LICHENS AND LICHEN. PARASITES

100-160p thick, a palisade of algal filaments separated by fungus pseudoparenchyma, forined of
vertical septate hyphae, about 4p in diameter, cells about 8-10,~ long; medulla a nct,work of
straiids of somewhat smaller .hyphae ; lower cortex black, appearing pseudoparenchymato~~s from
periclinal hyphae, 7-lop thick, giving rise to rhizinae below. Spothecia not seen.
The systematic position, of this specics is somewhat doubtful as no reproductive structures
have been seen; the tlialline structure of Coccocarpiu, however, is characteristic enough to
warrant clescription at this time.
011 rock with Verrucuriu obfuscuto. and Coccotror~lu kerylielensis.
ICerguelen : Observatory Bay, B.A.N.Z.A.R.E. B192-1; Murray Island, small cave about
10 ft. above shore, possibly lashed by higher sprays, B.A.N.Z.A.R.E.; Macquarie Island,
B.A.N.Z.A.lI.E., B5304.
PWROMA Ach.
Psoroma Ach. emend. Nyl., M B ~ . Soc. Imp. Sci. Nat. Cherbourg, 3, 175 ; 1855.
Lichen sect. Psoromu. Ach., Lichenogr. Suec. Prodr., 91. ; 1798.
Psoronla Ach. in Michx., F1. Bor-Amer., 2, 321 ; 1803; quoad descr. generica; Gray, Nat. Arr.
Brit., P1. 1, 444; 1821.
Pnrmelia sect. Psoroma Ach., Meth. Lich., 181 ; 1803.
Lecawa sect. Psoronta Ach., Lichenogr. Univ., 406; 1810.
Zeora sect. Psoroma Fw., Jahresber. Schles. Ges. Vaterl. Kultur, 27, 120; 1849.
Pannuria sect. Psoronru Stzbgr., Ber. Thatigk. St. Gall. Naturw., Ges., 172; 1862.
Placodium sect. Ysoronla Miill.-Arg., MBm. Soc. Phys. Hist. Nat. GenBve, 16, 377 ; 1862.
Type : Michaux, the first to use Psoroma unequivocally as a generic name, attributing it to
Acharius, repeated verbatim Acharins' description of Lichen (tribus 10) Psoroma and evidently
considered Psoroma nticrophylla (Sw.) now placed in Parnzeliella, as typical of the genus. He
also described P. palntulata as new but "propter quandam habitus affiitatem cum P. microphyllu,
ad hoc genus refero; forsan potius inter PLACODIA recensenda", hence P. palmdata
should not be taken as the type, although it is the only one described in detail in Michaux' work.
If P. ~~ticrophl/lla is taken as the type, Psoroma would replace Parmeliella Miill.-Arg., producing
much confusion of nomenclature.
In 1798, Acharius treated 11 Swedish species ancl lists 14 others not Swedish, which he may
have known only from the literature. In 1803, he transferred to Parrnelia sect. Psororna four
Swedish species and five others, one doubtfully, adding five new ones, abbreviating the sectional
description and transferring the rest of the Swedish species to Lecidea sect. Lepidoma. In 1810,
when Acharius transferred the section to Lecawa, he retained all these species of the 1803
treatment, transferring three of the 1798 treatment back from Lecidea sect. Lepidoma besides
adding new ones. In 1814, he retained the 1803 treatment of the original species, although
making some changes in other species of the 1810 treatment. Hence we have to consider: Lichen
lI?jpno~um, L. candelaritcs, L. squamulostis, L. cartilugineus, L. crassus, L. chrysolducos, and
L. rubinus, in choosing a type.
Tn 1821, Gray again raised Psoroma to generic rank, treating P. crasstim, P. candelarium and
P. Hypnortcm of the original Acharian concept and L. squamulos?ls Schrad. as a synonym of his
P. cervintis (Pers.) instead of Lichen baditis Ach. non Pers. where Acharius had placed it. In
1855, Nylander restricted the genus to the present concept, treating P. Hypnortem, P. sphinctrintcm
(Mont.) and P. pdaceum (Fr.). Since Lichen Hypnurum Vahl is common to all treatment8
'