x CONTENTS. 
TroricaL NortH AMERICAN Spgcizs or Panicum. By A. 8. Hitchcock and * 
Agnes Chase..........0... 022002200 cece cece nec cc nec cee ec ceeeeeceececeee 459 
Introduction........ 2.0.0.0... cece eee ee cee cece ec cece eeecceeccee 459 
Key to species and groups......... 2.222.000.0220 e cece cence cece cceeee 460 
Annotated list of the species.................. wee eee eee eee eee ee --. 463 
Excluded species. ...... 2.22.22... 22. c eee eee cece eee e cece ee cececceee 532 
List of new species............ 0.2.22. .c cee cece cee cee cence e eee eee 539 
Stuptes or Tropica, AMERICAN FgernNs—No. 6. By William R. Maxon..... 541 
Introduction........ 22.0... 22.0 eee c cece eee cee cee cece eeeeceeceeee 541 
Polypodium trichomanoides and its American allies......................-. 542 
Polypodium furfuraceum and related species... ....................---. 557 
Polypodium squametum and its allies.............000...0000ee cece cece eee 579 
New species of Polypodium. . ................00.. 00022 c eee ccee cece eee 597 
Notes on Notholaena.......... 22.0000... 00002 c eee cece ce cece cece. 601 
Miscellaneous notes. ............2.22. 0002000 ce cece eee eee ceceeececeuee 607 
BRANCHING AND FLowertna Hasits or Cacao AND PaTAsHTE By O. Ff 
0) 609 
Introduction..... 2.2.0.0... 2.02. c ccc eee e eee eee ceceeeceeseees 609 
Morphological and ecological comparisons...............--.2..2-.22-2--- 611 
Dimorphism of branches................0.0 00.000. c cece eee e ese ee eee 611 
Practical significance of dimorphic branches. wee eee eee cece eens 612 
Numbers of lateral branches. ........ 2.2.00... 000000 ce cece cece eee. 612 
Arrangement of leaves on branches................0.02-02-00-00000-0- 613 
Dimorphism of leaves. .....-.2...... 00000 c cece cee cece cece ec eeeee 613 
Measurements of petioles and leaf blades........................-.-. 614 
Venation of leaves...... 02.2.2... 000000020 o ce eee ec ee ee cece 616 
Positions of inflorescences. ................. wobec eee eee eee eee eee 616 
Periods of flowering........ wn ee eee eee erent eee acne c cece eens 617 
Structure of inflorescences......... 2.22.02... cee cececeececcecceeeee 617 
Structure of flowers........... 220.0200. 000 e cece cece eee ce cee ceeeee 618 
Floral adaptations. ......... 2.220.020.0002. 0 cece cece eee eceeceecee 619 
Question of nativity... 2.2.2.2. eee eee cece ce eee 622 
Ecological significance of different habits..................0..2.-00-- 622 
Lateral branches considered as inflorescences. ..........2222.00e-eee- 623 
Descriptions of the genera. ....... 2.222222. ee cee cee cee ccceeecceceeecees 624 
INDEX... 2... eee ee ce nee ee cee ee cee cue ecu teccccccccceee 627 
