188 PROCEEDINGS OF THE ACADEMY OF [1893. 



THE GLANDULAR HAIRS OF BRASENIA PELTATA PURSH. 

 BY IDA A. KELLER. 



The thick coating of jelly with which certain parts of Brasenia 

 peltata are covered can not have escaped the attention of any one 

 who is familiar with that member of the family of Nymphseacese. 

 In my search for descriptions of the method of formation of this 

 secretion, for such we must term the jelly-like mass, I have found 

 but one brief statement in explanation of the development of it. 

 This is by Asa Gray, who says " The jelly by which the stalks, etc., 

 are thickly coated, I find to arise from the rapid formation and 

 rupturing of successive epithelial cells, in the same way that muci- 

 lage is formed on the surface of animal mucous membranes." 1 This 

 explanation is wholly inadequate, and I might also say entirely 

 incorrect, as will become apparent further on. 



Turning our attention first of all to the distribution of the jelly, 

 it may be noticed in the plant represented on Plate III, fig. 1, that 

 there is none of this coating substance to be found on the older parts 

 of the creeping rhizome, and particularly not at such portions which 

 were not of this year's growth, nor is any of the secretion observ- 

 able on the petioles and blades of the older leaves still alive and 

 vegetating. Three such leaves are represented by B, C, & A, in 

 fig. I. On these, none of the jelly except perhaps slight traces of 

 it, was perceptible to the touch. The next two leaves, D, & E, in 

 fig. I, evidently younger and less well developed, show a thick film 

 of jelly-like substance on the petioles, and this film extended also 

 over the under surface of the leaf blades. The leaves of Brasenia 

 peltata are alternate and elliptical in shape, and centrally peltate. 

 The long diameter of each of the three older leaves above referred 

 tcu as destitute of the coating of jelly was about 8 cm. The long 

 diameter of each of the two leaves with the jelly-like coating on the 

 petioles and under leaf-surfaces was 7 cm. and 62 cm. respectively. 



The leaves are involute in vernation, and the next younger leaf 

 having not yet expanded, fig. I F shows the sides rolled inward, 

 parallel to the longest diameter. This latter measured 5 cm. The 

 entire leaf in this case seemed to be enveloped in a gelatinous sheath. 

 On unrolling the sides I found, however, that the secretion originated 



1 A. Gray, Genera Floras America; Boreali-Orientalis, Vol. I, p. 96, Note. 



