' THE GENUS ROTULA 969 
of a new species of Udotea collected long since at the island of 
St. Thomas by the ‘Challenger’ Expedition, and preserved in the 
British Museum. | 
verticillos similes emittentibus, parietibus incrassatis. 
_ Hab. West Indies, St. Thomas, five to fifteen fathoms, ‘ Chal- 
lenger’ Expedition. 
Its nearest ally is U, argentea Zan., which differs in having the 
— appendages of its frond-filaments capitate and more longly 
stalked. . 
THE GENUS ROTULA. 
By Rosert Huer Buntina. 
Louremo’s genus Rotula (Fl. Cochinch. 1790, p. 121) is 
referred tentatively by Bentham and Hooker (Gen. Plant. ii. 
to R ; . Gen. et Sp. Pl. ii. 186); in the 
Index Kewensis and by Mr. C. B. Clarke (FI. Brit. India, iy. 145) 
u 
authenticated specimens of Rhabdia lycioides, since, if the two 
; was first 
lycioides from Nepal (Wallich No. 9062)... 
_ Transverse sections of the oldest branch of Rotula show it to 
have been collected in the early part of its second year’s growth. 
The pith consists of parenchymatous cells fairly’ large in the 
centre but decreasing in size towards the xylem; there are no 
intercellular spaces. The xylem is chiefly composed of tracheids 
with a few large vessels scattered about in groups of two to five; 
the tracheids bordering the medullary rays are more or less rect- 
* Loureiro sent in 1774 a small collection of plants to Captain Riddel, who 
subsequently presented it to Banks. e Journ. Bot. 1902, 389. 
Journat or Borany.—Von. 47. [Juny, 1909.] Y 
