Klebs. Desm, Pmss. (1879), p. 24. Nordstedt Noijes Desm.
(1873), p. 43. Petit Liste Desm. Pans (1877), p. 28. Wood
k Wat. Alg® U.S. (1872), p. 109. Rabh. Alg. Ear. (1868),
p 121. Wolle Desm. U.S. (1884), p. 35, t. 5, f. 18. Kirch.
Alg. Schles. (1878), p. 135.
Closterium lens, var. intermedia, Jacobsen Desm. Denm.
(1874), p. 167.
H ab. In ponds.
Sussex, Surrey, Hants, Cornwall, Wales, Ireland ; France,
Germany, Italy, Sweden, Norway, United States.
Flate X V I ., fig. 3. a, living frond ; h i, empty fronds.
F e n iu m N a g e lii. (Breb.) Pritch. Infus., p. 751.
Frond large, stout, smooth, about four times longer than
broad, oblong, not contracted at the middle, gradua ly tapering
to each extremity, sides nearly straight, ends broadly truncate,
endochrome arranged in interrupted divided planes radiating
from the central axis, in front view being indented somewhat in
a pinnatified manner, the rays touching the cell wall, soinetimes
divided, and somewhat dilated thereat, in transverse view radiate.
Siz e . Length 160 p ; diam. 34 p.
Nordstedt Norges Desm. (1873), p. Petit Liste Desm.
Paris (1877), p. 27. Rabh. Alg. Eur. (1868), P- 1 ^ .
Closterium (Netrium) digitus. Nag. Emz. Alg. (p. 108), t.
6 ,D.
H ab. In ponds, &c.
Ireland ; France, Germany, Norway.
Plate X V I ., fig. 4.
a a, living frond ; b, empty fro n d ; c, transverse
section.
F e n iu m n a v i c u l a . Breb. Liste Lesm., t. 2 ,/. 37.
Frond minute, about three or four times as long as broad,
smooth, fusiform, ends bluntly pointed ; endochrome sometimes
scattered, interrupted only by the transverse central pale band,
with one or two large granules in each half, and a rounded deal
space at the end, in which are active granules. Zygospore sub-
quadrate, compressed, with rather acute angles.
Siz e . Diam. 12-11 p (W .); length 43-72 /x; diam. 12-
17 u ; zygospore 33-38 X 38-43 p (K.-)-
Archer in Prit. Inf. (1861), p. 751. LundeH Desm. Snec.
(1871), p. 84. Nordstedt Norges Desm. (1878), p. 43. Notaris.
Desm. Ital. (1867), p. 68, t. 8, f. 77. Rabh. Alg. Eur.
(1868), p. 121. Wolle Desm. U.S. (1884), p. 36, t. 5, f. 16.
Closterium lens, var. minor, Jacobsen Desm. Denm. 1874),
p. 168.
Penium Berginii, Archer Nat. Hist. Rev.
Penium closterioides b navicula, Klebs. Desm. Pruss. (1879),
p. 24.
H ab. In ponds, &c.
Ireland, Cornwall; France, Germany, Sweden, Norway, Italy,
United States.
Plate X V I ,,fig . S. aa, living fronds; 6 b, empty fronds.
F e n iu m B ie b is s o n ii. Ralfs. Lesm., 153, t. 25, / . 6.
Frond smooth, cylindrical with rounded ends, transverse
central band inconspicuoiis, zygospore at first quadrate, finally
orbicular, conjugating fronds persistent.
Size. Diam. 16-17 p (W.) ; diam. 15-30 /lx (K.).
Wood F. W. Alg® U.S. (1872), p. 108. Brebisson Liste
Desm. (1856), p. 147. Rabh. Alg. Eur. (1868), p. 120. De
Bary Conjug. (1858), p. 74, t. 7, E. Lundell Desm. Suec.
(1871), p. 83. Nordstedt Norges Desm. (1873), p. 43.
Nordstedt Desm. Arct. (1875), 14, 37, 39. Petit Liste Desm.
Paris (1877), p. 27. Wille Nov. Sem. (1879), p. 55.
Jacobsen Desm. Denm. (1874), p. 165. Nordstedt Desm.
Spitz. (1872), p. 25. Wolle Desm. U.S. (1884), p. 36, t. 5,
f. 7, 8. Kirch. Alg. Schles. (1878), p. 136.
Penium Brehissonii a. typicum. Klebs. Desm. Pruss. (1879),
p. 23.
Palmella cylindrospora, Brebisson Alg. Pal. (1835), p. 64.
Cylindrocystis Brehissonii, Meneg. Nost. (1841), p. 89, t.
12, f. 3.
H ab. In pools, &c.
Widely distributed in Great Britain ; Sweden, Germany,
France, Spitzbergen, Nova Zembla, Russian Lapland, Norway,
United States, New Zealand.
var. C. J e u n e z i . {Ralfs.) Kirch. Alg. Schles., p. 136.
Zygospore orbicular, conjugating fronds deciduous.
Siz e . Length 40 p ; diam. 14-18/x (K.).
Brebisson Liste Desm. (1856), p. 147. Wood F. W. Alg®
(1872), p. 108. Rabh. Alg. Eur. (1868), p. 120. Wolle
Desm. U.S., p. 36.
Penium Jenneri, Ralfs. Desm. (1848), p. 153, t. 33, f. 2.
Plate X V I I . , fig. 3. a b, living fronds j c, empty frond; d, young
zygospore ; e, ripe zygospore.
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