ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 475 



of air-chambers, which, as in Dumortiera, may be due to degeneration. 

 From Dumortiera it is distinguished by a series of characters. 3. The 

 reproductive organs are situated on receptacles, which place the genus in 

 the group Composite. Antheridial and archegonial receptacles are 

 formed in succession. The antheridial receptacles are thrust aside on 

 to the upper side of the thallus by the early formation of the ventral 

 shoot ; and the same may happen to the female receptacle. 4. In the 

 sporogonia the formation of elaters is so reduced that the chlorophyll- 

 containing "elaters" are comparable with the nutrition-cells (Nahrzellen) 

 of Corsinia, Sphserocarpus, and Riella. 5. The forms of the Riccia- 

 Marchantiaceas series which possess dorsal receptacles (Stande), or dorsal 

 antheridia and archegonia not grouped into receptacles, are not, as has 

 been accepted since Leitgeb's time, primitive, but are reduced. This 

 most probably applies to the sporogonia of Riccia, which has carried the 

 reduction (begun in Monoselenium, Corsinia, Sphserocarpus, and Riella) 

 to such a pitch that the elaters have been completely suppressed. The 

 male receptacles disappeared sooner than the female, losing the independ- 

 ence which in many forms the female partially retain. 6. " Andro- 

 gynous " receptacles were found not only in Monoselenium in different 

 states of development, but also in Corsinia. The division of the sexes 

 in Marchantiacese is therefore a fairly labile one, as is shown by the 

 much better known examples of Preissia, Dumortiera, etc. 



Dendroceros.* — F. Stephani gives an account of the genus Dendro- 

 ceros. He describes the morphology. The vegetative thallus is of a 

 simple character ; but the sporogonium is highly developed and brings 

 the genus near to the true Mosses. Stephani thinks that Dendroceros is 

 reduced from some leaf -bearing ancestor, the stem being reduced to a 

 midrib and the leaves to the wing-like laminaa. The length of the 

 sporogonium in a given species depends on the size of the thallus. 

 Satisfactory characters for the discrimination of species are found in the 

 stoutness of the midrib, and in the size and form of the external sporo- 

 gonial cells. Stephani describes twenty-three species. 



Scotch Bryophyta.f — J. A. Wheldon and A. Wilson publish a list 

 of Cryptogams collected amongst the Cairngorm Mountains in Inverness 

 and Banff in July 11)09, and mostly additional to the list of specimens 

 collected in the same district in 1908. They enumerate sixteen Sphagna, 

 sixty-six mosses, thirty hepatics. 



New Records of British Sphagna 4 — E. Armitage publishes some 

 new county records of Sphagna determined by J. A. Wheldon and 

 W. Ingham. They were gathered in Elgin, Easterness, Berkshire, 

 Radnor, Westmorland. 



North American Bryophytes.§ — C. C. Haynes gives a description 

 and figures of the rare hepatic Pleuroclada albescens Spruce, an Alpine 

 species of North Europe and Greenland, which is now recorded from two 

 localities in the Rocky Mountains of the United States. 



* SB. Natur. Gesell. Leipzig, xxxv. (1908) pp. 11-21. See also Bot. Zeit., 

 lxviii. (1910) p. 114. 



t Journ. Bot., xlviii. (1910) pp. 123-29. t Tom. cit., p. 163. 



§ Bryologist, xiii. (1910) pp. 49-50 (pi.). 



