OF FILAMENTOUS, FRUTICULOSE, AND FOLIACEOUS LICHENS. 121 
times they retain their sterigmata as caudate appendages, shrivelled, but still dis- 
tinct. Their colour is sometimes a pale yellow. 
Size, like form, is variable. The length varies from jth to zath of an inch, 
and the breadth from th to aath. Their size is therefore much greater in every 
dimension than that of the spermatia. At the same time, they are much fewer 
in number than the spermatia. 
They are given off from the apices only of the sterigmata, and they are said 
by Nyzanper to possess the power of germinating. 
Function of the Pycnides and Stylospores.—Founding solely or chiefly on their 
alleged power of germination, the stylospores are described in the latest conti- 
nental work on lichens (NYLANDER’s “ Synopsis”) as sporotd bodies, that is, 
resembling spores, both in form and function. According to this view, we should ° 
regard the pycnides as secondary or supplementary apothecia. I have not, how- 
ever, seen this germination of the stylospores for myself; neither have I observed 
impregnation of the spores by the spermatia; and though I am inclined, so far 
as my own observations have gone, to the views regarding the functions of the 
spermogones and spermatia, pycnides and stylospores,—which I have above 
enunciated as those taken by continental observers,—all that I feel warranted 
at present in advancing is, that I believe both spermogones and pycnides, in some 
way not yet fully established, to subserve the purposes of reproduction in lichens. 
FAMILY I. Usnez. 
GENUS I. Usnga, Hof'm. 
The spermogones of this genus are extremely difficult of discovery, from their 
being of the same colour as the thallus, and from the ostiole being pale and incon- 
spicuous; moreover, they are seldom met with. Ihave examined hundreds of speci- 
‘mens in every state, and from all manner of habitats, without success, and I had 
despaired of ever finding its spermogones, when, about two years ago, I suc- 
ceeded in discovering them in abundance in a specimen of U. barbata, var. hiria, Fr., 
in Lercuton’s “ Lichenes Britannici exsiccati.” I have subsequently found them 
more plentifully in foreign specimens of the same species. J am now in a position 
to announce that the variety hirta of the older authors is, in great part at least, 
simply a spermogoniferous state or condition. It is partly also a state in which 
sorediiferous, instead of spermogonal, warts are abundant. These two separate 
kinds of warts can seldom be safely distinguished otherwise than by microscopical 
examination. I am not aware that, at the period of my discovering the spermo- 
gones of Usnea, I had been anticipated in my observations by any previous author. , 
KoERBER says distinctly, “ Spermogonien sind bis jetzt weder an dieser noch den 
andern arten aufgefunden worden.’’* Since the date of my original observations, 
* « Systema Lichenum Germanie,” “ Die Flechten Deutschlands,” von Dr G. W. Kogrrzer. 
Breslau, 1855. P. 3. (Sub U. florida, L.) 
VOL. XXII. PART I. Di 
