h 



Allgemeines. — Anatomie. — Biologie. 515 



Class VI. Autonomie land-plants. 



Subclass I. „Hapaxanths", plants flowering once only. — „Pollak- 

 anths", plants flowering repeatedly, are all the following: 



Subclass 2. „Redivivic herbs", perennial herbs whose aerial 

 shoots disappear in the unfavourable season, They have mostly long 

 internodes. Stolons can be present 



Subclass 3. „Rosette-plants", plants with rotulate leaves. The 

 shoot is as a rule evergreen, Hereto also some trees: Cycas, Aloe etc. 



Probably the rosette-plants are formed by direct adaptation of 

 plants with long-shoots. They are to be found principally in tempe- 

 rate, subnival and desert climates. 



Subclass 4. Plants trailing above ground. The shoots are dorsi- 

 ventral, the leaves disposed in two rows and have particular forms. 

 Moist soil near water and in forest and warm soil on rocks or sand 

 are favourable for the appearance of trailing plants, and so is Psy- 

 chrocliny, long shoots in cold growing prostrate. 



Subclass 5. Plants with erect and persisting long-shoots. 



To this subclass belong many passivly prostrate plants and 

 cushionplants. The latter show epharmonical convergence, appearing 

 in many countries. As efficient causes for the cushion-form rough 

 climate and especially wind are mentioned. Further belongs to this 

 subclass: suffrutescents, whose aerial shoots partly die in the unfa- 

 vourable season, — plants with soft perennial stems, succulents, 

 and Woody plants. 



As to further subdivisions few details are given. 



The fifth chapter deals with „The leaf and the leaf-shoot", giving 

 an account of different leaf-structures and their connection with the 

 outer factors. Specially adaptations to drought are mentioned. 



Ove Paulsen. 



Petersen, H. E., The biological anatomy of the leaves and 

 of the stems of Ericineae. (The structure and biology of 

 arctic flowering plants. I. Ericineae, 2). (Meddelelser om Grön- 

 land, 36. Copenhagen 1908. p. 75 — 138. 39 figures in the text. 



The anatomy of the following species is described: Andromeda 

 polifolia, Arctostaphylos alpina, A. Uva-ursi, Cassiope hypnoides, C. 

 tetragona, Chimophila unibellata, Ledum palustre, Loiseleuria procutn- 

 bens, Lyonia calyculata, Phyllodoce coerulea, Pirola grandißora, P. 

 minor, P. rotundifoUa, P. uniflora, P. secunda, Rhododendron lap- 

 ponicum , Vacciniiim Myrtillus, V. Oxycoccos, V. uliginosum, V. 

 Vitis-idaea. 



The author discusses the structure of the different species in 

 connection with their distribution now and formerly. Most in con- 

 formity with the arctic climate are: among the evergreen species 

 Rhodo dendronlapponicum, Ledum and Cassiope tetragona, and among 

 the deciduous species Vacciftium uliginosum. Especially Rhododen- 

 dron and Cassiope have well protected leaves, — they are both true 

 arctic species, probably long-established in arctic regions. 



There was observed only a slight difference in the xerophytic 

 structure of the North-European and of the Arctic individuals of the 

 same (evergreen) species, but perhaps this could be due to the fact 

 that winter-time does not in many points differ greatly in the loca- 

 lities in question. Ove Paulsen. 



Warming, E., Morphology and biology of Ericineae. (The 



