394 Griggs : Characters of the Platanaceae 



of conjecture. Such shortening might be expected to favor the 

 development of perigyny but the flowers are clearly hypogynous 



I \ 



(figs. I, 2, 5) and have no perigynous disc as Schoenland main- 

 tains. The -presence of staminodes and of rudimentary carpels 

 seems to indicate clearly that the flowers were originally perfect. 

 The homology of the scale encircling the pedicel is somewhat 



doubtful. It may be the vestige of the calyx. But its form sug- 



gests strongly the sheathing base of a foliage leaf. If it is to be 

 compared with a leaf it would represent a vestigial bract surround- 

 ing the' pedicel as the bases of the leaves surround the buds 

 in their axils. But it is so much reduced that it is not possible 

 in my judgment to determine with certainty what it represents. 



Whether this represents a bract or a calyx, it is clear that 

 Platamis is apetalous and that it should be removed- from the 

 Rosales and placed among the Apetalae. In this group the place 

 of the Platanales is probably to be found next the Urticales. 

 This position they originally held on account of their obvious 

 resemblances to some of the Urticales. There seem to be in this 

 case no characters of the life history which are more significant 

 than those general similarities that every observer recognizes, 

 namely : the tendency toward the aggregation of the flowers into 

 spherical heads by the shortening of the pedicels, which has been 

 carried to its culmination in Platanus and such genera of the 

 Urticales as Artocarpus and Toxylon, and the development of 

 sheathing stipules completely encircling the stem and covering, 

 the bud as In Artocarpus and Fiais. . Between these genera and 

 Platanus there is of course a gap so wide as to be of ordinal rank, 

 and yet these similarities may indicate the approximate place of 

 the Platanales among the orders of the Apetalae and save it from 

 complete isolation. 



Ohio State University, 



Columbus, Ohio. 



Literature cited 



J. Niedenzu, F. Platanaceae, in Engler & Prantl, Pflanzenfamihen 



3'': 135-^0- 1891. 

 2. Robinson, B. L., & Fernald, M. L. Gray's New manual of botany, 



454- 1908- 



