496 Palaeontologie. 



Als neu werden angegeben für Mittelrussland: Cinna pen- 

 dula und Glyceria nemoralis, für das Vladimir 'sehe Gouvernement: 

 Hypericum hirsutiim, Ribescaucasicuin, R.grossularia, Salvia verticülata \'on 

 seltenen Pflanzen für das Gebiet werden aufgezählt: Brachypodium pin- 

 natiim, Cephalanthera rubra, Cypripediiim Calceolus, Glyceria plicata, 

 Isoeies lacustris, Ranunculus Purshii, Rhamnus cathartica. 



G. Westberg (Riga). 



Arber, E. A. N., On the roots o\ Medullosa anglica. (Annais 

 of Botany. Vol. XVII. 1903. p. 425—433 and PI. XX.) 



The first account of the structure of the roots of a Medul- 

 losa was given by Dr. Scott in 1899. A specinien of Medul- 

 losa anglica Scott now in the Sedgwick (Wood war dian) 

 Museum, Cambridge, has recently been found to contain 

 some exceedingly well preserved roots which are here descri- 

 bed and figured. They agree very closely with the roots of 

 this species described by Dr. Scott, which were also obtained 

 from the Lower Goal Measures of Lancashire. Two 

 complete transverse sections of the root are figured, and more 

 highly magnified portions of the thin-walled tissues lying inter- 

 nal to the periderm, and between the periderm and the xylem, 

 bring out more clearly, than was possible in the specimens 

 previously described, the details of the anatomy of this region. 



The phellogen and phelloderm, the latter being comparati- 

 vely thin, are well seen. The pericycle constitutes a fairly 

 broad band of parenchymatous tissue, containing numerous 

 „secretory sacs", which appear to be of parenchymatous nature, 

 and which also occur among the parenchymatous Clements in 

 all parts of the root. 



The structure of the phloem and its conjunctive parenchy- 

 ma is very clear. The secondary phloem consists of radial 

 groups of rather small cells, the sieve tubes alternating with 

 rays of much larger phloem parenchyma. 



The secondary bast as a whole has much the appearance 

 and structure of that of the stem of Heteranglum tillaeoides 

 Will., a new point of agreement between Medullosa and Hete- 

 ranglum. Lateral sieve plates, which are figured, are recogni- 

 sed here for the first time in both the stem and roots of 

 M. anglica. 



Some further details with regard to the secondary roots 

 have been made out. The lateral rootlets arise in three rows 

 at points opposite the three protoxylem groups of the root, 

 but only one rootlet is given off in any one transverse plane. 

 The xylem of the rootlet arises opposite one of the protoxylem 

 groups of the main root. Other details as to the origin of the 

 rootlets are described and figured. Arber (Cambridge). 



Ausgegeben: 17. November 1903. 



Comiiiissions-Verlag: E. J. Brill in Luiden (Holland). 

 Druck von Gebrüder Gotthelft, Kgl. Holbuchdrucker in Cassel. 



