Goodlatte: The anatomy of Parosela spjnosa 579 



4, around the pith and within the leptome. These tannin elements 

 are not of invariable occurrence, he finds, in the Leguminosae, and 

 part of the tribe of the Galegeae is without them. Dalea^ how- 

 ever, belongs to the series provided with this sort of secretion 

 organ. These ducts contain in addition to tannin, he says, albu- 

 minous material which will stain bright yellow in iodine, although 

 the tannin interferes somewhat with the reaction. Weyland veri- 

 fies Baccarini's results in general, but finds that what he interpreted 

 as a transitory appearance of tannin-bearing elements is due to the 

 difference of the contents of the ducts at different stages. In the 

 young stem the contents are almost wholly albuminous and the 

 tannin appears later, which explains, he adds, the great size of the 

 ducts relative to the amount of tannin contained. 



In Dalea^ Weyland observed these ducts in the pith, Trecul in 

 the pith and the primary cortex as well. In the species under dis- 

 cussion, as far as the available material showed, they occur only in 

 the cortex. As has been said, the tests to determine the contents 

 w^ere most unsatisfactory. The ducts were filled with a substance of 

 red-brown color, and this of course made all those tests for tannin 

 which depend upon a red or a brown color-reaction, unavailable. 

 Copper acetate, iron sulphate, and iron acetate, which should give 

 green, black, or blue color, had apparently no effect. It seems 

 probable that the preserving liquid must have affected the contents 

 in some way, although the liquid itself, when tested for tannin, 

 showed no result, so that this could not have been extracted in any 

 large quantity. The arguments, then, for considering these ducts 

 as part of the albuminous-tanniferous apparatus similar to that of 

 other members of the genus and tribe, are simply based upon the 

 similarity in structure and position. The similarity in structure is 

 at once apparent and that in position is evident when one considers 

 Baccarini's statement that the cells normally lying on the sides of 

 the bundles of hard " libro," are sometimes pushed out till they 

 lie between the bundles. 



Another type of secretory organ which is very prominent in P. 

 spinosa is an ovoid schizogenous gland with an opening to the 

 exterior through a small slit, and surrounded by a firm layer of 

 close-set cells, which 'show traces of lignification, lined by a layer 

 of papillary epithelium, with densely granular cell-contents, light 



