vi 
CONTENTS OF VOLUME XXIfI [JUNE 
BRIEFER ARTICLES—continued 
A new Isoetes from Idaho . i 3 F . . L. #. Henderson 124 
Definiteness of variation and its significance in taxonomy /. 4. Waugh 193 
Algze exsiccatae . i ‘a : - : Veit Wittrock 196 
Algze in the solfatara at Pozzuoli, Italy : J. Y. Bergen 1098 
Facilities for botanical research at the se cans eile Station. Plate 
: Z 4 r Walter T. Swingle 278 
poidie ternatum var. Nelaeeees : . George E. Davenport 282 
Seed crests and myrmecophilous dissemination in certain plants 
Charles Robertson 288 
tabi urceolatum, a new eure re parasite of Selaginella 
rupestris. Plate XXIx . , . . Mary E. Olson 367 
The preparation of material for aes ea use . Geo. F. Atkinson 372 
Curious leaves [with text cuts]. 6 ee Re Se ere. 468 
EDITORIALS— 
Equipment for physiology : . : . . : cages 
Tropical laboratory commission ‘ ives ‘ - Raais ae 
Foreign Associate Editors ae ioe i ging ratien . : et 
The metric system in ent . Moose ‘ me oe ‘ a 
