MK. J. SCOTT OT^ ISOETES CAPSTTLA-RTS. . 207 



bers of the Society who may not have facilities for consulting the 

 original works — all of which are scarce, though both originator and 

 transmitter are generally known for the acutencss and accuracy 

 with which they prosecuted their researches. The plant certainly 

 must have been scarcer in the ponds of the Botanic Grardenshere 

 in Eoxburgh's time than it now is ; otherwise that excellent ob- 

 server would certainly have detected his error, on seeing under a 

 noonday sun the innumerable florets freed from their spathes 

 and ascending like tiny air-globules till they reach the surface of 

 the water, where the calyx quickly bursts, — the two larger and 

 opposite sepals, reflex, forming tiny rudders, with the third and 

 smaller recurved as a miniature sail, conjointly facilitating in an 

 admirable manner the floret's mission to those of the emerging 

 females. These phenomena were perfectly familiar to Roxburgh 

 in two of his other Vallisnerias, the Necliamandra alternifolia^ 

 Planch., and the Sydrilla verticillata, Eich., both of which are 

 common here. Of V. spiralis, Linn., Roxburgh seems to have 

 been familiar with thejemale form only, which is described in his 



* ri- Indica,' vol. iii. p. 750, under the name of V. spiraloides, 

 though, singularly enough, in describing Isottes capsularis, Box- 

 burgh notices its Yallisnerioid leaves, and its occurrence with that 

 plant in fresh-water ponds. 



The plant figured by Griffith and referred to the Isoetes capsu- 

 laris^ Eoxb., is, as previously stated, a true Isottes^ and, I strongly 

 suspect, nothing else than the Z coromandeliana^ Linn., from culti- 

 vated specimens in Dr. Carey's gardens at Serampore, as I cannot 

 ascertain that any Isoetes is indigenous to that locality. Griffith 

 simply states " that it appears to be abundant around Serampore," 

 without giving his authority for the locality, undoubtedly referring 

 to Roxburgh's plant, which is common enough about Serampore, 

 and used extensively by the sugar-refiners for covering the surface 

 of their sugar to induce the slow percolation of water. 



[Since writing the above note, Mr. Kurz, curator of the herba- 

 rium here, has directed my attention to a pamphlet by Braun, 



* Isoetes- Arten,' in which I find the differences between Rox- 

 burgh's plant and that figured by Griffith correctly indicated 

 (the former as a phanerogam, the latter as a true IsoSfes) ; but, 

 from the want of original specimens, he admits his inability to give 

 the conspecific references : — 



" Z capsularis, Roxb., Icon. Roxb. t. 696. Capsules pedunclcd, 

 1 -celled. Leaves linear, flat. This plant grows in deep standing 

 sweet water, with Vallisneria spiraloides &c. 



