308 Transactions. — Botany. 



round the interior of the bladder wall. Fig. 3 is a transverse 

 section through the external tissues of the stern. 



Reproduction by zoogonidia, produced in clavate sporangia 

 on the basal leaves. Fig. 4 is a transverse section through a 

 fertile portion of the frond. The sporangia, however, are much 

 more densely crowded together than there represented. 



Distribution, everywhere abundant, forming a fringe round 

 the coast ; rhizoid fixed below low water-mark. 



10. D' Urvillea utilis. 



Generic description in " Handbook of New Zealand Flora :" 

 " Eoot scutate. Frond stalked, dark olive-brown or black, flat, 

 expanded, very thick and coriaceous, or honeycombed trans- 

 versely internally, palmate or pinnate without distinct organs. 

 Fruit dioecious, conceptacles scattered over the whole frond in 

 the cortical stratum, containing either obovoid subsessile spores 

 or branched filaments bearing ovoid antheridia." (Sp. ) " Frond 

 dark-brown or black, often 30 feet long, forming an immense 

 flabellate palmately-lobed laciniated lamina contracted at the 

 cuneiform base into short stipes as thick as the wrist, segments 

 or thongs often 1 inch thick, honeycombed internally." 



The epidermal cells of this plant are much larger than in 

 most brown seaweeds. The central tissue is composed of longi- 

 tudinal fibres, which occasionally anastomose. 



Eejn'oduction : The plant is dioecious. The conceptacles 

 have not a fringe of hairs surrounding the aperture, as in Fucus 

 platycarpxis, and many other Fucacea. The reproductive organs 

 may be found almost at any season of the year, but they are 

 best obtained in tbe winter months. It is stated in Hooker's 

 Handbook (vide ante) that the spores (oospheres) are subsessile. 

 This may be the case in young conceptacles ; but in the maturer 

 ones the oospheres are developed on branched hairs. Fig. 5 

 represents one of these branched hairs, bearing several empty 

 and one mature oogonium, with a tripartite oosphere. This is 

 an important exception to the rule that unbranched hairs alone 

 are found in the female conceptacles. Fig. 5, a, b, c. show the 

 method of division of the oosphere. 



At low tide, on a warm moist winter's day, many of the 

 fronds of V Urvillea, if examined, are seen to be covered with 

 hundreds of little dark-brown almost black papillae, consisting 

 solely of oospheres expelled from the conceptacle. The antheridia 

 do not collect outside the conceptacle in such numbers as the 

 oospheres, but they occasionally form whitish dots covering the 

 surface of the frond. The antheridia are developed in the usual 

 way on branched hairs. 



Hab. Common about low tide-mark, on exposed rocks. 



11. Notheia anomala. 



Description in Hooker's Handbook (generic) : "Frond, olive- 



