BIBLIOGRAPHY 393 



Pearsall, W. H. The Aquatic and Marsh Vegetation of Esthwaite 



(1917-1918) Water. Journ. of Ecology, Vol. v. 1917, pp. 180-202 



[p. 288] and Vol. vr. 1918, pp. 53-74, 12 text-figs. 



(A detailed ecological survey of a Lancashire lake.) 



Pearsall, W. H. (1918) On the classification of Aquatic Plant Communities. 

 [p. 288] Journ. of Ecology, Vol. vi. 1918, pp. 75-83. 



(The author regards aquatic, fen and moor successions as 

 together forming a unit and leading up to the one formation 

 moor.) 



Perrot, . (1900) Sur les organes appendiculaires des feuilles de 



[p. 169 and Fig. no, certains Myriophyllum. Journ. de Bot. T. xiv. 1900, 

 p. 170] pp. 198-202, 5 text-figs. 



(An account of the peculiar processes borne by the leaf of 

 Myriophyllum verticillatum and M . spicatum, which the author 

 regards as pluricellular caducous trichomes.) 



Pfeiffer, L. (1854) Ueber einige deutsche Nymphaen. Bot. Zeit. Jahrg. 

 12, 1854, pp. 172-175. 



(A critical article in which special stress is laid on the import- 

 ance for systematic purposes of ascertaining the characters of 

 the ripe fruit.) 



Pieters, A. J. (1894) The Plants of Lake St Clair. Bull. Michigan Fish 

 [p. 288] Commission, No. 2, 1894, 12 pp., i map. 



[An ecological study in which the zonation of the plants 

 observed in Lake St Clair is compared with that recorded by 

 Magnin, A. (1893) for the Jura lakes.] 



Pieters, A. J. (1902) Contributions to the Biology of the Great Lakes. 

 [p. 291] The Plants of Western Lake Erie, with Observations 



on their Distribution. Bull. United States Fish 

 Commission, Vol. xxi. 1902 (for 1901), pp. 57-79. 

 10 pis., 9 text-figs. 

 (An ecological study.) 



Planchon, J.E. (1844) Observations sur le genre Aponogeton et sur ses 

 [p. 314] affinites naturelles. Ann. d. sci. nat. Ser. in. Bot. 



T. i. 1844, pp. 107-120, i pi. 



(The author describes Aponogeton distachyus and brings 

 forward evidence for removing it from the neighbourhood cf 

 Saururus and placing it in a sub-order between the Alismaceae 

 and Juncaginaceae.) 



Planchon, J.E. (1853) fitudes sur les Nymph6acees. Ann. des sci. nat. 

 Ser. in. T. xix. 1853, pp. 17-63- 

 (A systematic account of this family.) 



Pond, R. H. (1905) Contributions to the Biology of the Great Lakes. 

 [p. 264] The Biological Relation of Aquatic Plants to the 



Substratum. University of Michigan. Inaug. Diss. 

 Ann Arbor, 1905, 43 pp., 6 text-figs. 

 (This paper contains important experimental work relating to 

 the function of the roots in aquatic plants.) 



