SHOUT ON WESTERN BOTANV. 



97 



not suffice to explain any effect which is so very general. If 

 my opinion upon the true origin of the evil be contrary to 

 that of more experienced Horticulturists, I shall be only too 

 happy to accept any more rational explanation of the facts 

 described in the foregoing pages. 



J. ROBB, M.D. 



Explanation of the Plate. 



Fig. 1. Ordinary form of the abortive 

 fruit, nat. size. 



a. Peduncle. 



b. Witliered remains of corolla and 

 stamen. 



c. Groove or suture, indicating the 

 edges of the protophyllum. 



d. Withered style. 

 «. Normal form of the fruit. 

 Fig. 2. Abortive plum which has be- 

 come elongated like a pod, nat. size. 



Fig. 3. Another variety, rounded and 

 much corrugated, nat. size. 



Fig. 4. Section of Fig. 1., a little mag- 

 nified. 



/. /. Cut edges of exocarp. 



g- Cellular tissue of mesocarp. 



A. Large bundle of vessels, reaching 

 from the peduncle to the base of the 

 style, and corresponding to the pla- 

 centa in leguminous plants. 



i- Endocarp, suspended from the pla- 

 cental vessels, and being almost loose 

 on the mesocaiT). 



A. Section of a plum, ripening in the 

 normal way. 



Tab. IV. 



Fig. 5. Magnified view of a piece of 

 the carpel, to show the attachment 

 of the endocarp. 



I. I. Marginal vessels of the protophyl- 

 lum. 



m. Funicle or vascular connexion of 

 the ovule, and its coverings. 



Fig. 6. Endocarp, opened and magni- 

 fied, to show the ovules. 



i. Internal surface of the endocarp. 



m. Funicle or vascular cord. 



M. 0. The two ovules not attached to 

 each other. 



p. Vessels going off from the placenta, 

 to one of the ovules. 



Fig. 7. Magnified section of one of 

 the ovules. 

 p. Connecting vessels, 



q. Membrane, by which the ovule is 

 also attached. 



r. Cut edge of the outer sac. 



s. Cut edge of the middle sac. 



t. Innermost shut sac containing a clear 

 fluid. 



XI A Sketch of the Progress of Botany in Western America. 



By C. W. Short, M.D. 

 \^From the Transylvania Journal of Medicine, No. XXXV.'] 



[The Flora of North America has long occupied much of our attention ; 

 and thanks to the liberality of our own Botanists and those of the United 

 States, there is no herbarium in Europe that includes so large a collection 

 of American plants as our own. We have ourselves in the Edinburgh 

 Vol. III.— No. 18. o 



