C. H.Ostenfeld: Contributions to West Australian Botany. I. 9 



with white naked patches between. So far as I could discover, 

 the vegetation nearly always consists of sea-grasses, the detached 

 leaves and shoots of which were common on the surface of 

 the water near the jetty. Along the shore there was a fringe 

 of washed-up material consisting almost entirely of sea-grasses, 

 with very few pieces of algæ intermixed. The main bulk was 

 leaves of Posidonia, of which some fruits and empty pericarps 

 were seen; in addition there was abundance of Cymodocea 

 isoetifolia, Cym. angustata nov. sp., some Cym. antarctica and 

 Halopkila spinulosa, and a few pieces of Halophila ovalis and 

 Diplanthera un inervis. 



From this list of species of the shore fringe, it is probable 

 that the sea-grass vegetation of the bottom consists mainly of 

 Posidonia with the Cymodoceæ, Halophilæ and Diplanthera as 

 subordinate elements. 

 Sharks Bay in particular must produce enormous quantities 

 of sea-grasses, as such wide areas are suitable for their growth, 

 and I was told that nearly the whole Bay had a green bottom. 

 Other places suitable for sea-grass vegetation are: 



4. King George's Sound. During my short visit to Albany there 

 was no time to investigate the sea-grass vegetation, but we 

 have the earlier records by Harvey, who tells about the oc- 

 currence of large meadows of Cymod. antarctica and Posidonia. 



5. Flinders Bay. 



6. Geographe Bay. 



7. Rottnest Island, where Harvey dredged and found sea-grasses. 



8. The Abrolhos Island to the west of Geraldton (Champion Bay). 



On the whole, all places where there is a little shelter will 

 most probably be found to bear a sea-grass vegetation, while on 

 the other hand the open and quite unprotected coast will be 

 devoid of them, unless they find a refuge in shallow pools 

 amongst rocks, as was the case on the coast off Yallingup (see 

 above). 



The depth to which the sea-grass vegetation of W. A. extends, 

 is not known. We have only the records of 2 to 6 feet ( 2 / 3 — 2 m) 

 by Harvey and of 7 fathoms (c, 13 m) by Naumann. 



No doubt the limit lies somewhat deeper than the two records, 

 and investigations on this point are highly desirable. 



