AND LIFE-HISTORY OF A TROPICAL EPIPHYLLOUS LICHEN. 115 
so, we may proceed to inquire into the position of the Lichen from the point of view of 
the systematist. 
The structure of the “ thallus,” and the relative positions of the main masses of the 
Fungal and Algal portions, agree with what occurs in heteromerous crustaceous Lichens, 
such as Ше Стар ею; but the perithecia indicate an Angiocarpous alliance, bringing 
this form nearer such families as Pertusarie and Verrucarie, to the latter of which 
it may ultimately be referred. 
A few remarks may be pertinently introduced here as to the possible light now thrown 
on such aberrant forms as * Strigula,” “ Cephaleurus," &c.* I һауе not been able to 
examine original drawings or preparations of these forms; but every thing points to the 
probability that the old genus “ Strigula”’ includes the “Lichen” I have described, 
while the form ©“ Cephaleurus” (which has been associated, I believe, with Sérigula) is 
simply the Alga studded with its barren and * fertile " hairs (Pl. XIX. figs. 15 & 10). 
At figs. 80 & 81 of the Rev. M. J. Berkeley’s * Introduction to Cryptogamie Botany’ are 
some drawings which may throw unexpected light on this question. Тһе asci and spores 
figured are suggestive of those shown in my РІ. XXI. figs. 66 & 681; and the small 
sketch of а thallus and perithecium bear out this view, which becomes rendered sufti- 
. eiently evident by Berkeley's fig. 81 to admit of our acceptance that the Lichen which 
I have described is a species of ** Strigula,” of the old group Limborei, probably a section 
of Verrucarie |. Іп conclusion, I would earnestly recommend an exact study of some 
of the points raised above to those botanists who have opportunities in the tropics. The 
whole group of * Epiphyllous Lichens" would no doubt well repay prolonged and 
careful investigations. 
DESCRIPTION OF THE PLATES. 
Puate XVIII. 
Fig. 1. Shoot and leaves of Michelia fuscata, on which the epiphyllous Lichen is seen in all stages of 
development. The orange-red patches consist of the Alga alone. The green and grey patches, 
with small black dots in them, are early stages of the Lichen. Their colour varies according to 
the predominance of the hyphe or the Algal thallus. The complete Lichen is represented by the 
white porcellaneous patches. All natural size. 
Fig. 2. Four of the orange-red patches removed from the leaf, and showing the general external 
characters of the Alga: a, nat. size, and much branched; б, similar thallus examined with a 
simple lens, and showing the crowds of “ fertile hairs ;” c, portion of a thallus more magnified 
(Gundl. 1, ос. 2), and studded with “ barren hairs." The specimen с was not so finely 
branched as the others. All transitions between these types and rounded forms exist side 
by side. 
* See Berkeley, Introd. to Crypt. Bot. 1857, p. 390. 
+ In Mr. Berkeley's sketch are three and four spores respectively in the two asci; possibly no account was taken 
of the numbers. 
+ Vide Luerssen, Med. Pharm. Bot. i. p. 212. 
