ADDITIONS TO THE HUSH MOSS FLORA. 237 



the most northern latitudes of our islands, where the normal erect 

 state seems to be wanting ; for here the plant seems to be unable 

 to grow except in tolerably deep water, and consequently always 

 assumes its floating state. 



Hybridity. — There is no doubt in my own mind that tbe different 

 species occasionally cross, tbough perhaps not so frequently as in 

 some other genera. The best instances have come before me in 

 Shetland, where 8. ajfine grows intermixed with the floating state 

 of S. simplex. The resulting hybrid differs from both of the parents 

 in being totally sterile, while in its more erect habit (thus 

 approaching the normal form of S. simplex, which does not occur in 

 Shetland), the greater vegetative activity, common in sterile hybrids, 

 is shown. The other characters are intermediate. I have received 

 from Dr. Neuman Swedish examples of this hybrid, as well as of 

 S. ramosum x simplex. In Britain I have seen examples which are 

 probably hybrids S. ramosum x neglectum and S. neylectum X simplex, 

 but concerning these further observation is necessary. 



The Stigma. — What has hitherto been called the " style" is in 

 reality a true beak of the fruit. The stigma is sessile, or it may be 

 regarded as a style which is stigmatic on one surface throughout 

 its whole length. It is obliquely decurrent on the beak for a very 

 short distance. In dried specimens the difference is not perceptible, 

 but in fresh fruits the beak is seen to be of the same colour and 

 herbaceous texture as the rest of the fruit, and its junction with the 

 hyaline stigma, obliquely sessile on its apex, is easily seen. 



Fertilisation. — Dr. Focke has well remarked* that the Spargania 

 are eminently proterogynous. So far as I have observed, they are 

 chiefly wind- fertilised ; while in the floating species the pollen is 

 doubtless sometimes carried to other plants on the surface of the 

 water. Neither the erect nor the floating forms appear to be visited 

 by insects except by rare accident. 



The subject of hybridity in this genus seems to afford con- 

 siderable opportunity for further research, but continued out-door 

 observations are necessary ; and a ground-work of knowledge, 

 founded on the study of the plants as they grow, is an essential 

 preliminary to the comprehension of the often illusory characters 

 presented by dried specimens whether of the hybrids or the species 

 themselves. Unfortunately the preliminary is too often neglected, 

 not alone in this genus, and the resulting consequences cannot fail 

 often to appear grotesque, at least to those who know something of 

 the plants themselves and not their reputed measurements merely. 



ADDITIONS TO THE IRISH MOSS FLORA. 



By David McArdle. 



In the April number of the ' Revue Bryologique,' there is an 

 interesting note on Hypnum circinale Hook, by M. J. Cardot, an 

 eminent French botanist, who detected it amongst some mosses 



anil. Naturwiss. Ver. ■/,. Bremen, v. p. 409 



