1863.] BOTANICAL INTELLIGBNCB. 469 



species. The spikes are short, lax ; fruit with a shghtly curved 

 beak, which is about as long as the fruit. A very common species, 

 both in deep and shallow water. 



12. P. se/raius, Hudson, is by some descriptive authors entered 

 as a variety of P. crispus, and by others as more fitly belonging 

 to P. densus. Smith's description of P. crispus agrees better 

 with this variety than it does Avith the common form. He be- 

 sides tells us, that Clusius' figures, Pan. 713, f. 714, 715, in 

 Johnson's emaculate (not immaculate) edition of Gerard's ' Her- 

 bal ' is annexed to a description of P. densus ! 



P. serratus has lanceolate, serrated, sometimes crisp leaves, not 

 above two inches long, oblong-lanceolate or lanceolate. It is not 

 an uncommon form. 



P. densus, Linn. Stem cylindrical, rather stout, more or less 

 branched, very leafy. Leaves opposite, ovate-lanceolate, sessile, 

 entii'e, pellucid, all submerged. Peduncles slender, short ; spikes 

 few-flowered ; fruit compressed, with a short terminal beak and 

 a prominent keel. Not rare in the south of England. 



Note. It is hoped that during the ensuing season materials 

 may be collected or contributed to furnish forth the second part 

 of this monograph. 



BOTANICAL INTELLIGENCE. 

 " Society of Amateur Botanists." 



A circular with the above-written heading has been recently 

 sent to our office, and we gladly embrace this earliest opportunity 

 of trying to promote its circulation. 



Co-operation, or the principle of associated efforts, in the ad- 

 vancement of knowledge, has always been strenuously advocated 

 in our pages ; and we have several times proposed the Natural 

 History Societies in Glasgow, Todmorden, and Warrington as 

 models which might be imitated with success, especially in Lon- 

 don, which is the metropolis of science as well as the emporium 

 of commercial business. 



This new candidate for scientific reputation is confessedly a 

 great desideratum, an institution much wanted. Its location is 

 239, Euston Road. As our readers may not be profoundly read or 

 learned in the modern geography and nomenclature of the streets 



