Olosterium truncatum, Breb. Meneg. Syn. Desm. (1840), p.
235.
Pleurotmnium truncatum, D. By. Conj. (1858), p. 104. Delponte
Desm. (1878), t. 19, f. 7-11. Oleve Sver. Desm. (1864),
p. 494. Nordstedt Norges Desm. (1873), p. 47. Rabb. Alg.
Eur. (1868), p. 142. Wille Nov. Sem. (1879), p. 57. Nordsted
t Desm. Spitz. (1872), p. 26. Lundell Desm. Sueo.
(1871), p . 89.
H ab. In pools.
Sussex, Surrey, Cornwall, W a le s; France, Germany, Italy,
Norway, Sweden, Nova Zembla, United States.
Plate V I., fig. 4. a, living c e ll; h, empty cell.
D o c id ium B a c u lum . Preb. in Ralfs. Desm. (1848), p. 158, t. 33, f. 5.
Segments very slender, having a solitary and conspicuous
inflation a t the base, otherwise lin e a r; vesicles in a single
series.
Siz e . 14-22 ^ diam. (W.) ; 0-46-0-6 mm. x 15 „ (D.) :
14-22;. (K.). VK ) ,
Kirch. Alg. Schles. (1878), 144. Archer in P rit. Inf.
(1861), p. 745, t. 3, f. 38. Nordstedt Norges Desm. (1873),
p. 46. P e tit Liste Desm. Paris (1877), p. 29. Wittrock
Scan. Desm. (1869), p. 21. Jacobsen Desm. Denm. (1874),
p. 179. Wolle Desm. U.S. (1884), p. 49, t. 11, f. 3, 4. Breb.
.-liste Desm. (1866), p. 147.
Olosterium sceptrum, Kutz. Phy. Germ. (1846), p. 133,
Olosterium baculum, Breb. Alg. Eal. (1835), p. 69, t. 8.
Olosterium trabeculoides, Corda Aim. Oarls. (1840), t. 6,
f. 44.
Pleurotcenium baculum, D. By. Conj. (1858), p. 75
Delponte Desm. (1878), p. 130, t. 20, f. 12-16. Cleve Sver.
Desm. (1864), p. 494. Wood E. Wate r Alg® U.S. (1872),
p. 119. Rabh. Alg. Eur. (1868), p. 141.
H ab. In ponds.
Sussex, Gloucester, Lancashire, Westmoreland, Yorkshire,
Cornwall, Wales, Scotland; France, Germany, Denmark,
Norway, Italy, Sweden, United States.
P late V II., fig. 4. a b , living cells; e d, empty cells.
D o c id ium m in u tu m . Ralfs. Desm. (1848),y). 158, t. 2 6 ,/. 5.
_ Frond slender, slightly constricted a t the middle, segments
linear, not inflated, vesicles in a single series.
S iz e . 7-9 p or 10-12 p diam. (W.).
Archer in P rit. Inf. (1861), p. 745. Brebisson Liste Desm.
(1856), p. 148. Notaris Desm. Ital. (1867), p. 57, t. 5, f. 57.
Jacobsen Desm. Denm. (1874), p. 179. "Wolle Desm. U.S.
(1884), p . 52, t. 60, f. 29-31, t. 10, f. 9.
PeniMm minutum, Cleve Sver. Desm (1864) p. 493^^ Lundell
Desm. Suec. (1871), p. 87. RabK Alg. Eur. (1868) p
122. Wood E. Wate r Alg® U.S. (1872), p. 107. Nordstedt
Norges Desm. (1873), p. 45. + 90 f
Pleurotcenium minutum^ Delponte Desm. (io 7 o j, t. i.
17-21
Penium Balfsii, De Bary Conj. (1858), p. 73, t. 5, f. 8.
H ab. In ponds.
Hants, Sussex, Wales; France, Germany, United States,
Italy, Sweden.
Plate V I I I ; fig. 1. a b c, living cells; d, empty cell.
D o c id ium h i i s u tu m . Pail. Micr. Obs. (1850), t. 1, / . 8.
Frond ra th e r slender, suture not prominent, segments four
to six times as long as broad, not tapering, inflation obsolete,
ends entire, surface all over minutely spinous or hirsute.
S iz e. 23-30 m diam. (W.).
Archer Prit. Inf. (1861), p. 745. Archer in Quart. Journ.
Mior. Sci. (1879), xix., p. 438. Rabh. Alg. Eur. (1868), p.
145. Wolle Desm. U.S. (1884), p. 51, t. 10, f. 13 ( p .
Pleurotcenium hirsutum, Wood F. W a te r Alg® U.S. (1872),
p. 121.
H ab. In sluggish waters.
Ire la n d ; United States.
Very much resembling a species of Gonatozygon.
Plate V I I ; fig. 5. «, living c e ll; b, empty cell.
Gbntjs 8. C L O S T E R IUM . NitscTi. (1817).
Frond elongated, attenuated, more or less Innately curved
or arcuate, entire, not constricted a t th e middle, the junction
of th e segments marked by a pale transverse hand.
Endochrome often arranged in longitudinal fillets, and at
each extremity having a terminal clear space, in which are
active g ran u le s; empty frond smooth or with longitudinal
stri®, never granulated.—Archer in Pritch. Inf. 746.
* Frond scarcely tapering, curvature slight, gradual, and
equal, lower margin nearly straight, or slightly concave, ends
truncate or broadly rounded.
C lo s te z ium d id ym o to c um . Corda Aim. Carls. (1835), t. 5 ,/ . 64, 65.
Frond stout, six to ten times longer th an broad, nearly
straight, very slightly tapering to the ex tremitie s; upper
margin slightly convex, lower nearly stra ig h t or very slightly
concave, sometimes slightly inclined upwards a t th e end,
2
M il'l
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