A Synopsis of Plant Phyla 3 



opinion more commonly held that plants came from animals over 

 practically the same pathway. 



In the preparation of this Synopsis the limitations of families 

 as given in Engler and Prantl's "Natiirlichen Pflanzenfamilien" 

 have been followed in general, especially m the higher phyla. 

 The departures from this rule occur chiefly in the Zygophyceae 

 where the "tribes" of desmids and diatoms have been raised to 

 the rank of families. To the writer the added clearness and ease 

 of comprehension of these groups of plants have proved valid 

 reasons for these innovations. In all cases the brief descriptions 

 which accompany the names of classes, orders and families, are 

 intended to be suggestive of relationship, rather than differential 

 diagnoses. The genera cited in each family are intended to help 

 the reader more easily to recognize the type represented by the 

 family. The citation of the ''Pflanzenfamilien" (Pf.) with vol- 

 ume, part (abteilung), and page are for the purpose of making 

 that great work more quickly accessible where a reference to it 

 is desirable. In a very- few cases the fifth edition of Engier's 

 "Syllabus der Pflanzenfamilien" is cited, where new families have 

 been proposed since the appearance of the larger work. 



In this paper the whole number of families included is 636, 

 disposed as follows : 



Phylum Myxophyccae 9 Phylum Pteridophyta 13 



" Bryophyta 54 



It remains only to say that while the phyla are taken up in 

 their proper sequence, as here understood, and that under these 

 the classes and orders are arranged in accordance with the un- 

 derlying theory, it has not been possible in all cases to carry out 

 this plan in the arrangement of the families in the orders. In 

 the great majority of orders those families which appear to be 

 more primitive are placed at or near the beginning of the group, 



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