60 Ellen Marion Delf 



or more. They are held at the base by a much branched hap- 

 teron. The stem is hollow when adult, and is swollen at the end 

 to form a float. In this region it bears a large number of flat 

 frond.*- which trail freely at or near the surface of the water. The 

 fronds are therefore comparatively well illuminated like those of 

 plants in shallow pools at low or mid-tide levels. The fronds 

 like the stems are long lived, but ultimately become fertile, bearing 

 a large number of sporangia. The dehiscence of these and the 

 behaviour of the spores when liberated has not yet been followed. 



Macroc^stis is a large kelp which is also knovm from the deep 

 water off the coasts of South America. On the shores of the 

 Cape it possesses a creeping rhizome-like base bearing many long 

 slender branches. These bear a series of distant leaflike appen- 

 dages which have a wrinkled lamina, and generally a pyriform 

 float at the base. A fair sized plant here reaches the length of 

 12-15 feet, and has a diameter of about ]/4 inch; the South Am- 

 erican form is said to reach much larger dimensions. Al the apex 

 of each branch is the region of differentiation of new fronds which 

 gradually split off from one another as they lengthen. At the base 

 of stem or '* stipe/' a leaf like frond may usually be seen wathout 

 a float, and it is possible that this may depend on the depth of the 

 water in which they are differentiated. At or near the base of 

 the elder stems, a short branch may occasionally be seen bearing 

 two or three flat fronds without a float; these are thin at first and 

 not wrinkled, but they become thicker and slimy in irregular 

 patches, where a large number of sporangia may be found. So 

 far as I am aware there are no previous records of the fertile 

 fronds of this plant. Occasionally, the fertile fronds are borne 

 on short stipes arising directly from the basal rhizome-like branches. 



The deep water red seaweeds of these shores are sufficiently 

 obvious when cast up after storms; they are often rose red when 

 fresh, turning dark red when dried. The large leathery red fronds 

 found in deep water near the Rogge Bay pier are Nemasioma 

 lanceolaia. The long more delicate fronds of Schizymenia undu- 

 lata are found in deep pools such as are uncovered at low spring 

 tides. Another deep water red seaweed characteristic of the warm 



