360 MR. JAMES GROVES: 
Indian area, as laid down in C. B. Clarke's paper on the subsubareas of British 
India in the Society’s Journal, xxxiv. p. 1, 1898; and I have made use of 
Mr. Clarke’s districts in arranging the records. 
I have added a rough key to the genera and species for the benefit of 
those towhom Braun and Nordstedt’s invaluable ** Fragmente” is not accessible. 
Like all keys, this must be used with caution or it may mislead in the case 
of extreme or abnormal forms. To the actual key characters I have added 
a few further particulars which may be of use. 
Under each species indieations of the known distribution outside the 
Indian area are given. Considering the many countries which have still 
been imperfectly searched for these plants, it is perhaps somewhat premature 
to attempt to generalize on their distribution, but the particulars furnished 
may afford some idea of the various elements which make up the Indian 
Charophyte-flora. 
I have ventured to make a rather important modification of Braun’s main 
divisions of the genus Nitella, by elevating to the first rank the sections 
FHomaocleme and Heteroclemw (Homa@ophylla and Heterophylla, Braun). 
The characters on which these are based appear to represent à more 
important and constant structural difference than the number of cells of 
which the ultimate ray is composed. Professor Ernst’s paper * Die Stipular- 
blätter von Nitella hyalina (DC.) Ag.” (Viertelj. Naturf. Gesellsch. Zürich, 
xlix. 1904) has largely influenced me in coming to this conclusion. 
My best thanks are due to the many friends and correspondents who have 
sent me specimens, to Sir David Prain for the opportunity of examining the 
entire collection of Charophyta at the Calcutta Botanic Gardens, and to the 
officials at Kew and in the Department of Botany of the British Museum, 
for referring specimens to us as well as for their kind assistance in con- 
sulting the herbaria. I am also much indebted to my friend Canon 
Bullock- Webster for his help in the examination of the oospore-membranes, 
to which difficult subject he has given special attention. 
Key TO THE GENERA. 
Coronula of oogonium composed of 10 cells in 2 tiers. — Branchlets 
usually fureate. Stem and branchlets entirely without cortex ...... Nitelleæ. 
Antheridia terminal (in sp. 1 some also lateral), produced between 
the forks of the branchlets, Oogonia and oospores laterally 
compressed, hence elliptic in transverse section ........... nn l. NITELIA. 
Antheridia produced laterally at the nodes of the branchlets. 
Oogonia and oospores not laterally compressed, hence terete in 
transverse SECtiON ......... ........,,.,,....,,,,,,.. eines 2. ToLYPELLA. 
Coronula of oogonium composed of 5 cells in 1 tier. Oogonia and 
antheridia produced laterally at the nodes of the branchlets. 
Oogonia and oospores not laterally compressed. Stem and 
branchlets corticate or ecorticate |... seems Charez. 
Stipulodes absent. Stem and branchlets eeorticate. — Branchlets of 
2-3 very long segments, Braet-cells 1-2 at a node, very long... 3. NITELLOPSIS. 
