LETTERS TO THE EDITORS
The Curl Next Door
To the Editors:
In reading the article "Leaves, Flowers and Garbage Bags:
Making Waves" by Eran Sharon, Michael Marder and Harry L.
Swinney (May–June), we were struck by the similarities of the
organisms in their article to the undulate growth forms of fungi,
both in nature and when isolated into pure culture.
Field biologists will recognize the wavy-edged pileus of
Clitocybe phyllophila (Basidiomycetes: Agaricales) and
the ruffled margins and color changes used to identify the turkey
tail fungus, Trametes versicolor (Basidiomycetes:
Aphyllophorales). Plant pathogens such as wood-rotting fungi
including Grifola frondosa and Laetiporus
sulphureus (Basidiomycetes: Aphyllophorales), as well as the
conifer root-rot disease caused by Rhizina undulata
(Ascomycetes: Pezizales), also exhibit these forms.
When grown in pure culture and producing essentially one-dimensional
colonies, numerous fungi exhibit characteristically wavy margins; an
example is the mycelium of the dogwood anthracnose fungus,
Discula destructiva (Fungi Imperfecti: Coelomycetes).
Sometimes "waviness" or, in a mycological sense, undate or
undulate growth is more noticeable as sporocarps of macrofungi reach
maturity, such as in Cantharellus cibarius (Basidiomycetes: Aphyllophorales).
Waviness, twists and convolutions apparently allow the fungi to grow
to a larger size, as in the large sporocarps of cauliflower mushroom
Sparassis crispa (Basidiomycetes: Aphyllophorales).
These wavy growth forms also facilitate identification. At the
macroscopic level, therefore, the phenomenon of hyphal-tip growth
appears analogous to the meristematic growth forms discussed in the
article, despite the fungal habit typically being explained as a
preferential growth response to nutritional gradients.
Limiting their study to autotrophic lichens (dual organisms
consisting of algae and fungi) may reveal only "half the
picture" because fungal hyphae of successful saprobes,
ectomycorrhizal symbionts, plant pathogens, and endophytes may
exhibit the same phenomenon at the microscopic level. Perhaps
waviness should be of greater scientific significance than a
morphological feature within fungal phylogenies. We wonder if there
is greater consilience among fungi, fractals and frayed
configurations than the authors' first thoughts on flowers, lichens
and aquatic animals.
Eileen M. Sutker
Scott C. Redlin
U.S. Department of
Raleigh, North Carolina