PDF - CES (IISc)

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126 MORPHOLOGY
V. STRUCTURES PECULIAR TO LICHENS
i. AERATION STRUCTURES
A. CYPHELLAE AND PSEUDOCYPHELLAE
The thallus of Stictaceae has been regarded by Nylander 1
and others as
one of the most highly organized, not only on account of the size attained
by the spreading lobes, but also because in that family are chiefly found
those very definite cup-like structures which were named "cyphellae" by
Acharius 2 . They are small hollow depressions about \ mm. or more in
width scattered irregularly over the under surface of the thallus.
a. HISTORICAL. Cyphellae were first pointed out by the Swiss botanist,
Haller 3 . In his description of a lichen referable to Sticta fuliginosa he
"
describes certain white circular depressions to be found among the short
brown hairs of the under surface." At a later date Schreber 4 made these
" white excavated points " the leading character of his lichen genus Sticta.
In urceolate or proper cyphellae, the base of the depression rests on the
medulla; the margin is formed from the ruptured cortex and projects slightly
inwards over the edge of the cup. Contrasted with these are the pseudo-
cyphellae, somewhat roundish openings of a simpler structure which replace
the others in many of the species. They have no definite margin ; the inter-
nal hyphae have forced their way to the exterior and form a protruding
tuft slightly above the surface. Meyer 5 reckoned them all among soredia;
but he distinguished between those in which the medullary hyphae became
conglutinated to form a margin (true cyphellae) and those in which there
was a granular outburst of filaments (pseudocyphellae). He also included
a third type, represented in Lobaria pulmonaria on the under surface of
which there are numerous non-corticate, angular patches where the pith is
laid bare (Fig. 72). Delise 6
, writing about the same time on the Sticteae,
gives due attention to their occurrence, classifying the various species of
Sticta as cyphellate or non-cyphellate.
Acharius had limited the name " cyphella " to the hollow urceolate bodies
that had a well-defined margin. Nylander 7 at first included under that
term both types of structure, but later 8 he classified the pulverulent " soredia-
like " forms in another group, the pseudocyphellae. As a rule they bear no
relation to soredia, and algae are rarely associated with the protruding
filaments. Schwendener 9 and later Wainio , 10
Sticta aurata from
, in describing
Brazil, state, as exceptional, that the citrine-yellow pseudocyphellae of that
species are sparingly sorediate.
1
Nylander 1858, p. 63.
4 Schreber 1791, p. 768.
8
Nylander 1860, p. 333.
'
2
Acharius 1810, p. 12. 3 Haller 1768, p. 85.
6 Meyer 1825, p. 148.
9 Schwendener 1863, p. 169.
s Delise 1822. 7 Nylander 1858, p. 14.
10 Wainio 1890, I. p. 183.