172 THE SCOTTISH BOTANICAL REVIEW 



and called Hydrocharites ohovatus is of doubtful affinity. The genus 

 is found at the present day in Europe and North Asia. 



Ottelia inhabits the mouths of rivers, e.g. the Nile, Ganges, and 

 rivers in Australia. The leaves are cordate and the plant is practi- 

 cally stemless. The flowers are hermaphrodite, being situated on a 

 scape and enclosed by a spathe. The flowers possess 6-12 stamens, 

 and 6 stigmas. The berry contains 6-8 cells with many seeds. 



Brongniart gave to a fossil from the Eocene of Paris the name of 

 Fotamogeton multinervis. It had oval petiolated leaves. The veins 

 were numerous and longitudinally connected by reticulations. 

 Saporta, however, renamed this fossil Ottelia parisie?nis, and draws 

 a comparison between it and O. ulvcefortnis, Pers., a native of 

 Madagascar. Other fossils have been referred to Ottelia also. 



The genus Hydrilla is closely aUied to Anacharis. It is an 

 aquatic plant with whorls of sessile leaves, and a slender stem. Like 

 Ottelia It is found in rivers in India, China, and America. The 

 single flowers are in axillary spathes. The perianth is reflexed and 

 six-cleft. It possesses three stamens which become detached and 

 float upon the water. Like Vallisneria, the female flower has a long 

 threadlike stem, and the stigma thus comes to the surface and is 

 fertilised by the male flowers. Heer describes a fossil under the 

 name Naias stylosa, from the Swiss Tertiaries, which may perhaps be 

 a Hydrilla. 



111. GlUMIFLOR/E. 

 ix. Graminece. 



Many fossils have been wrongly ascribed to grasses. Those 

 familiar with Lindley and Hutton's " Fossil Flora '" will recall the 

 Poacites cocoina} which is really part of the leaf of a species of 

 Cordaites. The unsatisfactory nature of characters based on leaf- 

 form, unless also supplemented by structural evidence, makes it 

 practically impossible to place such fossils in existing genera. 



Specimens based on spikes or flowers have been named Oryza 

 exasperata by Heer, and specimens from the Tertiary of Switzerland 

 have also been referred to Fa?iicum, L., and to Palaopyrum, 

 Schmalh, from the Eocene of Kiew. 



Like the equisetaceous fossil plants, called Calamites by Suckow 

 and originally held to be fossil reeds, many fossils have been referred 

 to Bambusium, which have no true resemblance whatever to the 

 recent Bambusa. 



Such are Bambusa bohetiiica, Ett., and B. 7niocenicum, Ett., from 

 Bilin., and B. neocomense, Heer, from the Miocene of Fribourg, is 

 probably cycadean. 



The comparatively recent Bambusa lugdunensis., Sap., of the 

 Middle Pliocene, Meximieux is, however, more satisfactory, the 

 leaf-characters recalling those of a living Asiatic species. 



The Festuceae are represented in European and North American 



1 " Fossil Flora," p. 169, vol. ii., pi. 142, B. 



