McArdle — On the Hepaticce of the Hill of Howth. 109 



In the summer of 1891, I was on an excursion of the Dublin 

 IS'aturalists' Field Club to the Hill of Howth. The weather was 

 unfavourable for collecting, and we only succeeded in gathering a few 

 Liverworts, and when examining them afterwards, under a dissecting 

 microscope, I picked out a few stems of CejjJialozia francisci, imperfect 

 specimens, mixed with the common Cephalozia bicuspidata, but suffi- 

 cient for identification, so distinct is this rare plant. Encouraged by 

 this find, I availed myself of the further opportunities to visit the 

 hill, and to endeavour to rediscover the plant. This I succeeded in 

 doing, and I found a small quantity, fortunately, in fruit, which I 

 sent to Dr. Spruce, the acknowledged authority -on such matters, and 

 his interesting communication concerning the plant is as follows : — 

 *' Many thanks for Cephalo%ia francisci, which is indeed the true plant, 

 and in good fruit ; as you say, it is probably new to Ireland, for 

 when I visited Dr. Taylor at Dunkerron, all he had under the name 

 of Jungermania francisci were merely varieties of Cephalo%ia divari- 

 cata. It is doubtful if Miss Hutchins' plant was anything more." 

 " Collected near Bantry, Miss Hutchins, very rare in Ireland." This 

 was the only locality quoted by the late Dr. Moore in his excellent 

 work on the Irish Liverworts. Since the period referred to, I have 

 visited the Hill of Howth many times in search of these plants, and 

 I have become well acquainted with the habitat of this rare species, 

 and have observed its growth. It is very scarce, and only grows in 

 one place, on a small shallow bog near Ballykil plantation, on lower 

 Carboniferous limestone which belts the hill, round to the village 

 of Sutton. In the same locality I also found the rare Cephalozia 

 denudata (more widely known as Odontoschisma denudata) ; Dr. 

 Spruce remarksi that Cephalozia francisci is almost a miniature copy 

 of this, having the numerous flagellae, the sub-orbicular leaves, the 

 female involucre and perianth, the reddish gemmae borne on the apex 

 of attenuated branches, &c. The only slight but distract and constant 

 apical notch of the leaves of Cephalozia francisci is quite wanting in 

 Cephalozia denudata. It was the copious gemmse which were quite 

 perceptible from a little distance, and gave the black peat on which 

 the plant was growing a golden colour, that first attracted my atten- 

 tion to it ; and I had no difficulty in at once determining it from the more 

 common Cephalozia sphagni of our bogs, by the help of Hooker's 

 unrivalled Monograph of British Jungermaniae, where it is figured 

 under the name of Jungermania sphagni (Supplement, table n.), and 



1 Spruce on Cephalozia, p. 9. 



