701 



A UMVISION OF THE INDIAN SPECIES OF WTALA 



AND AMMANNIA. 



15Y 



K. Blatter, S..)., and Prof. F. Hallberg. 



Since ('. B. Clarke described the Indian Li/fhracerxi in Hooker's 

 llova of British India (Vol. II, 1879) a number of new species have 

 been described, but, niifortnnately, the chief literature seems to be 

 confined to a few botanical centres in Eiu'ope. Even those botanists 

 \\lio have written local floras during the last twenty j'ears were 

 ap])arently not aware of some important publications regarding the 

 order Li/tkracete. The consequence is that many mistakes as to 

 identification, description, and synonymy have crept into the more 

 recent works on Indian botany. This is quite particularly the 

 case with regard to the genus Ammaiinia (sens, ampl.). We are 

 sure, everybody who has ever tried to name members of that genus 

 nnist have experienced the great difficulties which arise, partly from 

 the small size of the flowers, and partly from the want of well- 

 defined species and adequate descriptions, not to mention evident 

 mistakes that have been perpetuated in consequence of the com- 

 Vunation of diagnoses which, originally, referred to distinct species. 

 The fact, that many identifications in European as well as Indian 

 herbaria are wrong or at least doubtful, has induced us to revise the 

 genus as far as the Indian region is concerned. We must acknow- 

 ledge our indebtedness to Koehne who monographed the Lythraceoe 

 in 1003 (Engl. Pflanzenr. IV, 216). How far we agree with his 

 treatment of the subject will be seen from our -paper. We wish to 

 thank the curators of the Herbaria of Calcutta, ]\Iadras, and 

 Baroda, and Mr. Sedgwick for kindly putting their plant-material 

 at our disposal. The number of specimens examined amounts to 

 almost two thousand. 



Bentham and Hooker divide their genus Ammannia into two 

 sections and they call the division a very natural one. Clarke 

 considers the two sections as two sub-genera and calls them respec- 

 tively : Jlotala and Eu- Ammannia. At the same time there have 

 always been a number of botanists who distinguished the genera 

 Rotala and Ammojinia. We follow the latter. Botala L. is charac- 

 terized by septicidal capsules, whilst Ammannia has the capsules 

 indehiscent, or bursting irregularly. 



Rotala, L. (sens. ampl.). 



Annual or more rarel}' perennial, water-or marsh-plants, quite 

 glabrous. Leaves decussate or verticillate, rarely alternate, sessile 

 or subsessile. Flowers small, solitar^'-axillary, or forming spikes 

 or terminal racemes, rarely axillary umbels ; bracteolee 2, rarely 



