02-07-2003, 03:13 AM
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Are Lichens Plants?
In article ,
wrote...
I know we sometimes discuss lichens here. Not that I would tell anyone not to.
They are a symbiotic combination of a fungus and an alga.
But the lichen species is the fungal species. Many species of lichens
share fewer species of algal symbiont.
Are they still
considered plants? Is lichenology still a branch of botany? What about
mycology?
Sure, why not? They're traditional branches of the field. Lichens at
least are "plantlike organisms". Okay, I suppose it depends entirely
on what a given speaker means by "plants". It needn't be a taxonomic
or phylogenetic term, and scientific disciplines like "botany" needn't
be restricted to single clades.
For that matter, not all fungi are related to other fungi, and some
lichens aren't related to the other lichens.
If we want to restrict "plant" to the narrower phylogenetic group
containing the familiar green land plants and their kin, then not only
lichens but also most algae aren't "plants". [Well, at least some green
algae are closely related to land plants, but green plants, red algae
and brown algae, etc aren't at all related to one another as plantlike
organisms].
On the other hand, if someone wants to call lichens "plants", he really
should make it very clear that they're not related to more typical "
plants".
There's something to be said for using the formal group names:
Lecanorales, Ascomycota, Chlorophyta, Embryophyta, Rhodophyta, Phaeophyta,
when precision is needed, and keeping "plant" as an informal, unscientific
term.
http://tolweb.org/tree?group=Eukaryotes&contgroup=Life
cheers
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