Hostname: page-component-586b7cd67f-2brh9 Total loading time: 0 Render date: 2024-11-24T15:24:09.592Z Has data issue: false hasContentIssue false
  • English
  • Français

Diffuse growth in the fruticose beard lichen Ramalina usnea (L.) R. Howe

Published online by Cambridge University Press:  29 January 2015

William B. SANDERS  and
Sherzod A. TOKAMOV
William B. SANDERS
Affiliation:
Department of Biological Sciences, Florida Gulf Coast University, Fort Myers, FL 33965-6565, USA. Email: wsanders@fgcu.edu
Sherzod A. TOKAMOV
Affiliation:
Department of Biological Sciences, Florida Gulf Coast University, Fort Myers, FL 33965-6565, USA. Email: wsanders@fgcu.edu
Get access Rights & Permissions [Opens in a new window]

Abstract

Very little is known about how growth is distributed within thalli of fruticose lichens. To determine whether mature, non-apical regions of the beard lichen Ramalina usnea elongate, segments of the broadest axes were marked with thread and measured; thalli were then returned to the field to resume growth for about one year. Growth was evident in all segments measured and increments were roughly proportional to length, suggesting that elongation occurs throughout the thallus. New thallus axes (branches) were organized from buds that emerged from mature tissue, usually along pseudocyphellae and surfaces exposed by breakage. Axes were very fine at their extremities and possessed an inrolled apex from the time of bud emergence. No evidence of apical branching was observed. The thallus cortex consisted of very thick-walled fungal cells oriented longitudinally. In transverse section, cells gave the appearance of being grouped within fascicles, indicating that branch cells grow within the older cell wall material of their neighbours, as occurs in the cortex of Ramalina menziesii and the medullary cord of Usnea longissima. A continued accumulation of cell wall layers may be related to the mature tissue's capacity to sustain elongation growth.

Keywords

apical growthbranchingintercalary growthlichen development
Type
Articles
Information
The Lichenologist , Volume 47 , Issue 1 , January 2015 , pp. 51 - 58
Copyright
Copyright © British Lichen Society 2015 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Anglesea, D., Greenhalgh, G. N. & Veltkamp, C. J. (1983) The structure of the thallus tip in Usnea subfloridana . Lichenologist 15: 81–88.Google Scholar
Armstrong, R. A. & Smith, S. N. (1998) Does radial growth of the lichen Parmelia conspersa depend exclusively on growth processes at the lobe tip? Environmental and Experimental Botany 39: 263–269.Google Scholar
Boissière, M.-C. (1979) Cytologie du Peltigera canina en microscopie électronique: le micobionte à l'état végétatif. Révue de Micologie 43: 1–70.Google Scholar
Boucher, V. L. & Nash, T. H. III (1990) Growth patterns in Ramalina menziesii in California: coastal vs. inland populations. Bryologist 93: 295–302.Google Scholar
Brodo, I. M., Sharnoff, S. D. & Sharnoff, S. (2001) Lichens of North America. New Haven & London: Yale University Press.Google Scholar
Cramer, C. (1891) Über das Verhaeltniss von Chlorodictyon foliosum J. Ag. (Caulerpeen) und Ramalina reticulata (Noehden) Krplhb. (Lichenen). Berichte der Schweizerischen botanischen Gesellschaft 1: 100–123.Google Scholar
Fisher, P. J. & Proctor, M. C. F. (1978) Observations on a season's growth in Parmelia caperata and P. sulcata in South Devon. Lichenologist 10: 81–89.Google Scholar
Greenhalgh, G. N. & Anglesea, D. (1979) The distribution of algal cells in lichen thalli. Lichenologist 11: 283–292.Google Scholar
Hale, M. E. (1970) Single-lobe growth-rate patterns in the lichen Parmelia caperata . Bryologist 73: 72–81.CrossRefGoogle Scholar
Hale, M. E. (1979) How to Know the Lichens, 2nd edn. Dubuque, Iowa: William C. Brown.Google Scholar
Henssen, A. & Dobelmann, A. (1987) Development of the spongiostratum in Anzia and Pannoparmelia . Bibliotheca Lichenologica 25: 103–108.Google Scholar
Herre, A. C. (1904) The growth of Ramalina reticulata . Botanical Gazette 38: 218–219.Google Scholar
Hill, D. J. (1994) The cell cycle of the photobiont of the lichen Parmelia sulcata (Lecanorales, Ascomycotina) during development of the thallus lobes. Cryptogamic Botany 4: 270–273.Google Scholar
Honegger, R. (2008) Morphogenesis. In Lichen Biology, 2nd Edition (Nash, T. H. III, ed.): 69–93. Cambridge: Cambridge University Press.Google Scholar
Jansson, K. U., Palmqvist, K. & Esseen, P.-A. (2009) Growth of the old forest lichen Usnea longissima at forest edges. Lichenologist 41: 663–672.Google Scholar
Kashiwadani, H. (1990) Some Chilean species of the genus Ramalina (lichens). Bulletin of the National Science Museum, Tokyo, Series B 16 (1): 1–12.Google Scholar
Kashiwadani, H. & Nash, T. H. III (2004) Ramalina. In Lichen Flora of the Greater Sonoran Desert Region, Vol. 2 (Nash, T. H. III, Ryan, B. D., Diederich, P., Gries, C. & Bungartz, F., eds): 440–455. Tempe, Arizona: Lichens Unlimited, Arizona State University.Google Scholar
Keon, D. B. & Muir, P. S. (2002) Growth of Usnea longissima across a variety of habitats in the Oregon Coast Range. Bryologist 105: 233–242.CrossRefGoogle Scholar
Larson, D. W. (1983) Morphological variation and development in Ramalina menziesii Tayl. American Journal of Botany 70: 668–681.Google Scholar
Lutz, K. G. (1894) Ueber die sogenannte Netzbildung bei Ramalina reticulata Krplhbr. Berichte der Deutschen Botanischen Gesellschaft 12: 207–214.Google Scholar
Peirce, G. J. (1898) On the mode of dissemination and on the reticulations of Ramalina reticulata . Botanical Gazette 25: 404–417.Google Scholar
Rolstad, J. & Rolstad, E. (2008) Intercalary growth causes geometric length expansion in Methuselah's beard lichen (Usnea longissima). Botany 86: 1224–1232.Google Scholar
Rundel, P. (1978) Evolutionary relationships in the Ramalina usnea complex. Lichenologist 10: 141–156.Google Scholar
Sanders, W. B. (1989) Growth and development of the reticulate thallus in the lichen Ramalina menziesii . American Journal of Botany 76: 666–678.Google Scholar
Sanders, W. B. (1992) Comparative in situ studies of thallus net development in morphologically distinct populations of the lichen Ramalina menziesii . Bryologist 95: 192–204.Google Scholar
Sanders, W. B. (1993) Apical formation of cilia and associated branching of the axis in the lichen Teloschistes flavicans . International Journal of Plant Sciences 154: 75–79.Google Scholar
Sanders, W. B. & Ascaso, C. (1995) Reiterative production and deformation of cell walls in expanding thallus nets of the lichen Ramalina menziesii (Lecanorales, Ascomycetes). American Journal of Botany 82: 1358–1366.Google Scholar
Sanders, W. B. & de los Ríos, A. (2012) Development of thallus axes in Usnea longissima (Parmeliaceae, Ascomycotina), a fruticose lichen showing diffuse growth. American Journal of Botany 99: 998–1009.Google Scholar