Notes. 
129 
stomata of cotyledons do not seem to vary much on the under surface ; 
but on the upper surface there is greater difference. Water-pores, 
when present, are usually found on the upper epidermis over the 
epithem, which is formed at the end of the median vein. When 
w r ater-pores are present there are few or no stomata on the upper 
epidermis, when absent there are many stomata. 
This would lead one to suppose that a group of a few water-pores 
at the apex of a cotyledon is equivalent to many scattered stomata 
which appear over the upper epidermis in the absence of water-pores ; 
but no weight can be attached to this until the subject has been more 
fully investigated. 
ROBERT TURNBULL, Edinburgh. 
A DISCOVERY IN CONNECTION WITH THE PRO- 
DUCTION OF HYBRID FERNS.— Occasionally in a batch of 
seedling ferns there will occur several plants of some strange marked 
variety identical in their characters, and I have long suspected that 
these were produced on one and the same prothallus ; indeed this 
seemed evident in four instances of remarkable seedling Athyriums, 
yet the development was too far advanced to enable me to be 
absolutely certain. However, in order to prove this a number of 
Scolopendriums were planted in the prothallus state, and on the young 
fronds appearing a few days ago, two separate fronds were noticed 
identical in character and unusual in form, which, when examined 
by the aid of a magnifying glass, were found to have their origin in 
one well-developed prothallus. With a penknife it was possible to 
divide the prothallus so as to secure two plants, and this w r as not the 
only instance observed. Next season’s growth will prove whether 
these plants will retain their likeness to each other. 
E. J. LOWE, Shirenewton Hall. 
FURTHER NOTE ON SPONGOCLADIA.— With reference 
to our paper on Spongocladia in Annals of Botany, Vol. II, p. 169, 
we wish to make public a suggestion, kindly made by Dr. Hauck in a 
letter, that the supposed symbiotic relationship between sponge and 
K 
