72 



male flowers of the plant itself or of others related to it, and the fact of the stigma 

 remaining so long unchanged, and not exhibiting the symptoms usually seen in stig- 

 mas after having been acted upon by pollen, I can arrive, — especially after the length 

 of time during which I have watched it, — at no other conclusion than that pollen is 

 not essential to the perfecting its seeds ; but if an external agent be necessary, and 

 really act upon the stigma, I am unable to say what that agent is or how it acts. I 

 might mention a view which I at one time entertained, namely, that the viscid fluid 

 which issues from the glands situated below the ovarium might produce some efi"ect 

 by exciting the action of the pistillum ; and this view received some support from find- 

 ing the ydung stigma often smeared with the fluid. That there is some specific action 

 on the ovula I think there can be no doubt ; for, as in most other plants, some of the 

 ovula are frequently abortive. 



" My object being merely to state the facts observed respecting this plant, without 

 the intention of advancing any opinion on the various theories of vegetable impregna- 

 tion, I shall conclude by merely observing, that the absence of pollen in this instance 

 is irreconcil cable with the theory that every grain of pollen furnishes a germ, and that 

 the ovulum is merely a matrix to receive and nourish it till it becomes a perfect seed." 



(To be continued). 



Art. XXVITI. — Notice qf^A History of British Forest Trees, Indi- 

 genous mid IntrodAiced^ By Prideaux John Selby, F.L.S., 

 M.W.S., &c. London : John Van Voorst. Parts 2 and 3. Au- 

 gust and September, 1841. 



The second part of this elegant work contains portraits and descrip- 

 tions of four trees ; — the wild cherry, the whitethorn, the mountain 

 ash and the common ash. Mr. Selby considers the cherry well worth 

 cultivating as an ornamental tree, principally on account of the pro- 

 fusion of its flowers at an early period of the year, and the rich purple 

 tints of its foliage in the autumn. The whitethorn, or quickset as we 

 term it, is more apt to be regarded as the staple commodity of our trim 

 English hedges than as a forest tree ; still, Mr. Selby has selected so 

 noble a specimen as an illustration of the species, that it reminds us 

 of a figure we have somewhere seen of the gigantic * chestnut of a hun- 

 dred horse ' long celebrated by travellers. The rowan, that familiar 

 tree, is represented more in accordance with our ideas of its magni- 

 tude. 



" The mountain ash grows in almost every district of Britain, but its favourite ha- 

 bitats and where it reaches its greatest size and most imposing appearance, are moun- 

 tainous declivities, or in those deep dells in mountainous and hilly districts, where 

 the earth is loose and free, and kept in that moist state most congenial to its growth, 

 by the percolation of the rain and dews, or of springs which issue from the disruptured 

 rocks. In such localities it frequently becomes a tree of the second or third magni- 



