4.S2 



PHANEROGAMS. 



ti Stronger growth and slower production of divisions, which are formed more 

 rapidly in the surromiding meristem. This layer consists of the primary mother- 



FlG. 343. — Fjotkia cordata ; A transverse section through a 

 young pollen-sac before the isolation of the mother-cells S7n, 

 ep the epithelium which clothes the anther-lobe, iv wall of the 

 pollen-sac ; B the anther-lobe after isolation of the mother-cells 

 sm ; ep indication of the epithelium ( X 500). 



Fig. 344. — Mode of formation of the pollen ol Funkia ' 

 ovata (X550). In VII the wall of the daughter-cell has 

 absorbed water till it has burst ; its protoplasm is forcing 

 itself out through the fissure, and is lying before it 

 rounded off into a spherical form. 



Fig. 345.— .5 a young pollen-cell oi Funkia ovata ; the thickenings which project outwardly are still small, in the 

 older pollen-cell C they are larger ; they are arranged in lines connected into a net-work. 



cells of the pollen, which produce, by a few further divisions, a longish assemblage 

 of mother-cells united into a tissue (Fig. 343, A, sm; Fig. 346, ?n) ; the whole large- 

 celled mass being surrounded on the outside by a small-celled tissue consisting of 



so that usually only one layer remains ; and this, together with the epidermis, forms the wall of the 

 anther.' 



