Mat. 1891.] BOTANICAL SOCIETY OF EDINBURGH. 



109 



No, 6. Abies Douglasii was only observed in 1888. It 

 was more irregular at first, but had a marked depression 

 from July 4 to August 16, ceasing to increase altogether in 

 the last fortnight of the period. Its subsequent rally was 

 comparatively feeble. 



Xo. 26. Finns Pinaster. The same remarks hold good 

 with regard to this tree, which, like the last, w^as inferior in 

 vigour to the others, having increased in girth only |- of an 

 inch, while they increased from 1^ to 1|^ inch annually. 



On the whole, it is evident that the remarkable mid- 

 summer halt was no mere accident of 1890, as it was equally 

 well marked in the same and in other pines in 1888 and 

 1889. The period of depression varied much, however, in 

 the diiferent trees, and even in the same trees in different 

 years, although possibly in some species it tends to be always 

 later than in others, — in Ahies Lowiana than in Ahies 

 (jrandis, for example. The following Table gives the approxi- 

 mate fortnightly period of the minima in illustration of 

 this : — 



Incidence of Summer Minima. 



B. Deciduous Group. 



1890. — The progress of girth-increase in the group of five 

 quick -growing deciduous trees does not show by any means the 

 same strong contrasts as in the pinaceous group ; at the same 

 time, in the former, as in the latter, there is no steady rise 

 and fall, with the maximum in midsummer, as might be ex- 

 pected. The weekly rise is pretty steady to the absolute 

 maximum of 635 in mid-June, but this is followed by a 

 gradual decrease to 385 in the beginning of July. In two 



