Ser. Chloeospeeme,®. Fam. Oscillatoriea.
P l a t e CCCXV.
RIVULARIA PLICATA, Cam.
G e n . C h a r . Frond g l o b o s e o r l o b e d , f le s h y , f i rm , c o m p o s e d o f c o n t i n u o u s ,
r a d i a t i n g f i l a m e n t s , a n n u l a t e d w i t h i n a n d s p r i n g i n g f r o m a s p h e r i c a l
g l o b u l e , a n d s u r r o u n d e d b y , o r s e t i n , g e l a t in e . E i v t j l a u i a [Both),
— i n a l l u s i o n t o t h e f lu v i a t i l e h a b i t a t o f s o m e o f t h e s p e c i e s .
l l iv u L A E iA p lic a ta ; f r o n d s r a t h e r l a r g e , d e n s e l y g r e g a r i o u s , g e l a t in o u s ,
o o m p r e s s o - p l i c a t e , o f t e n h o l lo w a n d a t l e n g t h r u p t u r e d , d a r k g r e e n ;
f i l a m e n t s w a v y , a s s o c i a t e d i n d i c h o t o m o u s s e r i e s , t a p e r i n g t o a f in e
p o i n t .
R iv u l a m a plicata, Oarm. Harv. in Hook. Br. FI. vol. ii. p. 892. Harv. Man.
ed. 2. p. 222.
L i c h e n corrugatus, Dickson ! (fide Borrer).
H ab. On the rocky sea-shore, about high-water mark, or in situations only
occasionally overflowed by salt water. Appin, Capt. Carmichael.
Ballintrae, Ayrshire, Mr. W. Thompson. Eyrmouth, Dr. Johnstone.
Torbay, Mrs. Griffiths. Innischerig Island, Malbay; and elsewhere,
W.H.H.
Geooe . D istk . ?
D esoe. Fronds densely crowded together, each patch generally occupying a
surface of several square inches; variously lobed, and by mutual pressure
distorted and compressed, so that the mass has a plaited or warted appearance.
When young the fronds are solid and firmly gelatinous; as they
advance in age they become hollow, and are at length often ruptured and
variously torn. Fllaments wavy and much attenuated, associated in dichotomous
or subdichotomous series, each filament being joined to its fellow
hy a spherical, pellucid connecting cell, and the whole firmly set in the gelatinous
matrix of the frond. Rings evident and close. Colour a dark,
lurid, or blackish green. Substance elastic, smooth, and somewhat lubricous.
In drying, the plant shrinks considerably, and if subjected to pressure will
adhere firmly to paper.
A well-marked species of Bimlaria, easily recognized and not
uncommon on several parts of our shores. It was first noticed
by the late Captain Carmichael on the west coast of Scotland.
Like B. nitida, it becomes hollow in age, but may always be
known from that species by its much darker and duller colour,
smaller size, and, the difference of habitat. The frontU are very
irregular in shape, and alter considerably as they advance to
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