38 Dansk Botanisk Arkiv, Bd. 2. Nr. 6. 



Fam. II. Hydrocharitaceae. 



Two species of Halophila are found in the sea off the West 

 Australian coast; both of them also occur on the East coast of 

 the continent. They differ considerably from each other in 

 external appearance and both are quite unlike the ordinary 

 ribbon-leaved type of sea-grasses. 



1. Halophila ovalis (R. Br.) J. D. Hooker, 

 Flora Tasman. II (1860) 45; Ascherson, in Linnæa 35 (1867) 173; Bentham, 

 Fl. Austral. VII (1878) 182; I. B. Balfour, in Transact. & Proc. Roy. Soc. 

 Edinburgh XIII (1879) 290; H. ovata F. v. Muller, Fragm. Phytogr. Austr. 

 VIII (1872—74) 219; Second Census Austr. PI. (1889) 193, et aliis; non 

 Gaudichaud, in Freycinet Voy. Bot. (1826) 430, tab. 40, fig. 1; Caulinia? 

 ovalis R. Brown, Prodr. Fl. Nov. Holland. (1810) 339. 



As already stated (p. 7) this species was first recorded for 

 West Australia by C. Andrews (1. c, 1902), who found it in 

 Freshwater Bay, Swan River Estuary in 1902 (Fl. of W. Austr., 

 No. 1065), and shortly after it was discovered on the coast of 

 Rottnest Island, off Fremantle (by Markwell). I collected a 

 small piece of it cast ashore at Geraldton (No. 272) and found 

 it growing plentifully in pools on the coast off the Yallingup 

 Gave (No. 273). As to the latter record my diary contains the 

 following remarks: "Halophila ovalis inhabited mostly the smaller 

 pools. It often grows so deeply imbedded in the sand, that only 

 the leaf-blades are visible, and in this case the leaves are long- 

 stalked and the shoot-apex with the young leaves is quite hidden, 

 pale-yellow and etiolated. No flower was found". The leaf blades 

 were 24 — 27 mm long, 10—12 mm broad, and the stalk attained 

 to 40 — 45 mm long. 



The four localities now known are all along the southern 

 part of the west coast of West Australia, and seem to indicate 

 a common occurrence of the species. 



H. ovalis is widely distributed along the coast of the Indian 

 and Pacific Oceans, and has the widest area of occurrence of all 

 the Halophila species. Around Australia it is known from West 

 Australia, South Australia, Tasmania, Victoria, New South Wales 

 and Queensland, and, probably it occurs on all parts of the 

 coast where the conditions permit it to grow. 



The specimens collected and also all the other specimens 

 seen from Australia are rather uniform: vigorous and robust 

 with long and large leaves (the blades are 25—50 mm long); 



