716 MINNESOTA BOTANICAL STUDIES. 
Arthrocardia ? frondescens (Post. et Rupr.) Aresch. in J. Ag. 
Spec. cule, ll, sp o540, 
i maxima, tf. nov. “Pl: LIL, Pig. 3. 
Fronde majore et crassiore ; articulis pinnarum lobis latissimis 
saepe crenulatis, apicalium compressis obovatis vel spatulatis. 
f. intermedia, ¢. nov. jPl asi, Pie. 2: 
Fronde tenuiore; articulis pinnarum compressis deltoideo- 
obcordatis lobis nonnunquam acutis. 
f. polymorpha, f. nov.. Pl. LI.,'Fig.4; Pl. LVL, Pigsaie 
6a and 7. 
Fronde minore; crassiuscula, polymorpha: tum articulis pin- 
narum obcordatis, obreniformibus vel sagittatis, apicalium obo- 
vatis vel globosis; tum articulis pinnarum axiumque cylindra- 
ceis, linearibus vel globosis. 
Ruprecht’s illustrations and description 7. c. precisely coincide 
with f. tyfzca. Areschoug remarked in J. Ag. Spec. Alg. Z. c. 
that the original plant might have been a tiny form of the spe- 
cies. We have at Port Renfrew plants often attaining to several 
centimeters in height. 
f. ¢ypica is a densely cespitose plant, irregularly pinnated ; 
the lowermost pinnz attain to the length of the main stem, and 
thus give the appearance of trichotomy. The articuli are com- 
pactly arranged, the lower margin of an articulus in contact 
with the upper margin of the subsequent one. Conceptacles 
are mostly found two to four in number and placed on the 
shaded surface, often, however, solitarily immersed at the 
angles of a deltoid articulus. 
f. max7ma is distinguished from the other forme by its large 
and compressed articuli at the upper portion of the branches. 
These articuli measure 2-5 mm. broad, 1.5-2 mm. long and 
are often cleft at their lobes. The branches are not so dense as 
in f. ¢ypzca. 
f. zntermedza is characterized by having the upper portions of 
the fronds revoluted downwards while it is yet young. The 
articuli are rather less wide than those of f. ¢yfzca and in every 
partthin. The lobes of the articuli are angled and consequently 
more loosely arranged. 
f. polymorpha attains to a length of scarcely one inch and 
has its articuli thick and rough. Its form is very variable, some- 
times assuming quite an aberrant appearance (Pl. LVI., Fig. 6, 
