862 REPORT— 1897, 



means by which they resist the drying of their tissues. The facts cited are held 

 by him to indicate that respiration is ihe normal function of stomata, and that the 

 loss of water through stomata is incidental and secondary. The author concludes :— 

 1. That one of the functions of stomata is the admission of carbon dioxide to 

 the chlorophyll-bearing tissues of the plant for use in the formation of the carbo- 

 hydrates. 2. That the loss of water by terrestrial plants was originally hurtful, 

 and is so now in many cases. 3. That if plants have utilised this constant phe- 

 nomenon, it is for the supply of food matters of secondary importance, as the salts 

 in solution in the water of the soil. He cites observations and experiments to 

 corroborate his views. Thus Stahl and Blackman have shown that carbon di-oxide 

 enters through the stomata ; Stahl has shown, also, that transpiration takes place 

 through the stomata, but many observations show that stomata quickly close when 

 the water supply is deficient. Stahl, again, has shown that the leaves of ever- 

 greens have their stomata closed during the times when no carbon assimilation can 

 take place (that is, in winter) ; observations show that green parasites (mistletoe, 

 &c.) have many stomata, while those not green (dodders, &c.) have scarcely any. 



FRIDAY, AUGUST 20. 

 The President's Address was delivered. See p. 8.31. 



The following Papers were read : — 



1. On the Species of Picea occurring in North-eastern United States and 

 Canada. By Professor D. P. Penhallow. 



Since the time of Pursh the validity of the red spruce as a distinct species has 

 been generally denied by systematic botanists. In 1887 the late Dr. George 

 Lawson maintained, in a paper before the Royal Society of Canada, that the red 

 and black spruces are distinct species. This view has been sustained during the 

 past 3'ear by Britton in his ' Illustrated Flora of North America.' My own studies 

 prosecuted during the past two years have likewise shown that there are abundant 

 reasons for the separation of P. rubra as a distinct species. 



Incidentally attention has been directed to a form of the white spruce 

 characterised by its foetid odour and its strongly glaucous, rigid, and often 

 cuspidate leaves, which are commonly produced at the base. For this the name 

 fcntida is suggested. 



2. Contribution to the Life History of Ranunculus, 

 By Professor Coulter. 



3. On the Distribution of the Native Trees of Nebraska. 

 By Professor Charles E. Eessey. 



The State of Nebraska occupies a central position in that portion of the North 

 American continent where forest trees may grow. In this great area it lies almost 

 centrally again within the prairie region, which extends from the Mississippi 

 River to the Rocky Mountains, and stretches from Saskatchewan to Texas, 

 Beginning with an elevation of a little less than 300 metres along the Missouri 

 River, which forms its eastern boundary, it rises gradually to an altitude of about 

 1,700 metres near its western border. From east to west it is an undulating plain 

 whose western edge has been much uplifted. Down this slope run the Niobrara, 

 the Platte, and the Republican Rivers, each a turbid mountain torrent rushing 

 swiftly and directly from the Rocky Mountains or the foot-hills to the Missouri 

 River. 



