266 Floristik, Geographie, Systematik etc. 



tany. Part I: Introduction. The Sea-grasses of West 

 Australia. (Dansk ßotan. Arkiv. IL N» 6. 44 pp. 31 figs. 1916.) 



In the autumn of 1914 the author visited West Australia in 

 response to an invitation from the British Association for the Ad- 

 vancement of Science. He spent most of his time in the south- 

 western part of the State, and when leaving it by steamer, called 

 at some ports of the tropical part. The present paper is the first 

 of a series intended to publish the botanical results of the visit. 



The name „sea-grasses" is used to designate the Flowering 

 Plants which live in sea water and are unable to exist in fresh or 

 nearly fresh water. The sea-grasses of W. Australia are: Cymo- 

 docea angustata nov. sp., C. antarctica (Labeil.) Endl., C. isoetifolia 

 Aschers., Diplanthera uninervis (Forsk.) Aschers., Posidcnia austra- 

 lis J. D. Hook, Halophüa ovalis (R. Br.) J. D. Hook, and H. spinu- 

 losa (R. Br.) Aschers. The record of C. rotundata Aschers, from 

 West Australia is doubtful, as it probably Covers the new spe- 

 cies C. angustata. 



The morphology, structure and biology of five of the mentioned 

 species are dealt with in detail. 



Cymodea angustata of which only female plants were found, 

 was discovered at Carnarvon, Sharks Bay; it is near to C. ro- 

 tundata and C. serrulata. 



In C. isoetifolia both male and female plants were found; it is 

 compared with the allied C. inanatorum of the West In dies, and 

 it is shown that most of the reputed differences do not hold good, 

 the only reliable character being the number of nerves in the leaves. 



The Singular vivipary of C. antarctica discovered by Tepper 

 and further studied by I. M. Black, is reexamined and corrobo- 

 rated. The explanation given by P. Ascherson reducing the phe- 

 nomenon to a vegetative bud-production , is quite wrong. It is 

 really the seed which germinates in the fruits, and not until the 

 seedling is far developed, does it loosen and float, with the peri- 

 carp still adhering as a kind of anchor. I. M. Black, who has 

 separated the plant from the other Cyjnodocea^s and created the 

 new genus Pectinella, has divided it into two species, but the pre- 

 sent author retains it in the old genus and admits only one species. 



Posidonia australis has a fruit biology which comes near to 

 that known for the mediterranean P. oceanica. The fieshy fruit 

 floats for a time owing to air in the exocarp; then the „stone", i. e. 

 the seed covered by the membranous endocarp, drops out and 

 sinks to the bottom. The author happened to see the sea near 

 the coast covered by thousands of opened fruits and found the shore 

 fringed by a belt of the same material. Besides the true P. austra- 

 lis, sterile leaves of another form were found, their structure diffe- 

 ring in many respects from the leaves of the type, but asnorhizoms 

 nor flowers were found, it has not got any specific name. 



Of the rare Halophila spinulosa the male flowers were nearly 

 unknown, their morphology and biology are described, as well as 

 the morphology and structure of the very peculiar leaves. 



C. H. Ostenfeld. 



Rietz, G. E. Du, Nägra synpunkter pä den synekologiska 

 vegetationsbeskrifningens terminologi och metodik. 

 [Einige Gesichtpunkte für die Terminologie und 

 Methodik der synökologischen Vegetationsbeschrei- 



