The Structure of Isoetes Hystrix, 
BY 
D. H. SCOTT, M.A., Ph.D., F.R.S., 
Honorary Keeper of the Jodrell Laboratory, Royal Gardens , Kew, 
AND 
T. G. HILL, 
Late Marshall Scholar , Royal College of Science, London. 
With Plates XXIII and XXIV, and two Figures in the Text, 
Introduction. 
I N April and May, 1899, one of us received, through the 
kindness of Mr. E. D. Marquand, a number of fresh 
specimens of Isoetes Hystrix , collected by Mr. George Derrick, 
a botanist resident in Guernsey, at the well-known locality 
on 1 ’Ancresse Common, in that island, the only known British 
habitat for the species k To both the gentlemen mentioned 
our best thanks are due. This material, which included 
plants of very different ages, afforded a welcome opportunity 
for a re-investigation of the structure in this form, which is 
of considerable interest as being one of the terrestrial species, 
1 See Mr. Marquand’s note on the genus Lsoetes , in Trans. Guernsey Soc. of Nat. 
Science, 1889, p. 123. 
[Annals of Botany, Vol. XIV. No. LV. September, 1900.] 
