314 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



several species, grouped under the general name of tripe de roche, 

 have often been the means of saving the lives of explorers and voy- 

 ageurs. The more important of these are GyropJiord proloscidea, 

 G. muhlenhergii, and G. veiled. Like all lichens, however, they con- 

 tain a bitter principle which may be partially removed by boiling 

 and soaking with alkalies, but even so, if eaten to any great extent 

 they cause serious intestinal disorders. 



It is hoped that the present paper will stimulate interest in this 

 remarkable group. In its preparation I have had the use of the 

 collections in the U. S. National Museum, and have also examined 

 several other collections abroad and in this country. The major 

 part of it, however, is based on the Bolander collection now in my 

 possession, the extensive collections of Dr. H. E. Hasse, and the 

 material collected in various parts of Europe and Western America 

 by myself. 



GYROPHORACEAE. 



The thallua is foliaceous, one to many-leaved, attached by a central umbilicus. 

 The underside may be naked and smooth or granular, or it may be more or less fibril- 

 lose or hirsute. An upper and an under cortex are present. The alga is Pleurococcus. 

 The whole development is markedly xerophytic. 



The apothecia are usually scattered over the upper surface, though in a few species 

 they are mostly marginal. They may be innate, sessile, or somewhat elevated, or 

 finally may be more or less proliferous. The proper margin is usually black, rarely 

 inclosing a few gonidia beneath. The disk is seldom smooth, but is generally gyrose- 

 plicate. The hypothecium is brownish to black. The asci have from 1 to 8 spores, 

 these colorless or dark, simple, septate, or muriform-multilocuiar. 



About 45 species are at present known in the three genera included in this family. 



KEY TO THE CALIFORNIA GENERA. 



Spores simple, small, 8 in number 1. Gyrophoea. 



Spores muriform-multilocuiar, 1 or 2 2. TJmbilicaria. 



1. GYROPHORA Ach. 



Gyrophora Ach. Meth. Lich. 100. 1803. 



Characters mostly as above. Asci with 8 spores, these colorless or becoming brown 

 with age, simple (plurilocular in a Peruvian species), ellipsoid or oblong, thin- 

 walled, without gelatinous halo; hypothecium brownish to black. 



The first species given by Acharius is Gyrophora glabra, first recognized by him as 

 Lichen glaber. a But earlier and later authors alike refuse to recognize this as a valid 

 species. Acharius gave polyphylla as a variety of glabra, but all later authors of im- 

 portance have reversed this and reckon glabra as a variety of polyphylla. One might, 

 therefore, be justified in calling polyphylla the type, but this isopen to the objection 

 that this species does not represent the genus as satisfactorily as some other species. 

 The first Linnsean species is Lichen velleus.b Some would therefore claim Gyrophora 

 velleus as the type of the genus, and it is as well entitled to such distinction as is glabra. 



« Ach. Vet. Akad. Nya. Handl. 15: 95. pi 2.f. 5. 1794, following Westr. op. cit. 

 14: 48. 1793. 

 &L. Sp. PI. 1150. 1753, following Dill. Hist. Muse. pi. 82. f. 5. 1741. 



