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Holm: Recherches ariatomiqnes et morphologiques sur deux mono- 

 cotylédones submergées (Halophila Baillonii Aschs. et Elodea densa 

 Gasp.); Bih. till k. Svenska Vet.-Akad. Handl. Bd. 9, No. 13, 1885). 



Halophila decipiens Ostf. ; nat. size. 



The Expedition has brought home a large material of this new Halo- 

 phila, as well flowering as fruitbearing specimens preserved in alcohol. 

 It resembles very much the Westindian H. Baillonis. I have examined 

 for comparison a very large alcohol material of the latter (amongst other 

 the same specimens as Mr. Theo. Holm has used for his above men- 

 tioned carefull treatise), and I have found but a slight difference between 

 this and the new species; the main difference consists in the absence of 

 the short hairs on the ventral surfaces of the leaves in the new species, 

 while H. Baillonis has short hairs on both sides. If the geographical 

 distribution was not so quite different, I should prefer to regard it as a 

 variety of H. Baillonis, but it is not probable to suppose such a connection 

 as the sea-phanerogams generally have very natural and limited areas and 

 H. Baillonis is confined to the shores of the Westindian Archipelago. 



From H. ovalis which is common along the shores of the Indian 

 Ocean, the new species is very different; the monoecious flowers, the small 

 teeth in the margins and the short hairs on the surfaces of the leaves, 

 the few lateral veins etc. remove it far from this. 



Off Koh Kahdat, in 5 fathoms water (coral-sand). 



Lemnaceæ. 



Lemna L. 



4. L. paucicostata Hegelm., Die Lemnaceen, 1868, p. 139; Hook, f., 

 Fl. of British India VI, p. 556. 



Only sterile specimens have been collected. 

 Koh Kong, in a pool. 



Area: Tropical Africa, Asia, Australia and Polynesia; (tropical America?). 



