Linnaan Society. 353 



December 2.— E. Forster, Esq., V.P., in the Chair. 



Read a paper '* On the Anatomy of Eriocaulonece." By the late 

 William Griffith. Esq., F.L.S. &c. Communicated by R. H. Solly, 

 Esq., F.R.S., L.S. &c. 



The observations on which this memoir (written at Calcutta in 

 1835) was founded, were made at Mergui between the months of 

 July and October 1834. The species examined were natives of that 

 place, and six in number. They appear to be destitute of true spi- 

 ral vessels, the place of which is supplied by ducts occasionally, but 

 not freely, unrollable, aggregated in distinct fascicles and surrounded 

 by more or less elongated cells. 



Mr. Griffith describes the leaves oi Eriocaulon setaceiim,L., as the 

 type of these organs in the genus, since they are in it reduced to 

 the simplest state. They are submerged in this species, and the pe- 

 duncles and their sheaths only rise above the surface of the water. 

 The leaves are subulate, somewhat flattened and colourless below, 

 green on their upper surface, and divided throughout their entire 

 length into two distinct collateral tubes, by means of the central and 

 only nerve which is attached both to the superior and inferior cutis 

 by cellular tissue. Numerous transverse septa of cellular tissue 

 divide each tube into chambers, which, however, have free commu- 

 nication with each other through fissures dependent on a partial 

 separation of the cells. The green parenchyma is almost entirely 

 confined to the upper half of each tube, and ceases abruptly with- 

 out any apparent cause. It consists of a single layer of colourless 

 oval or roundish sacs, arranged with the most beautiful regularity in 

 longitudinal lines extending from the base to the apex of the leaf, 

 and corresponding with the bodies of the cells forming the cutis and 

 not with the intervals between them. The stomata are confined to 

 the under halves of the leaves, or to that portion of the tubes which 

 is destitute of parenchymatous tissue. 



In the terrestrial species the structure of the leaves is essentially 

 the same, but the number of longitudinal tubes is increased, and va- 

 ries from six to twenty, the central ones only reaching the apex of 

 the leaf. The longitudinal divisions between these tubes are marked 

 externally by corresponding depressions, and each is furnished with 

 a vascular fascicle similar in structure and position to that of E. se- 

 taceum. The parenchymatous cells are arranged with less symme- 

 try than in that species, and are not so completely confined to the 

 upper surface ; and the lower surface abounds with stomata. 



The sheaths which envelope the base of the peduncle have in all 

 the same organization, which is exactly that of the leaves of the ter- 

 restrial species. The peduncles are also composed of tubes, circu- 

 larly arranged ; they are marked externally with elevated whitish 

 lines, which (in the living plant) have a slightly spiral direction 

 from left to right, and correspond to the longitudinal septa. The 

 tubes meet in a cellular axis, around which the vascular fascicles are 

 arranged in corresponding number; and the septa form so many 

 spokes consisting of more or less elongated cellular tissue, which in 



