1 46 Societas pro Fauna et Flora Fennica in Helsingfors. 



confined to the lower epidermis, but a few occur, toward the base 

 of each leaflet, near and parallel to, the veins on the upper sur- 

 face. In the latter, stomata are most abundant on the lower 

 epidermis, but are uniformly and pretty closely disposed over 

 the upper. 



On bright hot days, when the leaflets were paraheliotropic, 

 numerous examples were studied in the fresh state and after fixing 

 in alcohol, chromic acid, etc. The fresh specimens consisted of 

 epidermis stripped and arranged under the microscope within a 

 minute after the leaves had been removed from the plant, this 

 work having been largely conducted in the field. In every instance, 

 the stomata of the lower epidermis were either considerably or 

 widely open. On the upper epidermis none were met with quite 

 closed, but according to the degree of paraheliotropism the stomata 

 ranged from wide open to three-fourths closed. The same prin- 

 ciple applies to Strophostyles angulosa which has its stomata uni- 

 formly distributed over upper and lower epidermis, but in the 

 proportion of one above to three below. 



No continuous record was kept of the movements of the leaf 

 stalks in the species studied, but such are regulär and considerable 

 in amount both in transverse and horizontal direction While the 

 vertical motions are probably largely due to differences in tissue 

 tension, the lateral ones seem to be determined by illumination, for 

 their movements are such as to permil, the leaflets to place them- 

 selves in a diaheliotropic relation when expanded. 



(Fortsetzung folgt.) 



Originalberichte gelehrter Gesellschaften. 



Societas pro Fauna et FSora Fennica in Helsingfors. 



Sitzung am 6. April 1889. 



Herr John Linden sprach : 



Ueber seine 1888 in Süd-Carelien vorge- 

 nommene Reise. 



Das Gebiet, welches sich zwischen 60° 43' und 61° 13' N. Br. 

 3° 50 und 5° o. L. (Helsingfors) erstreckt, zerfällt in zwei in 

 botanischer Hinsicht wesentlich verschiedene Theile : in das an 

 Pflanzen reichere, durch viele Linden charakterisirte „Vuoksen- 

 Gebiet", von der Krümmung des Flusses nach Osten bis zu dessen 

 Mündung im Ladoga, und in das innere, durch eine verhältniss- 

 mässig dürftige Vegetation ausgezeichnete, an das südliche Savo- 

 laks und Ladoga-Carelien grenzende Gebiet. 



Die Artenzahl der im Gebiete beobachteten Gefässpnanzen 

 beträgt 528, von denen 250 allgemein, 118 hier und da zer- 

 streut und 160 selten sind oder eine unsichere Verbreitung 

 haben. Von diesen verdienen Epipogon aphyllus, Cirsium hetero- 

 phyllum X palustre und Calamagrostis Hartmaniana hervorgehoben 



