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1897.] NATURAL SCIENCES OF PHILADELPHIA. 197 



This season T have had a piece of good fortune; it is' interesting 

 enough to give the discovery in detail : — 



On my grounds I have a mass of Cassia Marilandica, probably 

 fifty plants, covering an area of about sixteen square feet. The 

 leaves are, normally, abruptly pinnate, having a number of pairs of 

 opposite pinna? with a gland terminating the common petiole. The 

 base of the petiole is tumid, and usually the " gland " arises on the 

 upper surface of the petiole, just above this tumid part. This, how- 

 ever, is not constant. In some cases I found the " gland " a quarter 

 of an inch, a half inch, an inch, and, in a few cases, as much as two 

 inches away. In a few instances they were found with fully-de- 

 veloped pinnae on either side of them, presenting precisely the ap- 

 pearance of tbe terminal pair at the apex of the common petiole. 

 As the terminal one has developed with a perfect leaf in some in- 

 stances, as already noted, it must be assumed that these at the base 

 of the leaf could, under equally favorable conditions, do the same; 

 in their nature they are identical. 



Besides this positive proof, the larger basal glands will occasion- 

 ally furnish strong presumptive proof. These bodies vary much in 

 form, sometimes narrow cylindrical, sometimes nearly globular, at 

 other times are found some remarkably vigorous and ovoid. At 

 the apex may often be seen a pair of small glands in the posi- 

 tion that two opposite leaflets would occupy, with a very small 

 gland between, just as we find at the apex of the common petiole. 

 No one comparing such a gland with the apex of a leaf could come 

 to any other conclusion than that the two were normally the same, 

 except that the two leaflets had not developed, leaving only a pair 

 of glands to represent them. 



But, it might be suggested, this would only show that the gland 

 was an undeveloped compound leaf; the proof that it was an un- 

 developed branch would be still desirable. Here we have to fall 

 back on advanced knowledge in vegetable morphology. Most 

 botanists are now prepared to believe that not only are the organs 

 of flowers to be conceived of as modified leaves, but the stem itself 

 comes under the same conception. The cell is the primary plant. 

 Whatever form the plant has to take ultimately, is governed by 

 laws operating in this primary cell. The next step in the concep- 

 tion is the union of cells so as to form leaf-blade, and the next the 

 coiling of leaf-blade to form stem, the upper portion of each coil 

 finally becoming the leaf. There is abundant evidence, not neces- 

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