1888. | BOTANICAL GAZETTE. 203 
PLATE xvi. Webera camptotrachela.—a, entire plant; b b, leaves; ¢, 
areolation of the middle; d d, external perichetial leaves; e, inner peri- 
cheetial leaf; f, capsule with the lid; g g, capsule deoperculate ; h. portion 
of the external peristome ; 7, portion of the inner peristome. 
ditt 
mune; ¢ e, capsule of P. Ohioense; f, capsule of 
xvul. Fontinalis Howellii.—a, entire plant; b b, upper stem- 
leaves; cc, branch-leaves; d, perichetial leaf; e, capsule ; f, portion of the 
external peristome ; g, portion of the lattice-cone. : 
LATE } Fontinalis flaccida.—a a, leaves; b 6, point of same; ¢, 
areolation of an auricle; d, areolation of the middle. 
ATE Xx. Camptothecium Amesix.—a, entire plant; ), branch-leaf ; 
¢, areolation of the base of same; d, perichetial leaves; ¢ ¢, capsule wi 
pedicel; f, portion of the outer and inner peristome. 
‘ 
Zygomorphy and its causes. Il. 
CHARLES ROBERTSON. 
As soon as a shallow flower becomes horizontal the in- 
sect relations change, and certain modifications which would 
be corrected in vertical flowers become advantageous. While 
sect, is now limited to the under side. It will be gree 
hectaries, the bee must turn and hang under the grvevieed is 
very inconvenient operation which causes delay. 1S 
i? The bees menti i were named by Mr. E, T. Cresson. 
8 Bor, Gaz. 1X. a in this paper 3 
8 
