256 BULLETIN OF THE BUREAU OF FISHERIES. 



Further contribution to the present status of the Potamogetons incorporates of 

 necessity a considerable body of observation pertaining to the systematic, morpho- 

 logical, and biological aspects of this group, and renders it highly desirable to set forth 

 the historical background of each of these three phases of the subject. 



John Gerarde. 1633. 



A beginning in the classification of the Potamogetons was made by the old herbalists, medical 

 men, who found it necessary to study plants in detail in order to discriminate the kinds employed for 

 different purposes. The special virtue in Potamogetons, for example, resided in the leaves, which 

 were applied to reduce inflammation. In the herbal of John Gerarde the group Potamogeton {Pota- 

 mogcilon in the old spelling and pondweed or water spike in the common parlance of the time) con- 

 sisted of four species — a broad-leaved pondweed, a narrow-leaved pondweed, a small pondweed, and 

 a long sharp-leaved pondweed. There was a figure of the entire plant accompanied by tJie Latin and 

 English name. Then followed the "description, place, time, names, nature, and virtues agreeing 

 with the best received opinions." A "fennel-leaved water milfoile" illustrated by a figure easily 

 recognized as our fennel-leaved pondweed, Potamogeton pectinatus, was given a place among the 

 Myriophyllums. Such was one of the earliest attempts to classify the group. 



Chamisso and Schlechtendal, 1827. 



The first important monograph of the Potamogetons was the work of Chamisso and Schlechtendal, 

 who, in Linnea, volume 2, 1827, systematized the results of scientific observation during tlie latter 

 part of the eighteenth and the beginning of the nineteenth centuries. Under the family name of 

 Alismaceae 21 species were described and illustrated by drawings of fruit and leaf, including among 

 them many of the common and widely distributed species of to-day. Several other Potamogetons 

 were listed as uncertain in position and difficult to classify, a condition which holds as true to-day as 

 then, when Chamisso and Schlechtendal struggled to bring order out of chaos in this puzzling group 

 and recorded this pertinent observation: "Species Potamogetonum habitum mutantes in alias ssepe 

 transire videntur, aliensque speciei habitum mentientes scrutatorum irrident," which translated 

 is, " Species of Potamogeton changing their habit seem often to pass into others, and feigning the habit 

 of other species baffle research." 



Reichenbach, 1845. 



Reichenbach's monograph of the Potamogetons, in his Icones Flora; Germanicse et Helvetics, 

 followed in 1845. More intensive in scope than any preceding work, it marked a distinct advance 

 both in the method of description and in the matter of illustration. Several reproductions, especially 

 of flower and fruit, which were drawn with great clearness and accuracy, have found their way in the 

 latest authoritative works on the subject. In this monograph the author introduced the figure of the 

 so-called "bur," the vegetative propagative body of P. crispus Linnseus, though he apparently did 

 not recognize its significance in the rapid propagation of this species. It is interesting to note that 

 the figure is inserted without further description or comment. Moreover, it is erroneously drawn, and 

 the error h;is been copied time without end. 



Irmisch, 1851. 



Thilo Irmisch, in a published note in Flora, 1851, first recognized the presence of tubers on P. 

 pectinatus. 



Agardh, 1852. 



A year later J. C. Agardh, in Verhandlungen der K. Schwedischen Akademie der VVissenschaften, 

 recorded several observations on the tubers of this species of Potamogeton. 



Clos, D., 1856. 



D. Clos w'as the first to publish an account of the origin of tlie "bur" of crispus, tliough his obser- 

 vations are incomplete regarding both their development and their germination. 



Irmisch, 1858. 



In a remarkable monograph by Irmisch, Ul^cr cinige Arten aus der naturlicheii Pflanzcnfamilie der 

 Potamogeton, the history of the development of the tuberous growths on /^. />t'C/!Ha/H.f is recorded and 

 their morphological and anatomical structure described. The autlior states tliat, at the end of Uie vegeta- 



