269 



Middle ob- 

 struction. 

 Stoppage of 

 the ijitli. 



ON THE INTEllIOR OF PLANts. 



I have seldom seen this vary ; nay, even in compound 

 flowers of the 8ynq;enesian order, where the divisions are so 

 often repealed, and the compartments of each perfect flower 

 so very minute, the pin-holes of the stamen surround the 

 larger apertures of the pistil, and, accompanied by the 

 vessels appropriated to each petal, are as exact and as ex- 

 actly delineated as below the lar;^est flower, a campanula, 

 or a lilly. Let any person see a vegetable cutting of the 

 peduncle of a syngenesiaji superflua in a solar microscope, 

 and he will have no doubts. This is made still plainer by 

 the bursting of the vessels of a double flower, and the con- 

 fusion that ensues, one part growing for another, one on 

 another ; sometimes the wood escapes bursting, and then 

 the males are periVc* ; sometimes the line of life does its 

 office till it passes a second time into the pericarp, in the 

 way to the seeds, and then fails; and in this case all is per- 

 fect but the seeds, which do not vegetate. In my opinion, 

 it would be a much greater wonder to suppose such different 

 parts to be formed of the same matter, than to conceive that 

 each had its appropriate juices. But I mean not this as an 

 argument. I never allow myself to reason in this manner. 

 1 rely on experiment, observation, and dissection only, and 

 1 may say, without vanity, on a labour, few would submit 

 to ; and none can appreciate but those who know me. 



Having described the grand obstruction, I shall now' show 

 the middle one. This is formed by the stoppage of the pith. 

 1 he pith is most properly esteemed a source of moisture to 

 the tree ; but when I come to show the manner of passing 

 of the buds, I shall prove a still more direct use for its 

 moisture. The pith stops in all trees at every new branch, 

 forming a piece of wood, which generally fills up nearly 

 half an inch, apparently to give the plant, by a great acces- 

 sion, strength sufficient to invigorate and produce healthy 

 branches. The ])ith therefore recoils, not only in the new 

 bud, but in the main stem also. But in smaller plants the 

 new shoot alone generates new wood, which appears an ac- 

 cession sufficient for such slender twigs ; where the pith oc- 

 cupies so large a portion of the plant: and in some annu^fls 

 and herbaceous yjlants the pith stops not at all, but is con- 

 tented with drav»ing the hue of the corners of the w6od 



closer ; 



