolium (Davison et al. 1999).
Zander (1980, 1996) put forth the hypothesis that L. viticulosoides in the Southern Appalachians was spreading due to human induced environmental change (acid rain and associated insect infestations) that has led to the death of Fraser fir trees thereby producing a greater “availability of suitable, loose bark substrate.” Based on our observations, in the last 20 years L. viticulosoides has greatly increased in abundance and in luxuriance on Clingmans Dome. Its presence on Roan Mountain is far less noticeable with only small tufts seen on 1-3 fir trees from 1999-2018. Historically the species could not be found on Roan Mountain by Lewis Anderson who made a decided effort to find it there (Anderson 1951). To our knowledge, L. viticulosoides has yet to be found in the Fraser fir forests on Mt. Mitchell, N.C. or Mt. Rogers, Virginia.
Rather than prospering on dead firs as observed by Zander (1980), the species is currently (2018) doing very well on living fir trees. We hypothesize that, with greater openings in the canopy due to surrounding tree death, L. viticulosoides is capable of outcompeting other mosses under conditions of higher light intensities provided there are no prolonged periods of desiccation.
Brief Description and Tips for Identification
Shoots slender, flexuose, up to 7 cm long, usually yellow green occurring as isolated strands or forming large, loose tufts, often pendent. Leaves typically widely spreading, rather distant, long-lanceolate, apex narrowly acute, decurrent at base, costa extending to the leaf apex. Leaf margin coarsely serrate in the upper half of the leaf, recurved below. Leaf cells pluripapillose. Occasional leaves with rhizoids growing from leaf apices.
Dioicous or Monoicous? Sporophytes unknown in the Southern Appalachians. According to Crum and Anderson (1981) regional material is autoicous; Zander (2007) stated that only archegoniate plants occur in the Southern Appalachians and suggested Crum and Anderson (1981) mistook galls, known to occur on some specimens, for perigonia (androecia). Leptodontium as described at the generic level by Crum and Anderson (1981) and Zander (2007) produces axillary brood bodies as a specialized means of asexual reproduction; however, this form of asexual reproduction is not mentioned specifically for regional L. viticulosoides. Plants may spread by general fragmentation.
Leptodontium viticulosoides can be reliably identified in the field. It is most likely to be confused with co-occurring Zygodon viridissimus which differs in having more closely spaced leaves with leaf margins entire or rarely with an isolated tooth. Zygodon viridissimus typically forms small cushions consisting of closely spaced shoots with closely spaced leaves as compared to the loose tufts of elongated shoots with distant leaves characteristic of Leptodontium excelsum.
Leptodontium flexifolium, a much rarer species regionally, occurs on moist rock outcrops (Grandfather Mountain, Chestnut Bald, North Carolina), is smaller than L. viticulosoides, and forms loose or dense tufts with shoots 1-3 cm long. Leaves are more closely overlapping and broader at the apex. Leaves are bordered by several rows of thick-walled cells.
Salient Features
- Slender, flexuose shoots with distant leaves
- Leaves often wide spreading
- Leaves long-lanceolate with a narrowly acute apex
- Leaf margin coarsely toothed towards leaf tip
- Leaf cells pluripapillose
- Some leaves may have rhizoids emanating from the leaf apex
References
Anderson, L. E. (1951). The mosses of North Carolina VI. Encalyptaceae to Pottiaceae. The Bryologist, 54(3), 146-161
Britton, E. G. 1908. The genus Zygodon in North America. The bryologist, 11(4), 61-66
Crum, H. A., and L.E. Anderson. 1981. Mosses of Eastern North America (Vol. 1). Columbia University Press
Davison, P. G., McFarland, K. D., & Smith, D. K. 1999. RTE bryophyte survey of southern Appalachian Fraser fir forests, North Carolina, Tennessee, Virginia. Prepared for Natural Heritage Programs, North Carolina and Tennessee
Zander, R. H. 1972. Revision of the genus Leptodontium (Musci) in the New World. The Bryologist 75: 213-280
Zander, R. H. 1980. Spread of Leptodontium viticulosoides (Bryopsida) after Balsam Woolly Aphid infestation of Fraser Fir. Bull. Torrey Bot. Club 107: 7--8
Zander, R.H. 2007. Leptodontium. In: Flora of North America, North of Mexico 27: 574–576
Habitat
Leptodontium viticulosoides
A dark green expression on trunk of Fraser fir atop Clingman's Dome with Dan Pittillo looking on.
Leptodontium viticulosoides
Yellow-green to brownish is the most common color. Brownish forms can be mistaken from afar for robust clumps of Bazzania nudicaulis.
Leptodontium viticulosoides
Roan Mtn., 2018, on dead limb of living fir tree. The species appears rare on Roan Mtn.
Habitat
Leptodontium viticulosoides
September 2018. The species is abundant and luxuriant atop Clingman's Dome on numerous trunks of living Fraser fir.
Leptodontium viticulosoides
Growing in windswept fashion on trunk of fir whose bark is otherwise covered by Hypnum.
Leptodontium viticulosoides
Sept. 2018. Since 1999 a few strands have been observed growing on the upper surface of a pebbled concrete wall leading to Clingmans Dome tower.
Habit
Leptodontium viticulosoides
On horizontal, dead limb of living fir.
Leptodontium viticulosoides
On main trunk of living fir.
Leptodontium viticulosoides
In places, the stem is exposed due to the distantly spaced leaves.
Habit
Leptodontium viticulosoides
Leptodontium viticulosoides
Leptodontium viticulosoides
Long and slender, flexuose shoots challenge one's perception that this is technically an acrocarpous moss, i.e. it gives "some resemblance to a pleurocarpous habit." (Crum and Anderson 1981).
Habit
Leptodontium viticulosoides
Morphology
Leptodontium viticulosoides
Leaf margins are recurved in the lower half of the leaf.
Leptodontium viticulosoides
Leaves are narrowly decurrent.
Leptodontium viticulosoides
Each leaf cell bears several low papillae.
Morphology
Leptodontium viticulosoides
Rhizoids are often found growing from leaf apices.
Leptodontium viticulosoides vs. Zygodon viridissimus
L. viticulosoides vs. Z. viridissimus
Zygodon viridissimus is occasionally found with L. viticulosoides. In the field it differs in more closely spaced leaves that are not as narrow at their tips. The stems in the above photo of Z. viridissimus are the longest to be expected. They are usually shorter.
L. viticulosoides vs. Z. viridissimus
L. viticulosoides vs. Z. viridissimus
Leaf tips cut with a razor blade so they lay flat for photographing. Both species have papillose leaf cells and a well developed costa. Only L. viticulosoides has a serrate leaf margin.
Zygodon viridissimus
Zygodon viridissimus
