R 1VULARIA Opuntia.
Indian-fig Rivularia.
CRYPTOGAMIA Algte.
G e n . C h a r . Frond gelatinous, firm, destitute of an
external cuticle. Fructification among jointed filaments,
lodged in the substance of the frond.
S p e c . C h a r . Compressed, branched, red, jointed ; joints
elliptical, confluent. Jnternalfilamentsrepeatedlyfork-
ed ; their ultimate joints shortened, filled with seeds.
S y n . Fucus Opuntia. Gooden, and TVoodw. I r . o f L.
Soc. v. 3. 2 19 . Turn. Syn. 387. Hull. 3 2 6 .
F. repens. L ightf. 961. W ith. v. 4. 91.
Ulva articulata /3. Huds. 569.
Tremella marina cæspitosa, segmentis tenuibus. Dill.
Muse. 50. t. 10. ƒ . 9.
R E C E I V E D b y fa v o u r o f M r . T u r n e r from H a s t in g s , S u s s e x .
I t g r o w s o n e x p o s e d m a r in e r o c k s , a lw a y s , a c c o rd in g to that
g e n t lem a n , b e tw e e n h ig h - a n d lo w -w a t e r m a r k s , fo rm in g
sm a ll c r e e p in g tu f t s . T h e fr o n d s a re e n ta n g le d , m u c h b r a n c h e
d , c om p r e s s e d , s o lid , o r a t le a s t n o t , l ik e Fucus articulatus,
t. 1 5 7 4 , tu b u la r . A t ra n s v e r s e s e c t io n u n d e r th e m ic ro s c o p e
s h o w s th e ir in te rn a l s p o n g y su b s ta n c e to b e a c o n g e r ie s o f h o r
i z o n t a l , r e p e a ted ly fo r k e d , jo in t e d filam e n t s , w h o s e in n um e r
a b le , g r a d u a lly sh o r t e r , u lt im a te jo in t s , fu l l o f red ju i c e , w h ile
th e p r im a r y o n e s a re lo n g e r a n d c o lo u r le s s , m e e t a t th e su rfa ce
o f th e f r o n d , an d g iv e it a d o t ted a s p e c t . I t s c u r io u s s tru c tu re
w a s fir s t d is c o v e r e d b y M r . J . D . S o w e r b y , a n d le a d s u s to
r e fe r th e p la n t to Rivularia, se e t. 1 8 1 8 , T h e e x c e lle n t
w r ite r s in Linn. Trans, v. 3 , h a v e so n e a r ly a p p ro a ch ed this
d is c o v e r y as to in fo rm u s th a t “ th e u p p e rm o s t jo in t s p erfo rm
th e o ffic e o f tu b e r c le s (w ith r e sp e c t to Fuci in g en e ra l) and
a re p r e g n a n t w i th e x t r em e ly m in u t e c row d e d s e e d s .” W h e t
h e r th e s e se ed s b e m o r e n um e ro u s , o r m o r e p e r fe c t , in the
la te r a l w a r t s , o b s e r v a b le in o u r s p e c im e n o n s om e o f th e u p p
e r jo in t s , o n e o f w h ic h is c u t a c ro s s in o u r m a g n ifie d s e c t io n ,
w e c a n n o t a c c u r a t e ly s a y .
W e m u s t r em a rk th a t Fucus Wigghii, t. 1 1 6 5 , p ro v e s on
m o r e a c c u r a t e e x am in a t io n to b e a t ru e Rivularia, th e a c c o u n t
o f its se eds h i th e r to g iv e n b e in g in c o r r e c t .