VOL. XLIV.] PHILOSOPHICAL TRANSACTIONS. 26l 



Ehret to draw not only this plant, but also the cicuta aquatica of Wepfer ; that 

 they might be the more easily known from all plants, and distinguished from 

 each other by their being both seen at one view. 



P. S. Mr. W. was informed by Mr. Ehret, that, in drawing the oenanthe,, 

 which he has executed with his usual elegance and accuracy, he was obliged to 

 have a quantity of it placed before him on a table ; when, the room being small, 

 its effluvia caused in him a universal uneasiness, with a vertigo ; so that he was 

 constrained to have it removed, and never after placed before him but a small 

 piece at a time. 



There is something in the formation of the root of the cicuta aquatica before- 

 mentioned, deserving particular notice. This plant generally grows either near 

 the sides of large stagnant waters, or in shallow rivers of slow streams. Towards 

 the end of autumn, or the beginning of winter, the root for the succeeding 

 summer is formed out of the lower part of the stalk. Out of the crown of this 

 root are then seen the rudiments of the leaves of next year ; and from the sides 

 of this grow the crowns of several smaller roots. This root, in its whole length, 

 is divided transversely into a number of large unequal cells. Corresponding with 

 the partitions, which divide these cells, the surface of the root is marked circu- 

 larly with little round deptessions. So great a part of this root is occupied by 

 the cells, that it becomes specifically lighter than water ; so that in winter, on 

 the increase of water in the rivers and pools, this root, as well that part intended 

 for the succeeding summer, as that which furnished the plant the preceding, is 

 buoyed up. The old root then rots, and floats on the surface of the water with 

 the new one all the winter ; and in rivers these are frequently carried to very 

 great distances from the places of their growth. In the spring the old root is 

 washed away ; and the new one on its coming near the soil, sends out from the 

 circles before mentioned, particularly from those nearest the bottom, a great 

 number of long slender white fibres, by which this root becomes again fixed to 

 the soil, propagates its species, and remains thus, until by the rotting of these 

 fibres it is again weighed up. The old root decaying, and being washed from, 

 the new, is the cause of that truncated appearance observed in the root of the 

 figures of Dodonaeus, Parkinson, and Morrison, who have exhibited this plant 

 in a flowering state. This provision of cells in the root seems to be given to 

 this plant by nature, that as great part of its root is apt to perish in winter, ve- 

 getation might not be prevented, nor the root destroyed, unless the whole num- 

 ber of cells are spoiled, which very rarely happens. 



Explanation of fig. 11, pi. 6, exhibiting the oenanthe eicutae facie.* a, its 

 tuberose roots surrounding the stalk, b, b, b, b, a leaf taken from near the 



* Oenaothe crocata Linn. 



