BULLETIN 



OF THE 



TORREY BOTANICAL CLUB 



Vol. XV.] New York, February 1, 1888. [No. 2. 



On the Histology of the Vegetative Organs of Brasenia peltata, Pursh.* 



Bv. Joseph Schrenk. 



Plates LXXVTI and LXXVIIL 



In October, 1884, while examining the structure of the stem 

 and petiole of Brasenia peltata, I found some peculiar hairs 

 projecting into the wide intercellular air-passages, which were 

 entirely different from the so-called ' internal hairs ' o{ NympheEa^ 

 Ntipkar and LhnnantheniiimA 



About two years later, similar hairs were noticed by J. F. A. 

 Mellink in some petioles of Nymplwea alba collected by DeVries 

 in Amsterdam, and described in Botanische Zeitung, Nov. 5. 1886. 



Since that time I have carefully examined these structures, 

 and, finding other remarkable peculiarities about this common 

 water-plant, I thought them of sufficient interest to be placed on 

 record. 



What is described in the manuals as the creeping rootstock, 

 is really a system of runners that proceed from the rhizoma prop- 

 er. This must be rarely fully developed, for although I repeated- 

 ly searched for it carefully, I could find only few specimens. 

 They were only from two to four cm. long and up to one cm. 

 thick, and had very short internodes, so that they appeared cov- 

 ered with the scars caused by the faUing off of petioles and stems 

 of former seasons. From the rootstock proper grow the leaves and 

 in their axils the stems. Many of the latter develop into stout 

 runners, creeping on the surface of the ground, with internodes 



* Read at the meeting of the A. A. A. S., at New York, Aug. 15 and 16, 1887, 

 to which a few more recent observations have been added. 



t T briefly described them at the October meeting of the Torrey Botanical Club (as 

 appears from the report of that meeting in the Bulletin), and exhibited some slides 

 with mounted specimens. Mr. P. H. Dudley had the kindness to photograph one of 

 the sections, showing an air-passage with some of these hairs. 



