visible to the eye (of an oval or oblong form) are often abortive ; but
the scattered seeds are distinctly visible under the microscope, lying
beneath the epidermis, and slightly prominent.
3. P u n c t a r ia t e n u is s im a .
Frond sublinear, very thin, transparent.
Sonaría ? tenuissima, Ag . S y s t. A lg . p . 268.
Sona ría ? plantaginea v . tenuior, A g . S p . A lg . v . 1. p . 138.
Ulva plantaginifolia v . tenuior, L y n g b . H y d r o p h . D a n . p . 31. t . 6.
H a b . in the sea, parasitic on Zosiera marina. Annual. Summer.
Common on the coasts of the Isle of Bute.
Root a very minute disk. Fronds aggregated, often forming a thick
fringe on the leaves of Zostera marina, two to eight inches in length,
and one to three lines in width, always attenuated at the base, but
either attenuated at the extremity or abruptly terminated and rounded,
the margin entire or somewhat denticulate, waved or even. Fructification
unknown. Substance exceedingly thin and transparent, highly
and beautifully reticulated, slightly lubricous, adhering to paper in drying.
Colour a very pale transparent yellowish or reddish green, becoming
slightly darker when dried.
In this delicate species the fructification has not been observed. I
have indeed noticed a minute thickening in the substance of the frond
here and there, accompanied with an opacity sufficiently indicative of
fructification ; but in no case have I seen the seeds developed. The
reticulated structure is very striking and beautiful.
Alga. It differs from the preceding genus, in its tubular and branched
frond, and in the uniformly transverse disposition of the groups of
seeds, which to the naked eye appear as lines. From the following
one, it differs in the last named character, and the more highly reticulated
structure.
I. S t r ia r ia a t t e n u a t a . Tab. IX.
Striaria attenuata, G r e v . C r y p t . F I . (S y n o p s is ) p . 44.
Carmichaelia attenuaia, G r e v . C r y p t . F I . t . 288.
H a b . In the sea, on various Algæ. Annual. Summer. Appm,
Captain Carmichael. Shores of the Isle of Bute.
Root a very minute disk. Frond three to twelve inches in height,
less than a line in diameter, attenuated at each extremity, much
branched, the branches patent, elongated, mostly opposite, sometimes
set with a second series, all much attenuated at their origin and extremity.
Fructification circular prominent groups of roundish seeds
(occasionally mixed with a few short obtuse filaments), disposed in
transverse lines hardly more than a quarter of a line asunder. Substance
tender and membranaceous, adhering to paper in drying.
Colour pale olivaceous green, changing when dry to a yellower hue.
The duration of this species seems to be short ; as it prefers attaching
itself to the more delicate Algæ, such as the upper branches of the
Polysiphoniæ, Rhodomela subfusca, &c.: and I have seldom seen a
specimen uninjured, in consequence of its tender substance. Hitherto
it has only been observed on the western coast of Scotland.
i
' -
!
G e n u s XVI. STR IAR IA, Grev. Tab. IX.
G e n . C h a r . Frond filiform, tubular, continuous, membranaceous,
branched. Root naked and scutate. Fructification
groups of roundish seeds forming transverse lines.
O b s . The name I first bestowed upon this plant in the Cryptogamic
Flora, was that of Carmichaelia, to commemorate a very industrious
botanist in this department. Captain Carmichael. I find, however, the
same appellation has been bestowed upon a genus of Leguminose plants
a short time before, and have therefore substituted Striaria for the
2
G e n u s X V II. DICTYOSIPHON, Grev. Tab. V III.
G e n . C h a r . Frond filiform, tubular, continuous, branched.
Root minutely scutate, naked. Fructification, ovate,
scattered seeds lying beneath the epidermis.
O bs. It was my wish to have formed a single genus of this and the
preceding plant; and perhaps farther observation may discover reason for
their union. At present, however, the difference in fructification, the
exceedingly branched frond, the branches quite capillary, and not attenuated
at their origin, and the different substance of the plant before
us, induce me to keep them asunder.