102 
CALIFORNIAN FUNGI. 
Glaeosporium carpigenum. Cite. 
Innatum, sparsum, cuticula tectum, demum perforatum. Sporis 
elongato-ellipticis, hyalinis, *013-*018 x '0035 mm., in cirrhis albi- 
dis exudentibus. 
On fruit of JEsculus californica. Sierra Nevada. No. 1066. 
Colaeosporium Madise. Cite. 
Laete aurantium. Soris epiphyllis, ovatis, erumpentibus. Sporis 
concatenatis, aurantiacis, globoso-compressis, laeve, -023 X '018 mm. 
On living leaves of Madia Nuttallii. Sierra Nevada. 
Cytispora salicis. Rabh. 
On willow twigs. Sierra Nevada. No 1023. 
Not a good Cytispora , probably better referred to Phoma. 
To the above may be added the following species from New 
York:— 
Stereum scriblitum. B. 8f Cke. 
Coriaceum, pileo effuso reflexoque, rugoso-striato, obscure con- 
centrico zonato, fuligineo-nigrescente ; bymenio nudo, glabro, 
pallido subcinereo, demum rimoso. 
On branches. New York, Gerard (171). 
A very distinct species, externally nearly black and faintly zoned 
and striate ; the hymenium pallid, with a cinereous tinge, soon 
cracked. Whole substance brittle when dry, curling inwards. 
THE DUAL-LICHEN HYPOTHESIS. 
“ That hypothesis which is based on sound scientific knowledge is sure to 
have a corresponding value, and that which is a mere hasty random guess 
is likely to have but little value.” — Prof. Suxley , Lectures (1863), p. 67. 
Truth has often been discovered by the aid of a hypothesis, 
hence the proposition of a hypothesis for the advancement of science 
is perfectly legitimate. Some hypotheses which have been pro- 
posed in the past have proved utterly untenable when they have 
been assailed, therefore before any hypothesis is accepted it should 
be subjected to all possible tests. Any hypothesis which cannot 
suffer criticism is not worthy of acceptation. The dual-lichen hypo- 
thesis is worth very little if unable to meet all the objections 
which such an assailant as the present can urge against it. 
Without contenting myself with reviewing the remarks of single 
individuals, I will rather go direct to the main source of the theory 
of which Schwendener is the author. In a few brief sentences the 
whole gist of the hypothesis may be summarized. Although at 
first only the group called the Collemacece were included, ulti- 
mately as his views extended, he included all Lichens in the cate- 
gory of Algo-fungi. These are his words, “ As the result of my 
researches all these growths (Lichens) are not simple plants, not 
