MIDDLE EUROPE. 267 



Mdgen (1900 : 145) has grouped the stages of succession at Kaiserstuhl, 

 Germany, in the following formations : 



(1) Initial, Sedetum euphorbiosum, S. alyssosum, S. scrofulariosum, S. coro- 

 nillosum, S. mixta; (2) herb-land, Thymetum teucriosum, T. seseliosum, T. 

 graminosum, T. euphorbiosum, Euphorbietum graminosum; (3) meadow, Bro- 

 metum thymosum, B. hippocrepidosum, B. sanguisorbosum, B. teucriosum, B. 

 onobrychosum; (4) scrub, Prunetum teucriosum, P. fniticosum, P tanacetosum, 

 Coryletum coronillosum, Cornetum coronillosum, Quercetum coronillosum, Q. 

 convallariosum; (5) forest, Quercetum arboreum, Q.fagosum,Fagetumguercosum, 

 F. muscosum, F. asperulosum. 



Waldvogel (1901) has studied the vegetation of the Liitzel See and its valley,- 

 with a clear distinction of associations and various developmental indications: 



The chief vegetation is the moor, Hypneto-Phragmitetum, with many species 

 of Carex and Equisetum. The lake was formerly much more extensive, as 

 shown by the remains of water-plants (Nuphar, Nymphaea, Trapa) and by 

 fruits of trees found in the lowermost layers of turf. The meadows exhibit the 

 following associations: Molinieto-Anthoxanthetum, Phragmiteto-Panicetum, 

 Paniceto-Molinietum, Phragmiteto-Strictetum. The reclaimed area is domi- 

 nated by Carex stricta. The aquatic and amphibious associations are Cariceto- 

 Phragmitetum, Characetum-Sdrpetum, Potamogetonetum, Nupharetum, and 

 Myriophylletum. 



Weber (1901), in connection with the conservation of natural formations in 

 Germany, has laid down certain rules which simmiarize the changes which 

 produce secondary successions: 



Change of the ground-water of moors is to be avoided by forbidding the 

 digging of peat within 500 m. of the area to be conserved. If mowing and the 

 erdarging of ditches are stopped, moor will again exhibit its natiiral composi- 

 tion. The development of woodland on heath is to be prevented by grazing 

 sheep, while in the case of certain heaths and moors, drainage is not to be 

 abandoned, as the vegetation will change. 



Schroter (1902) has given a comprehensive analysis of the structiu-e of the 

 vegetation of Lake Constance. Although not intended as a study of succession, 

 the sequence of formations and " bestande " indicates clearly the serai relations, 

 as is shown by the following sxunmary: 



A. Phytoplankton. C. Phytobenthos — Continued. 



I. Formation of limnoplankton. VI. Linmaean formation. 



(1) Cyclotelletum. (8) Characetum. 



B. Pleuston. (9) Potamogetonetum. 



II. Formation of emersed hydrocharids. (10) Nupharetum. 



(2) Lemnetimi. VII. Reed-swamp formation. 



III. Formation of submersed hydro- (11) Scirpetimi. 



charids. (12) Phragmitetum. 



(3) CeratophyEetum. VIII. Amphiphyte formation. 



(4) Scenedesmetum. (13) Heleocharetum. 



(5) Zygnemetum. (14) Polygonetum. 



C. Phytobenthos. IX. Formation of alluvial plants. 



IV. Formation of Schizophyceae. (15) Tamaricetum. 



(6) Beggiatoetum. X. Sedge formation (Magno-carice- 



V. Nereid formation. turn). 



(7) Encyonemetum. (16) Strictetum. 



Weber (1902) has made an exhaustive study of the moor of Augstumal in 

 Germany, and has instituted comparisons between it and other high moors. 

 The various formations of the moor are recognized and described in detail: 



