ri
E.Mve ic.mct.ols UHF
P l a t e CCCXX.
POLYSIPHONIA SPINULOSA, Grev.
Gen. C h a r . Frond filamentous, partially or generally a rticu la te ; joints
longitudinally striate, composed of numerous radiating cells or tubes
disposed round a central cavity. Fructification twofold, on different
individuals: 1, ovate capsules [ceramidia] furnished with a terminal
pore, and containing a tu ft of pear-shaped spores; 2, tetraspores
imbedded in swollen branchlets. P o l y s i p h o n ia [Grev.),— horn noXw,
many, and a tube.
P o l y s i p h o n ia spinulosa ; “ dark red ; branches divaricate, somewhat rigid,
the ramuli short, straight, subulate, divaricate ; articulations about
equal in length and breadth, three-tnbed; tubercles” (young ceramidia)
“ globose, sessile, excessively minute.” Orev. I. c.
P o l y s i p h o n i a spinulosa, Grev. Scot. Crypt. FI. t. 90. Harv. in Hooh. Br. FI.
vol.ii. p. 330. Harv. Man. ed. 2. p. 84.
H ab . “ Sea-shores” (probably in tide-pools) at k-ÿffia. Captain Carmichael.
Very rare.
G b o g r . D i s t r . ?
D e s c b . “ Frond 1-2 inches in length, of a dark red colour, much branched,
with a rigid and spinulose habit ; main branches rather remote, irregular,
much divaricated, somewhat flexuous ; ultimate ramuli straight, subulate,
almost thorn-like, divaricated like the rest, sometimes minutely divided at
the apex, and each of the divisions terminated in a long, hyaline, jointed
filament. Articulations about as long as broad, striated with three internal
tubes of a pale brown-pink under the microscope. Tubercles very minute,
quite sessile, round, dark red, scattered freely on the branches, and containing
several dark granules.”— Gre». I. c. A transverse section of the
stem (fig. 5) shows four primary siphons of large size, with secondary and
tertiary cells at the angles. In drying, the plant adheres to paper.
One of our rarest species, only found by Captain Carmichael,
and by him only once, and now figured from a specimen preserved
in the Hookerian Herbarium. The resemblance between
P . spinulosa and our P. Carmichaeliana is great, but P. spinulosa
is a much smaller and more delicate plant, and its stems arc
articulated throughout.