HUNTIA A Journal of botanical History VolUme 13 NUmber 2 2007 Hunt Institute for botanical Documentation Carnegie mellon University Pittsburgh The Hunt Institute for botanical Documentation, a research division of Carnegie mellon University, specializes in the history of botany and all aspects of plant science and serves the international scientific community through research and documentation. To this end, the Institute acquires and maintains authoritative collections of books, plant images, manuscripts, portraits and data files, and provides publications and other modes of information service. The Institute meets the reference needs of botanists, biologists, historians, conservationists, librarians, bibliographers and the public at large, especially those concerned with any aspect of the North American flora. Huntia publishes articles on all aspects of the history of botany, including exploration, art, literature, biography, iconography and bibliography. 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Hunt Institute for botanical Documentation Carnegie mellon University 5000 Forbes Avenue Pittsburgh, PA 15213-3890 Telephone: 412-268-2434 email: [email protected] Web site: http://huntbot.andrew.cmu.edu/ HIbD/Publications/HI-Pubs/Pub-Huntia.shtml editor and layout Scarlett T. Townsend book reviews and Announcements editor Charlotte A. Tancin Associate editors Gavin D. r. bridson T. D. Jacobsen Angela l. Todd Frederick H. Utech James J. White Designer Lugene b. bruno Photographer Frank A. reynolds Printed and bound by RR Donnelley, Hoechstetter Plant, Pittsburgh, Pennsylvania © 2007 Hunt Institute for botanical Documentation All rights reserved ISSN 0073-4071 Huntia 13(2) 2007 Signposts to symbiosis: a review of early attempts to establish the constitution of lichens M. E. Mitchell Abstract until the latter half of the 1860s, botanists had he created a genus Lichen (1:437–438) to assumed that fungi growing in or on living plants accommodate such of the plants in question as behaved solely as parasites prospering at the expense 1 of their hosts. Because host organisms are often exhibited similar fruit morphology. Five years characterized by conspicuous decline and early death, later, a corresponding category was introduced such associations were widely regarded as synonymous in the third volume of Robert Morison’s with disease and transience. Consequently, when the Plantarum Historiae Universalis Oxoniensis; this suggestion was advanced in 1866 that, rather than being the autonomous plants they seemed, lichens — long a volume was completed over an eight-year symbol of vigor and durability — are the product of period following Morison’s death in 1683 by alliances between microscopic algae and fungi, few Jacob Bobart (1641–1719), superintendent of botanists were prepared to entertain the notion. But the university’s physic garden. While Bobart a presumption of algal and fungal participation in the composition of lichens was not, in fact, altogether new: was aware of the generic name proposed by 18th-century botanists had been aware of this possibility tournefort, he chose not to use it, preferring to the extent that some contemporary systematists had to describe his 50-odd species (Morison assigned lichens to the algae, others to the fungi. Early 1680–1699, 3:631) as “Moss-Fungi” (“Musco- in the following century, however, that awareness had 2 been rapidly eclipsed by a perception of lichens as plants Fungos”). in the event, the name proposed by distinct from either of those groups. though results soon Bobart yielded to that of tournefort, but its began to appear that were at odds with this view, these evocation of fungal affinity endured. were either ignored or argued away. Evidence that algae the first botanist to state that fungi and and fungi do contribute to the formation of certain lichen thalli continued nonetheless to accumulate, until the lichens are related was antoine de Jussieu concept of autonomy, which had prevailed for 50 years, (1686–1758), a successor to tournefort at the eventually became no longer reasonably sustainable. this Jardin du Roi. in a paper presented to the paper details the reporting of that evidence and reveals académie Royale des Sciences, Jussieu (1730, how a shadow that had flickered in the minds of botanists for over 150 years finally gained substance. p. 377) remarked apropos of fungi that “if one looks in the classes of plants for a genus they resemble and to which they may be Introduction compared, the only one found is Lichen,” and When Joseph de tournefort (1656–1708), he further observed (p. 378) that fungi and professor of botany at the Jardin du Roi, came to lichens “show an almost identical method of 3 prepare his Elemens de Botanique (1694), several producing their seed.” Jussieu’s comments do quite unrelated plants had been categorized not, however, appear to have at all attracted the 4 as lichens. that anomaly led tournefort to attention of contemporary botanists — when attempt a scientific delimitation of the group: Linnaeus came to deal with the lichens, he assigned them not to his order Fungi but, Department of Botany, national university of with a few exceptions, to the algae (1753, ireland, Galway, ireland 2:1140–1156). 101 102 Huntia 13(2) 2007 after ten years in their Linnaean home, the Verrucariae can be taken for Sphaeria.”8 lichens were again on the move: the French also in the 1790s, the possibility was again botanist Michel adanson (1727–1806) raised that lichens are in some way related to combined them with the fungi in his attempt algae: the French abbé and botanist Etienne at a natural classification (1763–1764, 2:6–7), Ventenat (1757–1808) — influenced perhaps but that bid to establish the systematic position by Haller — queried (1799, 2:36) whether of lichens found no immediate support. the “gelatinous lichens might not be instances of Swiss polymath albrecht von Haller (1708– Nostoc having changed appearance.”9 1777) preferred to accommodate them in a at the opening of the 19th century, distinct class “Lichenes,” one subdivision of therefore, botanists recognized that algae are which he designated “Lichenes Gelatinosi. somehow associated with the development of nostoch” (1768, 3:94); Haller thus became certain lichens, and fungi with that of others. the first to provide a collective name for that ten years later, however, in consequence of distinctive group of lichens and to associate an uncompromising statement by the Swedish them with an algal genus.5 no further inklings lichenologist Erik acharius (1757–1819), of a relationship between lichens and either botanists largely abandoned that view. in his algae or fungi appear to have been reported authoritative Lichenographia Universalis (1810, until the late 1780s when the austrian p. 14), acharius declared cryptogamist Johann Hedwig (1730–1799) to summarize from a complete and careful referred (1787–1797, 2:[i]) to the bond examination of all the parts, i have concluded (“nexum”) that he considered to exist between that lichens represent a special, natural, group fungi and lichens.6 in the same work (p. 3) separate from other cryptogamic plants and distinguished by the following arrangement: Hedwig reported his conviction, based on the general receptacle (thallus) polymorphic, internal structure of certain lichen fruit bodies, rootless, lacking a stem, perennating, that there is “substantial correspondence with extremely small propagative bodies between lichens and the Pezizas of Linnaeus (gongyles) as much dispersed through all its substance — internally, externally and or Elvelas of Gleditsch … certainly, everything plentifully in cavities — as enclosed in distinct, properly considered, the complete conformity colored, carpomorphic organs (partial and affinity of all these is not to be denied — to receptacles or apothecia). it is evident from the the extent that if plants of this genus [Lichen] arrangement indicated that, by their receptacles of double structure together with their different were to find a place among the fungi, then forms and nature, lichens remain quite distinct the fungi should in the same way be linked from algae, hepatics and fungi.10 to lichens in the systematic arrangements of botanists.”7 this categoric statement from so influential a Evidence of such a link had likewise source was to cast a long shadow: for 50 years been observed by the mycologist Christiaan the concept of lichen autonomy led botanists Persoon (1761–1836), a Capetonian of Dutch/ to ignore growing evidence of algal and fungal German parentage. He commented (1794, participation in lichen development. p. 7) that “no plants have fruits more similar to those of fungi than lichens; if the crust is Findings incompatible with autonomy ignored, the scutellate [apotheciate] lichens