REVUE BRYOLOGIQUE 
paternum forma gracilis. The long, narrow-pointed leaves of the 
 latter had changed into the short broad flat pointed leaves of the 
_ former, and, as the illumination was now equal on the whole 
plant, there was copious branching with the var intermedium 
(forma penna). 
At one side of the pool is a little clay and ground supporting 
H. aduncum forma falcata of two colours green and brown in 
separate tufts, and on the margin of the clay and shaded by short 
grass is the var. diversifolium mixed with Æyp. cuspidalum. These 
are no doubt stranded derivatives of the submerged Æ. aduncum 
var. paternum forma gracilis. | 
Thave found forma falcata in several places, as by the wet 
_ sandy sides of paths, but always in places with frequent changes 
from dryness to wetness, and never submerged. 
II. HyPp. FLUITANS. 
In a large pool on Skipwith Common, 40 mis. from York float 
large, entangled masses of Æyp. fluitans, var. gracile, forma 
longifolia, with remarkably long whip-like acumen. This moss 
slowly drifts to the side, and on 19 July 1898, after much search- 
ing, 1 found a little fruit. The seta is very long, one measuring 
4 7/8 inches with an absurdly small capsule, about the size of 
that of Eurhynchium confertum, and of the same shape. The 
moss is copiously branched, due to the floating. ; 
On 41 Oct. 1901 I found masses of a vivid green moss embed- 
ded in mud at the side of the pool, and there is little doubt that it. 
originated from the floating gracile by becoming stranded in the 
mud. This is the var. atlanticum, which, as regards N. England, 
is equally at home on the East side as on the W. side. The small 
channels running from this pool are filled with the var. Arnellii, 
growing in extensive masses in shallow water. On 12 Sept. 1901 
I found two ripe capsules of this var; and many stems with 
copious male flowers, arranged along almost the whole length of 
the stem like a row of beads. I gather from the above material 
that the var. Arnellii is dioicous. This may be of interest, as du 
Mons Renauld in the Muse. Gall. says ‘« Sexualité inconnue ». 
bed of it was of the var. Arnellüi. The next pool was entirely of 
the var. Jeanbernati, approaching the var. elatum. T cannot at 
present suggest the origin of var. Arnelli and of var. Jeanbernati. 
The Group Aotæ forms quite a feature of the Plain of York, | 
forming the bed as it were of several shallow pools and often 
mixed with Sphagnum. In a deep pool on Strensall Common is 
very fine Rolæ with all its characters well-developed. 
Tracing one of these channels I found another pool and the whole  ; 
où» 
