210 



G. ORSHAN 



X XI XII I 



I III IV V VI Vll VIII X 



Fig. 2. Life cycle of Teucriuni polium. 



(a) The lower part of a dolichoblast developed during the previous spring bearing 

 small partial brachyblasts (i). 



(b & c) One of the brachyblasts of the same branch turning into a new dolichoblast 

 bearing winter leaves (2). 



(d) The same dolichoblast reaching its maximal height. The older winter leaves 

 have already been shed and new brachyblasts (4) have developed in their axils. 

 (3) The inflorescence. 



(e) All the winter leaves already shed. The upper brachyblasts slowly elongating (5). 



H leaves absent 

 leaves developing 

 ^ leaves persisting 

 [y leaves being shed 



Upper row -winter leaves 

 Lower row -summer leaves 



leaves of the dolichoblasts, and the brachyblasts then look like small open 

 rosettes. Meanwhile practically all the summer leaves are shed. In February, 

 the inflorescences are developed at the apices of these brachyblasts. By that 

 time the new^ dohchoblasts start developing either from renewal buds 

 formed on older branches or as axiUary buds on the brachyblasts. The 

 autumn leaves of the brachyblasts are gradually shed in March and the 

 beginning of April. The upper portions of the dohchoblasts die back during 

 the end of their first summer (Fig. 3). 



(d) Artemisia herha alba. The dohchoblasts start elongating in the autumn 

 (October to December) from temporary brachyblasts or from renewal 

 buds. Their growth rate is slow in the early winter but increases rapidly 

 towards the spring .During April and May these stems branch once or twice 

 in their upper part and the inflorescence develop at their tops in September 

 and October. The plant sets fruit druing November and December. 



There is a gradual change in leaf size and form from the base to the tops 



