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* 9 
NOTES ON LEMNACEA AND ON THE DISCOVERY OF 
THE RAPHIDIAN CHARACTER IN SYSTEMATIC BO- 
TANY. 
By Georer GurLrvEm, F.R.S 
Although our knowledge of the comparative structure of the Duck- 
weeds has been much advanced during the last few years, we do not 
find a corresponding progress in the descriptions and figures of these 
plants in our books of systematic botany. The forthcoming plate of 
Wolfia, under the care of the worthy editor of the third edition of 
‘English Botany,’ will, no doubt, be at least on a level with the pre- 
sent state of science. As yet there have been added in that work only 
the flowers of Lemna polyrrhiza to the old plates of the four species of 
this genus; while those important details of structure which are now, 
through the memoirs by Hoffmann and others, well known as affording 
valuable diagnostic characters, are not figured, and the large vacant 
space of each plate is left waste and useless. And hence, for a satis- 
factory exposition of our own familiar and useful Duckweeds, we are 
still obliged to consult, besides our great national Flora, the engravings 
and descriptions scattered through various foreign and native periodi- 
cal works, most of which have been so carefully specified in Dr. Trimen’s 
valuable paper on Wolfia, published in a former volume of this Jour- 
nal, as to relieve me of the task of citations. 
In short, a fair account of the British Lemnacee is now wanting in 
our books, and the present notes are intended as a small contribution 
towards this desirable object, which involves a few little additions to, 
and a revision of, some points respecting these plants and raphides 
in the sixty-fourth number of the third edition of * English Botany.’ 
Use of Duckweeds.—As the popular and practical English mind is 
wont to raise this question at the threshold, * English Botany’ is ready 
there with its answer :—“ Although pretty enough to excite general 
interest, we have nothing to record of the uses of the species of Lemna.” 
Too severe a sentence, surely, on even these abject and despised things 
and withal in sad disregard of that plea for the Duckweeds, long since 
advanced in the case of L. minor, which d the utility of one or other 
f these ly mean and worthless plants i in the economy of nature. 
For di it is that the most common and abundant Duckweed may be 
found, and recognized by its cell-characters, in the stomachs of young 
