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



39 



they may be referred to the larger variety which is called Lem- 

 nopsis major by H. Zollinger (Verzeich, der im indisch. Archipel 

 in den Jahren 1842 — 48 gesamm. etc. Pflanzen (1854) 

 74; quoted from Ascherson (1867) 172). 



The species seems to vary very much with 

 regard to the size and shape of the leaves, and 

 perhaps some of the more divergent forms are 

 really independent species. But until flowering and 

 fruiting specimens are found in greater abundance 

 than hitherto, it is better to follow Ascherson 

 (1867, 200), who united H. oralis, H. madagascar- 

 iensis Steud., H. major (Zoll.) Miq., H. lemnopsis 

 Miq. (= Lemnopsis minor Zoll.) into one species. 

 With regard to H. ovata Gaudichaud (1. c), I have 

 elsewhere (Ostenfeld, in Philippine Journ. of Sc, 

 IV No. 1, Sect. C. Botany, 1909, 67) shown that 

 it is a good species, at present only known from the 

 Philippines and Mariannes. 



The morphology of H. ovalis has been thoroughly 

 investigated by I. B. Balfour (1879), and later the 

 structure of the leaves was studied by C. Sauvageau 

 (Journ. de Botanique IV, 1890, 293). 



Quite recently H. Solereder 1 has examined 

 the structure of the leaves of H. ovalis and other 

 species, and has found some interesting features 

 which were overlooked by the earlier authors : The 

 central area of the outer walls of the epidermal 

 cells is thinner than the remaining parts, and when 

 seen from above, a circular spot is more or less 

 distinctly visible. This observation I can corrob- Yx h^' 0V aiis°' 

 orate after examination of my West Australian from Yallingup 

 material of H. ovalis. Solereder's other discovery 



Cave District. 

 Transverse sec- 

 is not quite so convincing: The leaves consist tion of_ part of 



only of the two epidermal layers except where 



a leaf. The black 

 dots are the 



traversed by the veins. Between these two layers veins (the big 

 Solereder found, singly or a few together, some ^J^ln^^hé 

 idioblasts which he calls '•Schlauchzellen". My circles the air 

 material showed here and there smaller cells he- 

 tween the two epidermal layers, but they did 



chambers. 

 (About *% nat. 



size). 



*) H. Solf.reder: Systematisch-anatomische Untersuchung des Blattes 

 der Hydrocharitaceen. — Beih. Botan. Centralbl., Bd. XXX. 1. Abt. 

 1913, pp. 24-104. 



