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FAMILIES AND GENERA 341
XLIX. TELQSCHISTACEAE
PolariJocular colourless spores are the distinguishing feature of this
family as of the Caloplacaceae. Algal cells Protococcaceae. The thallus
of Teloschistaceae is more highly developed, being either foliose or fruticose,
though never attaining to very large dimensions. The cortex of Xanthoria
( foliose) is plectenchymatous, that of Teloschistes (fruticose) is fibrous. The
species of both genera are yellow- or greenish-yellow due to the presence of
the lichen-acid parietiru
Both genera have a wide distribution over the globe, more especially in
maritime regions.
Thallus foliose i. Xanthoria Th. Fr.
Thallus fruticose 2. Teloschistes Norm.
L. B CELL!ACEAE
A family of crustaceous lichens distinguished by the brown two-celled
spores. Algal cells Protococcaceae. Zahlbruckner has included here Bufllia
and Rinodina; the former with a distinctly lecideine fruit and with thinly
septate spores; the latter lecanorine and with spores of the polarilocular
type, with a very wide central septum pierced in most of the species by
a canal which may or may not traverse the middle lamella of the wall.
Rinodina is closely allied to Physciaceae, while Buellia has more affinity
with Lecideaceae and is near to Rhizocarpon.
Both genera are of world-wide distribution.
Apothecia lecideine, without a thalline margin i. Buellia De Xot.
Apothecia lecanorine, with a thalline margin 2. Rinodina MassaL
LI. PHYSCIACEAE
Thallus foliose or partly fruticose, and generally attached by rhizinae.
Algal cells Protococcaceae. The spores resemble those of Rinodina, darkcoloured
with a thick septum and reduced cell-lumina. As in that species
there may be a second septum in each cell, giving a 3-septate spore; but
that is rare.
Pyxine, a tropical or subtropical genus, is lecanorine only in the very
early stages; it soon loses the thalline margin. Anaptychia is differentiated
from Physria by the subfruticose habit though the species are nearly all
dorsiventral in structure, only a few of them being truly radiate and corticate
on both surfaces. The upper cortex of Anaptychia is fibrous, but that
character appears also in most species of Physcia either on the upper or the
lower side. Physcia and Anaptychia are widely distributed.
Thalline margin absent in apothecia
Thalline margin present in apothecia.
Thallus foliose 2. Physcia Schreb.
I. *Pyxine XyL
Thallus fruticose 3- Anaptychia Koerb.