410 TUFTS COLLEGE STUDIES, VOL. II, No. 3 



but with the note that too much stress should not be laid on 

 them, except as indicating special lines or limits of variation. 

 A short characterization of all the sections is given below, but 

 three sections are not yet represented in North America : Sect. 

 4, Zosteroideae, Africa and Spain ; Sects. 7 and 10, Hippuroideae 

 and Araucarioideae, Australia. 



SECTIONS OF CAULERPA. 



I. Stolon and erect fronds filiform, without differentiated raniuli. 



T. VAUCHERIOIDEAE. 



II. Stolon cylindrical and creeping; erect fronds of distinct |form. 

 Stolon naked or with simple or bifid hairs ; fronds slender, bearing 



near the summit whorled ramuli. 2. CHAROIDEAE. 



Stolon with hairs or ramuli; frond of a moss-like aspect, surrounded 

 by more or less branching ramuli. 3. BRYOIDEAE. 



Stolon naked ; fronds elongate in the form of a Zostera leaf, flat or 

 cylindrical, simple or dichotomous ; margin entire, without 

 ramuli. 4- ZOSTEROIDEAE. 



Stolon naked ; fronds flat, margin entire or slightly serrate, little 

 branched, but often producing proliferously from the lamina 

 similar secondary laminae. 5. PHYLLANTOIDEAE. 



Stolon naked ; fronds flat, deeply dentate, serrate or pinnate, rarely 

 cylindrical, and then surrounded by pinnules several times 

 as long as the diameter of the axis. 6. FILICOIDEAE. 



Stolon naked or with scattered ramuli; fronds simple or branched, 

 surrounded by three or more ranks of imbricate spreading or 

 erect ramuli ; ramuli sometimes short, usually long, simple, 

 forked, or pinnate. 7. HIPPUROIDEAE. 



Stolon covered with woolly hairs or simple ramuli ; fronds cylindrical , 

 simple or branched, surrounded by very densely set simple 

 or bifid raniuli. 8. LYCOPODIOIDEAE. 



Stolon naked; fronds generally robust, but sometimes slender, fas- 

 tigiate, cylindrical, surrounded by cylindrical, ovoid or 

 pyramidal ramuli, distichous, tristichous or multiseriate ; 

 or sometimes plane and linear with edges entire, dentate or 

 serrate, twisted or not. 9. THUYOIDEAE. 



Stolon covered with four-parted scales ; fronds resembling an Arau- 

 caria, with branches distichous, sub-opposite or alternate, 

 covered with simple or bifid, mucronate ramuli. 



10. ARAUCARIOIDEAE. 



Stolon naked ; frond of a primary naked, simple or dichotomous 

 axis, bearing at its summit simple or dichotomous secondary 

 axes, bearing pinnate ramuli. Pinnules usually unilateral, 

 turned upwards, simple or pinnate, mucronate. 



ii. PASPALOIDEAE. 



