Plagiochila echinata R.M. Schuster
Family: Plagiochilaceae
Synonyms
Plagiochila euryphyllon Carl subsp. echinata (R.M. Schuster) Inoue
Plagiochila sciophila Nees ex Lindenb. [as listed in Heinrichs et al. 2004]
Stotler and Crandall-Stotler (2017) accepted the name Plagiochila echinata R.M. Schuster
NatureServe Conservation Status
GNRT2
Distribution
Endemic to southeastern U.S.A. Alabama, Georgia, Kentucky, North Carolina, South Carolina, Tennessee. Restricted to the Appalachian Plateaus and Blue Ridge physiographic provinces with a single record from the Piedmont of Alabama.
Habitat
Stream ravines of cove hardwood forests; moist boulder slopes in northern hardwood forests. Moderate elevations (550 – 4500 ft). Occurring on sheltered, vertical rock walls, on ceilings of cave-like boulder crevices, in shaded rock crevices often wet from seepage and the proximity of falling water, e.g. spray cliffs of the Blue Ridge Escarpment (see Zartman and Pittillo 1998).
Occurring with a rich mix of ecological associates presumably due to optimum conditions of humidity and moisture conducive to shade loving bryophytes. Commonly found with the filmy fern Trichomanes petersii. Associated liverworts: Calypogeia muelleriana, Jubula, Lejeunea laetivirens, Metzgeria leptoneura, M. myriopoda, Plagiochila appalachiana, P. porelloides, P. sullivantii, P. virginica, Porella japonica subsp. appalachiana, Radula obconica, R. sullivantii, R. tenax. Associated mosses: Arrhenopterum heterostichum, Bartramia pomiformis, Bryoandersonia, Ctenidium molluscum, Hookeria acutifolia, Isopterygium elegans, Plagiomnium carolinianum, P. ciliare, Thamnobryum alleghaniense.
Brief Description and Tips for Identification
Forming loose mats, sometimes extensive, 20 cm or more in diameter, or as few shoots spread thinly over substrate. Shoots to 3.5 mm wide, green to brownish, shiny when dry. Leaves spreading, only slightly altered when dry, broad to the base from a wide apex. Leaf margin with teeth spinose to cilia-like.
Dioicous?. Only male plants known. Lacking any specialized means of asexual reproduction, i.e. caducous leaves and propagula lacking.
Plagiochila is known to be a difficult genus. P. echinata is most likely to be confused with P. sullivantii with which it may co-occur. Both species have spinose teeth along the leaf margin and both when dry are shiny with leaves little altered. P. sullivantii has leaves more distinctly narrowed to the base and produces caducous leaves resulting in naked stem sectors. When optimally developed, P. echinata is easily recognized by "ovate-rectangular" leaves bearing elongate teeth with the leaf apex at times bilobed "(i.e., with 2 of the apical 'teeth' commonly prominent and long drawn out)" (Schuster 1980, p. 445). Leaves of P. sullivantii are "essentially obovate to rectangular-obovate" (Schuster 1980, p. 415). A few other regional species of Plagiochila are presented in the images below.
Schuster (1959a, b, 1960), available through JSTOR, present essentially the same treatment of the Plagiochilaceae as published in Schuster (1980).
Salient Features
- Leaves are not or only slightly narrowed to the base, thus nearly rectangular in shape.
- Leaf margin with spinose to cilia-like teeth.
- Leaves shiny and little altered when dry.
- Without caducous leaves or propagula.
References
Heinrichs, J., Lindner, M., and Groth, H. 2004. Sectional classification of the North American Plagiochila (Hepaticae, Plagiochilaceae). The Bryologist, 107(4), 489-496.
Schuster, R. M. 1959a. A monograph of the Nearctic Plagiochilaceae. Part I. Introduction and sectio I. Asplenioides. The American Midland Naturalist, 62(1), 1-166.
Schuster, R. M. 1959b. A monograph of the nearctic Plagiochilaceae Part II. Sectio Zonatae through Sectio Parallelae. The American Midland Naturalist, 62(2), 257-395.
Schuster, R. M. 1960. A monograph of the nearctic Plagiochilaceae. Part III. Sectio Contiguae to conclusion. The American Midland Naturalist, 63(1), 1-130.
Schuster, R.M. 1980. The Hepaticae and Anthocerotae of North America East of the Hundredth Meridian. Volume IV. Columbia University Press, New York.
Stotler, R. E., and Crandall-Stotler, B. 2017. A synopsis of the liverwort flora of North America north of Mexico. Annals of the Missouri Botanical Garden, 102(4), 574-709.
Zartman, C. E., and Pittillo, J. D. 1998. Spray cliff communities of the Chattooga Basin. Castanea, 217-240.
Habitat
Plagiochila echinata
A boulder slope in a northern hardwood forest (Tenneesee) in which Lejeunea blomquistii, Plagiochila echinata, and P. sullivantii were found; precise locations not recorded for transfer to the above photo.
Plagiochila echinata
Occurring here with the filmy fern Trichomanes petersii and Porella japonica subsp. appalachiana.
Plagiochila echinata
An Alabama location on sandstone rock faces, Bankhead National Forest.
Habitat
Plagiochila echinata
Extensive mat of P. echinata in the center as indicated; other bryophytes labeled for ecological context.
Plagiochila echinata
Look to the right for black arrows indicating the population of P. echinata. The view is of the side of a ravine on a very steep slope.
Habit
Plagiochila echinata
A closer view of an extensive population.
Plagiochila echinata
Here many leaves appear bilobed and could be confused with Lophocolea coadunata at first glance.
Plagiochila echinata
Less robust material suggestive of P. sullivantii.
Morphology
Plagiochila echinata
Nearly rectangular leaf shape and shiny texture of a dried specimen.
Plagiochila echinata
Teeth at leaf apex are quite long.
Plagiochila echinata
A whole shoot, dorsal side up with transmitted light at two magnifications. Leaves are broad and slightly narrowed to the base.
Morphology
Plagiochila echinata
Dorsal view, shoot apex towards the right.
Plagiochila echinata
Ventral view, shoot apex towards top of photo.
Plagiochila echinata
Cells of leaf lamina with thin walls and small trigones. Oil bodies number 5-10 per cell, each oil body is composed of "minute, barely perceptible spherules" (Schuster 1980, p. 442).
Similar Taxa
Plagiochila sullivantii
Leaves are obovate, narrowed to the insertion; naked portions of stems have shed their leaves.
Plagiochila sullivantii
The plants hanging down present evidence of caducous leaves in that naked stems remain behind after leaves are shed.
Plagiochila sullivantii
In the upper left panel notice the missing leaf that fell "by design."
Similar Taxa
Plagiochila austinii
Similar to P. sullivantii in the ability to produce caducous leaves (not illustrated above). The leaves are narrow, nearly parallel sided.
Plagiochila austinii
Sharply toothed, narrow leaves. Found with P. sullivantii and P. caduciloba but apparently not yet known to occur with P. echinata.
Plagiochila austinii
The few missing leaf tips were probably browsed (eaten) by an invertebrate.
Similar Taxa
Plagiochila retrorsa
Teeth are strong. Cells at the midline of the leaf base are elongated. Formerly known as P. sharpii and thought to have been endemic to the Southern Appalachians.
Plagiochila retrorsa
Oil bodies are homogeneous, leaf cells have bulging trigones.
Plagiochila retrorsa
Shoots with ventral side facing up.
Similar Taxa
Plagiochila appalachiana
Arrows indicate fragmented leaves, a form of specialized, asexual diaspore production, i.e. once dispersed the leaf fragment may generate new plants.
Plagiochila undata
Ventral side. Leaf margins are strongly undulate and marginal teeth are few to none.
Plagiochila undata
The leaf margin leading to the dorsal insertion is strongly arched, quite unlike that of P. echinata.
Similar Taxa
Plagiochila virginica
Dentition is variable in this species, the above illustrates well devloped teeth.
Plagiochila virginica
The lumps on the leaf are propagula not fully developed.
Plagiochila virginica
Propagula fully developed.