400 On Rotation in the pith cells of Saururus cemuus. 



In parts of the same specimens the tabes are free, only con- 

 nected by lateral processes, and exhibit all the characters de- 

 scribed by Billings in Haimeophyllum ordinatum (Canad. Journ., 

 18o9, p. 140). This species consequently has to receive the 

 name Haimeophyllum, the affinity of which to Michelinia is 

 already mentioned in Mr. Billings's essay. 



Art. XXXVIL— 0/z , 



cells of Saururus cemuus ; by Geoege C. Schaeffee, M.I 



While examining the intimate 



discovered, in th 



year 1854, a peculiar i 



pith cells of Saururus cemuus, which was so different from any 

 thing before described that it seemed to be quite abnormal. Con- 

 tinued observation for eight years has shown however that, for 

 this plant at least, the phenomenon is constant, while an equally 

 long continued examination of the writers on such subjects, has 

 proved that no record of this appearance has ever been made. 

 As a mere microscopical curiosity the fact might be deemed wor- 

 thy of notice, but the remarkable similarity to a motion which 

 has been considered as invariably connected with a distinct and 

 peculiar vegetable function, seems to render its record needful 

 for the true advancement of vegetable physiology. 



Ihe Saururus cemuus, like many other aquatic or marsh 

 plants, has a pith, the cells of which are not in complete juxta- 

 position, but separated in part by vertical air passages which are 

 as regularly built around by the cells as a chimney is by its 

 bricks, with this difference, however, that the cells are arranged 

 directly one above another, and do not "break joint" as the 

 bricks would in any properly constructed chimney— no fault in 

 mture s workmanship, we should remark, since the pith is a 

 mere filling in, surrounded by a much denser and more solidly 

 budt structure. 



The cells in which the above mentioned motion occurs are not 

 those from which the party walls of each air passage diverge, 

 but those forming the middle of the wall between any two con- 

 tiguous channels; they seem to be smaller and younger cells 

 than the others. 



In all ordinary cases of cychsis the motion is along the walls 

 of the cell, coming and going in paths which are, for the time at 

 least, permanent. But in the Saururus the granules lie in the 

 centre of the cells above described and their motion is of a quite 

 different character. To those familiar with microscopic obser- 

 vations, we may best describe this motion as perfectly identical 

 witti that seen in the, so-called, vesicles, in the ends of ChsU- 



