552 
VII. LICHENE8. 
vate, transparent, jointed bodies, whose terminal cells are thiek-walled, are often crustaceous, 
warted, coloured, and adhering together from the hard surface of the thalamium. The asci 
are shorter vertical bodies, linear clavate or ellipsoid, tapering downwards, and consist of 
simple, thick-walled, transparent sacs, containing one or more, usually 8, very minute spores. 
At maturity the ascus breaks at the top, discharges the spores, and shrivels up, when fresh 
asci are developed from the hypothecium, and this process goes on as long as the apothecium, 
which is perennial, exists. 
The spores are usually ellipsoid, but may be of any shape, and are simple or internally 1- 
or many-septate, or divided both transversely and longitudinally into sporidia. 
The spermagones are microscopic, simple or compound cavities in the thallus, opening by 
pores, whose orifice is usually dark ; they are full of gelatine, and contain sterigmata, 
which are simple or branched, articulate or inarticulate filaments ; short, straight, articulate 
sterigmata are called arihrosterigmata. Upon the sides or tips of the sterigmata are the 
spermatia, which are most minute, ovoid, ellipsoid, linear or acicular, straight or curved, 
colourless bodies. The spermatia accumulate in the cavity of the spermagone and escape by 
its pore ; they appear to be the analogues of the antherozoids of Algae, etc., but have no 
cilia, and are not developed in antheridia. They are found in maturity usually in spring or 
summer, long before the spores of the apothecium are mature, aud the relations between these 
two kinds of organ is unknown. 
Pgand.es are larger, thicker-walled, sometimes superficial spermagones, of which the ste- 
rigmata are simple, inarticulate, tubular, tapering pedicels, called stylospores, that bear at 
their tips bodies analogous to spermatia, but larger and curved oblong and full of granular 
contents. 
In germination the sporidia of a Lichen give off one or more branching filaments, whose 
branches interlace and form a network, the hypothallns, which again develops into the me- 
dullary stratum. A layer of colourless cells next spreads over the hypothallus, and amongst 
these the gonidia appear. In many Lichens, including most of the corticolous ones, there 
is no further development of thallus, the apotheeia growing from this, aud in some few 
the hypothallus aloue is formed. In the higher forms however a cortical layer is added. 
The hypothallns, though often evanescent, is present as the fibrils of Sticta, the black 
fringe of I.ecidea geographica ; and in other forms or colours, in many other corticolous and 
rnpicolous species. 
The food of Lichens is not confined to the gaseous elements, for they take up mineral 
matter in abundance, especially carbonate aud oxalate of lime, besides compounds of alumina, 
silica, iron, potash, soda, magnesia, aud even of metals, as manganese and iron. Some species 
attain a great age, and some appear to burrow into the rock they inhabit ; this burrowing 
has been attributed to a corroding power in the vegetable, but I should think it rather due 
to the action of the moisture they retain around them. 
The study of Lichens is in every respect a most difficult one ; the great master of the sub- 
ject is Dr. Nylander, whose arrangement I have followed here, and would refer the student 
to his worlds for details I am unable here to give ; these are, especially, his ‘ Synopsis Li- 
chenum,’ ‘ Enumeration Generale des Lichens,’ and ‘ Expositio Pyrenocarpeorum.’ 
Of British authors, Dr. Lauder Lindsay’s ‘ Popular History of British Lichens ’ (12mo, 
with 22 plates) is a very good work, being very lucidly written and illustrated by capital 
figures. 
The New Zealand Lichens were first hastily named aud published by Dr. Taylor ; since his 
death, my friend the Rev. C. Babington, a learned man and most sagacious Licheuist, worked 
them up with great care aud skill for the 1 New Zealand Flora ;’ and, more recently. Dr. 
Nylander has reviewed the majority of them, and verified most of Mr. Babiugton’s determi- 
nations. A considerable number of species are introduced from a manuscript, kindly lent me by 
Dr. Lindsay, which contains the botanical results of his visit to the islands. Lastly, many 
additions are due to Dr. Knight’s skilful researches amongst the corticolous genera, the re- 
sults of which, by Mr. Mitten and Dr. Knight, are published in the Linnean Society’s Trans- 
actions, illustrated by microscopic drawings of great beauty, made by Dr. Knight. 
The following pretends to no more than a sketch of New Zealand Lichenology, and I ex- 
pect that fully as many species remain to be discovered as are now known to exist in the 
islands. Since the following descriptions were v : ritten. Dr. Lauder Lindsay has communicated 
to the Botanical Society of Edinburgh, a list of Lichens found by himself at Otago, in which 
