Griggs : Characters of the Platanaceae 395 



3. Gleason, H. A. Platanaceae, in N. Atn. FL 22 : 227-229. 1908. 



4. Gray, A. Manual of botany, 446. 1867. [5th edition], 



5. Sargent, C. S. Manual of the trees of North America, 343. 1905. 

 6. -. Silva 7 ; 99-104. pi. J26, J895. 



» « 



7. Schoenland, S. Ul^er die Entwickelung der Bluten und Frucht 

 bei den Platanen. Bot. Jahrb. 4: 308-327. 1883. 



Hxplanatioti of plate 2S 



The figures are caaiera drawings of microtome sections, r, carpel ; (?, outgrowth 

 from receptacle of staminate flower = vestigial carpel; J, staminode ; sc, encircling 



scale ; j/, stamen. 



Fig. I. Portion of a median section of a staminate head, showing one flower with 



parts of two others at the sides, X ^5* October 3. 



Fig. 2. Longitudinal section of a staminate flower, showing outgrowths from the 

 receptacle, which are doubtfully homologiz.ed with carpels, X^S- April 25. 



Fig. 3. Cross section through the filaments of a flower of the same age as fig. 2, 



X6S. 



Fig. 4. Tangential section through the pedicels of a staminate inflorescence of 



same age as figs. 2 and 3, X ^S- 



Fig. 5. Longitudinal section of a group of carpellate flowers, X ^S' January 15. 



Fig, 6, Tangential section of a carpellate head, X 65. April 18. 



Fig. 7. Similar section at the level of the encircling scale, X^S- April 18. 



