Scientlflf: Intelligence. — Botany. 193 



served, that an elm, situated in an insulated plantation, may be 

 felled with advantage when between seventy and eighty years of 

 age. 



III. Signs of Decay in a Tree. — When a tree becomes 

 crowned, i. e. when the upper branches die, it infallibly indi- 

 ' cates, especially for isolated trees, that the central wood is un- 

 dergoing alteration, and the tree passing to decay. When the 

 bark separates from the wood, or when it is divided by separa- 

 tions which pass across it, the tree is in a considerable state of 

 degradation. When the bark is loaded with moss, lichen, or 

 fungi, or is marked with black or red spots, these signs of alte- 

 ration in the bark justify suspicions of alterations in the wood 

 within. When sap is seen to flow from clefts in the bark, it is 

 a sign that the trees will soon die. As to wounds or gutterings, 

 these defects may arise from local causes, and are not necessa- 

 rily the result of old age. — Biblioth. Phys. Econom. 1826, 

 p. 13. 



22. Botanical Excursion in Sutherlandshire. — In an excur- 

 sion which Dr Graham took with part of his pupils into the 

 North of Scotland, in August last, the following stations for rare 

 Scotch plants were ascertained. 



Alisma ranunodoides^ ditch north end of Cromarty Frith. Radiola millegrana^ 

 abundant on road sides near Tain. Senecio liv'tdus^ abundant along with S. 

 sylvaticus^ on road sides near Lairg, Loch Shin. Senecio Jacobcea^ var. with- 

 out ray, abundant on sand-hills behind the manse of Farr, as well as in the 

 station at Strathy where it was observed by Dr Graham two years ago. 

 Schosnus nigricans^ very abundant on sides of Loch Shin, and many other 

 places in the west of Sutherlandshire. It is also extremely common in the 

 Isle of Skye. Carex panciflora^ bogs, side of Loch Shin ; Ben More, Assynt ; 

 and in several other stations in Sutherlandshire. Utrimlaria intermedia^ 

 bog on Ben More, Assynt ; small loch two miles east of Farr church. Apar- 

 gia alpina^ Ben More, Assynt ; as well as on Fonnivan, a mountain at the 

 toj) of Ijoch Inchard, in the same station in which Dr Graham observed it 

 two years ago. There is not a doubt that this is the plant known as A. al- 

 pina on the Continent, as has been proved by comparing it with authenti- 

 cated specimens from several stations on the Alps and Pyrenees ; but whe- 

 ther it be really specifically distinct from A. auiumnalis^ is a different ques- 

 tion. There seem to be intermediate varieties, and it is more than pro- 

 bable that this genus, and Leontodon in particular, are subdivided by the 

 Continental botanists beyond what is justifiable. In neither of the stations 

 mentioned is the plant abundant. Poa aipitia, and Hieraciiim alpinum, Ben 

 More, AsHynt ; neither of these plants were observed any where else in 

 Sutherlandshire. Droscra longifolia^ bog north side of Ben JNIore, Assynt, 

 far less common than D. anglica^ which is more abundant in the north and 

 west of Scotland than D. rotundifoUa. Cerastium alpinum^ Ben More, Assynt ; 

 and several other mountains in Sutherlandshire. Aira alpina, Ben More, 

 Assynt ; and Fonnivan, near the top. Cherleria sedoides^ on all the moun- 

 tains in Sutherlandshire, in the utmost profusion. Arbutus alpina, abun- 



OCTOBEE DECEMBER 1827. N 



