Fig. 136 Gigartina. Left, plant of G. calif ornica; (original, x \). 

 Centre, carpogonial branch, G. stellata ( x 1500); cp. = carpogon- 

 ium; s.b. = vegetative lateral; s.c. = support cell. Right, t.s. thallus, 

 G. stellata ( x 160); a = outer cells; b = inner cells (both after 



Newton). 



plants have papillose projections (the cystocarps) from the surface 

 of the thallus. The internal construction consists of a mass of large 

 central cells with smaller cells towards the periphery. The limiting 

 layer consists of very small cells, the whole being based upon the 

 multiaxial type of construction. In some species, e.g. G. stellata, 

 the cells of inner cortex and medulla give rise to down-growing 

 septate hyphae. The carpogonial branch is three-celled and is de- 

 rived from a large support cell of the inner cortex, which also 

 fimctions as the auxiliary cell. In addition to the carpogonial branch 

 the support cell either produces a vegetative lateral or a second 

 carpogonial branch. 



Phyllophoraceae : Phyllophora (phyllo, leaf; phora, bear). Figs. 



137. 138 



The stipitate fronds expand upwards into a rigid or membranous 

 flat lamina which is either simple or divided, whilst proliferations 

 may also arise from the margin or basal disc. Morphologically the 

 thallus is multiaxial and composed of oblong polygonal cells in the 

 central medullary region, whilst the outer cortical layers consist 

 of minute, vertically seriate, assimilatory cells. In some species 



243 



