Moss phyllid morphology varies systematically with substrate slope
cover image of Plant Ecology and Evolution 154(3)

Supplementary Files

Supplementary file 1
Supplementary file 2
Supplementary file 3
Supplementary file 4
Supplementary file 5


desiccation resistance
Ornstein-Uhlenbeck process
phylogenetic comparative method
phyllid morphology

How to Cite

Turberville, C., Fuentes-González, J., Rogers, S. and Pienaar, J. (2021) “Moss phyllid morphology varies systematically with substrate slope”, Plant Ecology and Evolution, 154(3), pp. 419-431. doi: 10.5091/plecevo.2021.1839.


Background and aims – Tracheophyte leaf morphology is well studied but it is unclear if the findings generalize to poikilohydric plants. We tested combinations of hypotheses to determine if microhabitat characteristics, including light exposure, moisture availability, and substrate slope, controlled for morphological differences between upright and prostrate growth forms, affect phyllid surface area and costa length of mosses.
Material and methods – We quantified mean phyllid surface-area and costa lengths for four replicates of 38 moss species from Alabama. Phylogenetic comparative methods that model adaptation were used to evaluate the relative evidence for each hypothesis using information criteria. To further explore mechanistic explanations involving substrate slope, we tested whether mosses on vertical substrates differed from those on horizontal substrates in the average amount of water-retaining, nutrient-rich litter they accumulated.
Key results – Substrate slope and growth form combined were the best predictors of phyllid surface area. Mosses growing on vertical substrates exhibited smaller phyllid surface area for both growth forms. Although growth form and phyllid length best explained costa length variation, a more complex model including substrate slope performed nearly as well. Within the prostrate growth forms, species growing on vertical substrates exhibit longer relative costa than those on horizontal substrates. We also estimated rapid rates of adaptation for both traits.
Conclusion – The smaller phyllid surface area of both upright and prostrate growth forms is possibly an adaptive response to reduced habitat moisture-retention or nutrient quality that vertical substrates offer. The longer costa lengths of prostrate mosses growing on vertical surfaces relative to prostrate mosses on horizontal surfaces, possibly make up for the decreased ability of smaller phyllids to rapidly reabsorb water when it is available. Further work is required to determine if it is truly substrate slope itself that matters or other variables associated with the differences in slope, and to determine how general this phenomenon is.


Bartoszek K., Pienaar J., Mostad P., Andersson S. & Hansen T.F. 2012. A phylogenetic comparative method for studying multivariate adaptation. Journal of Theoretical Biology 314: 204–215.

Belda M., Holtanová E., Halenka T. & Kalvová J. 2014. Climate classification revisited: from Köppen to Trewartha. Climate Research 59(1): 1–13.

Bell G. 1982. Leaf morphology of arid-zone moss species from South Australia. Journal of the Hattori Botanical Laboratory 53: 147–151.

Bond-Lamberty B. & Gower S.T. 2007. Estimation of stand-level leaf area for boreal bryophytes. Oecologia 151(4): 584–592.

Burnham K.P. & Anderson D.R. 2002. Model selection and multimodel inference: a practical information-theoretic approach. Second edition. Springer, New York.

Butler M.A. & King A.A. 2004. Phylogenetic comparative analysis: a modeling approach for adaptive evolution. The American Naturalist 164(6): 683–695.

Cho Y.Y., Oh S., Oh M.M. & Son J.E. 2007. Estimation of individual leaf area, fresh weight, and dry weight of hydroponically grown cucumbers (Cucumis sativus L.) using leaf length, width, and SPAD value. Scientia Horticulturae 111(4): 330–334.

CNABH 2020. Consortium of North American Bryophyte Herbaria portal. Available from [accessed 8 Aug. 2020].

Deutsch E.S., Bork E.W. & Willms W.D. 2010. Separation of grassland litter and ecosite influences on seasonal soil moisture and plant growth dynamics. Plant Ecology 209(1): 135–145.

Donovan L.A., Maherali H., Caruso C.M., Huber H. & de Kroon H. 2011. The evolution of the worldwide leaf economics spectrum. Trends in Ecology & Evolution 26(2): 88–95.

Dormaar J. & Carefoot J. 1996. Implications of crop residue management and conservation tillage on soil organic matter. Canadian Journal of Plant Science 76(4): 627–634.

Dyksterhuis E. & Schmutz E. 1947. Natural mulches or “litter” of grasslands: with kinds and amounts on a southern prairie. Ecology 28(2): 163–179.

eFloras 2020. eFloras portal. Available from [accessed 10 Aug. 2020].

Espinosa F. & Pinedo Castro M. 2018. On the use of herbarium specimens for morphological and anatomical research. Botany Letters 165(3–4): 361–367.

Fernandez-Marin B., Holzinger A. & García-Plazaola J.I. 2016. Photosynthetic strategies of desiccation-tolerant organisms. Handbook of Photosynthesis 38: 719–737.

Flowers S., Patterson P.M., Wynne F.E. & Conard H.S. 1945. The bryophyte herbarium. A moss collection: preparation and care. The Bryologist 48(4): 198–202.

Frahm J. 1978. Mosses and liverworts of the Sahara. Nova Hedwigia 30: 527–548.

Franks P. & Brodribb T.J. 2005. Stomatal control and water transport in the xylem. In: Holbrook N.M. & Zwieniecki M.A. (eds) Vascular transport in plants. Physiological ecology vol. 1: 69–89. Elsevier, Oxford.

Geffert J.L., Frahm J., Barthlott W. & Mutke J. 2013. Global moss diversity: spatial and taxonomic patterns of species richness. Journal of Bryology 35(1): 1–11.

Glime J.N. 2007. Bryophyte ecology. Volume I: physiological ecology. Michigan Technological University and the International Association of Bryologists. Available from [accessed 10 Sep. 2020].

Guerra J., Martínez-Sánchez J. & Ros R. 1992. On the degree of adaptation of the moss flora and vegetation in gypsiferous zones of the south-east Iberian Peninsula. Journal of Bryology 17(1): 133–142.

Hansen T.F. 1997. Stabilizing selection and the comparative analysis of adaptation. Evolution 51(5): 1341–1351.

Hansen T.F., Pienaar J. & Orzack S.H. 2008. A comparative method for studying adaptation to a randomly evolving environment. Evolution: International Journal of Organic Evolution 62(8): 1965–1977.

Hansen T.F. 2012. Adaptive landscapes and macroevolutionary dynamics. In: Svensson E. & Calsbeek R. (eds) The adaptive landscape in evolutionary biology. Oxford University Press, Oxford.

Haughian S.R. & Frego K.A. 2017. Log moisture capacity does not predict epixylic bryophyte growth under thinned and unthinned forest canopies. Functional Ecology 31(8): 1540–1549.

Herbert J. & Caudill J.A. 2012. Assessing climate change in Alabama using climate normals. Geographical Bulletin 53(2): 111.

Heijmans M.M.P.D., Arp W.J. & Chapin III F.S. 2004. Controls on moss evaporation in a boreal black spruce forest. Global Biogeochemical Cycles 18: GB2004.

Holland E. & Coleman D.C. 1987. Litter placement effects on microbial and organic matter dynamics in an agroecosystem. Ecology 68(2): 425–433.

Horn H.S. 1971. The adaptive geometry of trees. Princeton University Press, Princeton.

Huttunen S., Bell N. & Hedenäs L. 2018. The evolutionary diversity of mosses–taxonomic heterogeneity and its ecological drivers. Critical Reviews in Plant Sciences 37(2–3): 128–174.

Kopperud B.T., Pienaar J., Voje K.L., Orzack S.H., Hansen T.F. & Grabowski M. 2020. Package ‘slouch.’ Stochastic Linear Ornstein-Uhlenbeck Comparative Hypotheses. v.2.1.4. Available from [accessed 26 Jun. 2020].

La Farge-England C. 1996. Growth form, branching pattern, and perichaetial position in mosses: cladocarpy and pleurocarpy redefined. The Bryologist 99(2): 170–186.

McKnight K.B., Rohrer J.R., Ward K.M. & Perdrizet W.J. 2013. Common mosses of the Northeast and Appalachians. Volume 86. Princeton University Press, Princeton.

Meeuwig R.O. 1970. Infiltration and soil erosion as influenced by vegetation and soil in northern Utah. Rangeland Ecology & Management/Journal of Range Management Archives 23(3): 185–188.

Morris J.L., Puttick M.N., Clark J.W., et al. 2018. The timescale of early land plant evolution. Proceedings of the National Academy of Sciences of the United States of America 115(10): E2274–E2283.

Niinemets Ü. & Tobias M. 2019. Canopy leaf area index at its higher end: dissection of structural controls from leaf to canopy scales in bryophytes. New Phytologist 223: 118–133.

Nicotra A.B., Leigh A., Boyce C.K., et al. 2011. The evolution and functional significance of leaf shape in the angiosperms. Functional Plant Biology 38(7): 535–552.

Oberndorfer E.C. 2006. Plant, macrolichen and moss community structure and species richness in the coastal barrens of Nova Scotia. MSc thesis, Saint Mary’s University, Halifax, Canada.

Pagel M. 1999. The maximum likelihood approach to reconstructing ancestral character states of discrete characters on phylogenies. Systematic Biology 48(3): 612–622.

Paradis E., Claude J. & Strimmer K. 2004. APE: analyses of phylogenetics and evolution in R language. Bioinformatics 20(2): 289–290.

Pope R. 2016. Mosses, liverworts, and hornworts: a field guide to common bryophytes of the northeast. Comstock Publishing Associates, a division of Cornell University Press.

Priddle J. 1979. Morphology and adaptation of aquatic mosses in an Antarctic lake. Journal of Bryology 10(4): 517–529.

Proctor M.C.F. 1979. Structure and eco-physiological adaptations in bryophytes. Bryophyte Systematics 14: 479–509.

Proctor M.C.F. 1982. Physiological ecology: water relations, light and temperature responses, carbon balance. In: Smith A.J.E. (ed.) Bryophyte ecology: 333–381. Chapman and Hall, London.

Proctor M.C.F 2000. Physiological ecology. Bryophyte Biology 2: 237–268.

Proctor M.C.F. & Tuba Z. 2002. Poikilohydry and homoihydry: antithesis or spectrum of possibilities? New Phytologist 156(3): 327–349.

Proctor M.C.F., Oliver M.J., Wood A.J., et al. 2007. Desiccation-tolerance in bryophytes: a review. The Bryologist 110(4): 595–621.

R Core Team 2013. R: a language and environment for statistical computing. R Foundation for Statistical Computing, Vienna. Available from [accessed 26 Jun. 2020].

Rauzi F. 1960. Water-intake studies on range soils at three locations in the Northern Plains. Rangeland Ecology & Management/Journal of Range Management Archives 13(4): 179–184.

Rice S.K., Collins D. & Anderson A.M. 2001. Functional significance of variation in bryophyte canopy structure. American Journal of Botany 88(9): 1568–1576.

Rice S.K., Aclander L. & Hanson D.T. 2008. Do bryophyte shoot systems function like vascular plant leaves or canopies? Functional trait relationships in Sphagnum mosses (Sphagnaceae). American Journal of Botany 95: 1366–1374.

Rice S.K., Neal N., Mango J. & Black K. 2011. Relationships among shoot tissue, canopy and photosynthetic characteristics in the feathermoss Pleurozium schreberi. The Bryologist 114: 367–378.

Rice S.K., Gagliardi T.A. & Krasa R.A. 2018. Canopy structure affects temperature distributions and free convection in moss shoot systems. American Journal of Botany 105(9): 1499–1511.

Rose J.P., Kriebel R. & Sytsma K.J. 2016. Shape analysis of moss (Bryophyta) sporophytes: insights into land plant evolution. American Journal of Botany 103(4): 652–662.

Rouphael Y., Mouneimne A., Ismail A., Mendoza-De Gyves E., Rivera C. & Colla G. 2010. Modeling individual leaf area of rose (Rosa hybrida L.) based on leaf length and width measurement. Photosynthetica 48(1): 9–15.

Scheirer D.C. 1983. Leaf parenchyma with transfer cell‐like characteristics in the moss, Polytrichum commune Hedw. American Journal of Botany 70(7): 987–992.

Schneider C.A., Rasband W.S. & Eliceiri K.W. 2012. NIH Image to ImageJ: 25 years of image analysis. Nature Methods 9(7): 671–675.

Schofield W. 1981. Ecological significance of morphological characters in the moss gametophyte. The Bryologist 84(2): 149–165.

Streeter D.T. 1970. Bryophyte ecology. Science Progress 58: 419–434.

Shaw A.J. & Goffinet B. 2000. Bryophyte biology. Cambridge University Press, Cambridge.

Stewart K.J. & Mallik A.U. 2006. Bryophyte responses to microclimatic edge effects across riparian buffers. Ecological Applications 16(4): 1474–1486.

Thomas R.J., Ryder S.H., Gardner M.I., Sheetz J.P. & Nichipor S.D. 1996. Photosynthetic function of leaf lamellae in Polytrichum commune. The Bryologist 99: 6–11.

Vitt D.H. & Buck W.R. 2019. Key to the moss genera of North America and Mexico. In: Flora of North America Editorial Committee (eds) Flora of North America North of Mexico [online], vol. 28. Available from [accessed 3 Oct. 2020].

Vitt D.H. & Glime J.N. 1984. The structural adaptations of aquatic Musci. Lindbergia 10: 95–110.

Waite M. & Sack L. 2010. How does moss photosynthesis relate to leaf and canopy structure? Trait relationships for 10 Hawaiian species of contrasting light habitats. New Phytologist 185(1): 156–172.

Weaver J.E. & Rowland N. 1952. Effects of excessive natural mulch on development, yield, and structure of native grassland. Botanical Gazette 114(1): 1–19.

Whitehead D. & Gower S. T. 2001. Photosynthesis and light-use efficiency by plants in a Canadian boreal forest ecosystem. Tree Physiology 21(12–13): 925–929.

Wright I.J., Reich P.B., Westoby M., et al. 2004. The worldwide leaf economics spectrum. Nature 428(6985): 821–827.

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.