LEJEUNEA HOLTII, A NEW HEPATIC FROM KILLARNEY.. 77 
of ore (not tropical) type. It would be interesting to watch, year 
by year, the peopling of such quarries with plants of all orders ; to 
ans ae origin of the first colonists, and of later arrivals to 
fraternise with or displace them. Some of our Yorkshire quarries, 
having lain undisturbed for a century or more, have become not 
only shady groves, but veritable moss gardens. om oe ae 
prefer to grow upon mosses, it is rather an advan o them 
find the ground already sree bc the latter, whieh Pode aie 
any harm from their quasi-par 
When we come to tian he case of certain hepatics phere 
so far as we know, seem doomed to perpetual sterility, yet h 
spread far and wide, it is no longer a question of the disp bet of 
spores by any possible agency. Hepatics may be propagated, pei 
only by spores, but (1) by gemme, of various forms, produc 
the margin s or perianths; (2) by sali weigss 
minutely-leafy branchlets springing from ae cell on the surface 
0 leaf, mo stem or perianth.* Both these modes 
a new plant, and in this way I have seen various Plagbehile B apse 
gated without fruiting. It is perhaps more frequent i in mosses than 
in hepatics. Hardly any moss is more forme in the Pyradioal 
than the large and handsome Fissidens grandifrons, yet only the 
although never fruiting. Some mosses whose fruit is a great rarity 
are widely propagated by axillary bulbils, like Brywm —— or 
by fascicles of deciduous branchlets, as in Plagiothecium Borrerianum. 
jeunea ovata and L. ulicina we have ouly the sterile le fomalo 
Yet, alihongh nowhen e common, late investigations have shown 
oth s o have ide range on and near ote ibe: teen, 
which has transported t ily, or portions . — a of 
developing into perfect ink to. where they ar w flouris 
Metzgeria pubescens is a far more g instance af ak distri ‘bution 
of a species, which to this day is known only in barren state, 
although very common in hilly districts ghroughoat not. only 
'__*In the ‘Phytologist’ for March, 1845, I described and figured, from 
Killarney ‘eockeasenactoe cell-suckers of Jungermannia adunca Dicks. Cf. also 
the introduction to the genus Plagiochila in + Hagan Am. et And.’ 
