Online Articles
about nature - by Boyd
Shaffer,
artist /naturalist
Observations
of a Naturalist
This Article: Those Amazing Lichens - a symbiotic relationship (pg 1 of 5) PAGES: 1 - 2 - 3 - 4 - 5
Lichen
structures are composed of both algae and fungi
living together in a symbiotic relationship. There
are acids present which can help identify certain
species, but not always. Observe the growth forms,
color when wet and dry and under what condition it
grows. A hand lens and a dissecting microscope are
indispensable tools for the student attempting to
study lichens. Following are nomenclatures with new
words and the translations that one must know and
understand. They
are extremely small, and will not be
used for identification in this
article. Soredia
are clumped soralia, which are
small reproductive bodies. They
are reproductive bodies which allow the
spores to be dispersed at a higher
elevation, even though it might be only
one half inch. Description:
Thallus large, grayish green when dry,
bright green when wet, and lighter
colored when found in open sunny
locations. There are scattered, rounded
pores on the upper surface. Undersides
with black rhizines (root-like
structures) appearing vein-like (A).
Thallus often forming large, rounded
leafy rosettes. Habitat/s:
On moss in mixed woods or dense
forests. Range:
All of South Central Alaska Description:
Thallus light grayish when wet or
dry Habitat/s:
On soil, logs, moss, and along creek
banks. Range:
All of South Central Alaska Description:
Light green to brownish gray-green with
large black or brown apothecia on most
lobes. This species has heavy vein-like
structures on the underside which are
evident form the upper side as
illustrated. Habitat/s:
On open soil, occurs rarely on moss and
logs. Range:
All of South Central Alaska Description:
Thallus light Gray to brownish.
Apothecia large and black, on tips of
lobes. An unmistakable
species. Habitat/s:
Found on moss and open soil. Range:
All of South Central Alaska Description:
Thallus brownish turning dark
green when wet. The lobes are turned up
at their tips. The whole lichen is very
brittle when dry. The lower surface is
dark becoming light near tip and edges.
Habitat/s:
Found in open areas growing in grass.
Meadows are likely places to hunt for
this species. Range:
All of South Central Alaska
OBSERVATIONS
INDEX
Lichens PAGES: 1
- 2
- 3
- 4
- 5
Lichen
Nomenclature:
Apothecia
are reproductive bodies of the fungal
part of a lichen. These are often
caused by a cup fungi present in the
lichen. The apothecia are often raised
in the center and brown, gray, red or
black.
Illustrated
at left are but a few of the major
shapes encountered when studying
lichens.
These
are hair-like and root-like structures
beneath the thallus of many species.
Most common in Peltigera.
Small
hair-like growth along the
thallus edge is a good
identifying feature.
The
hypha of a fungus consists of
many strands of individual cells.
These
are very small and can only be observed
with a hand lens or microscope.
Scattered over a thallus surface they
have many different shapes, helpful to
identification
Soredia
growing dotted near the thallus margine
will be helpful when identifying some
species.
These,
usually upright stalks, come from
squamulose growths on the
substrate.
Squamulose
lichens can be very densely covered
with squamules. Some genera, such as
Stenocaulon, are made up of nothing but
squamules. The primary thallus in
cladonia is made up of these. Examine
the substrate below a cladonia podetia.
Many
lichens have soredia along the outer
edges or along the veins assisting in
the identification of the species.
Soredia can be red, white, blue, black,
brown or green.
Group
1. Thallus broad, leaf-like, growing on moss or
bare earth, some types forming rosettes.
Name:
Peltigera apthosa (Figure 1/2
life size)
Name:
Peltigera spuria (Figure
1/2 life size)
(A) Underside
light tan with small light colored
rhizines
(B) Apothecia
(rounded, small reproductive
structures) on upper surface not
usually found.
Name:
Peltigera venosa (Figure about
twice life size)
Name:
Peltigera polydactyla (Figure about
life size)
- Continued
on PAGE 2
-
Name:
Peltigera malacea Figure 1/4 life
size