48-50. Nordstedt Desm. Arct. (1875'), p. 33, 39. Kirch. Alg.
Schles. (1878), p. 165. Cleve Sver. Desm. (1864), p. 491.
Lundell Desm. Suec. (1871), p. 63. Grunow Desm. Austr.
(1858), p. 498. Wittrock Scan. Desm. (1869), p. 19. Brebisson
Liste Desm. (1856), p. 140. Schaarschm. Magy. Desm.
(1883), p. 270. Mask. New Zeal. Desm. (1882), p. 243.
Wood P. Water Alg® U.S. (1872), p. 150. Nordstedt Desm.
Spitz. (1872), p. 38. Lemaire Desm. Vosg. (1883), p. 23.
Wolle Desm. U.S. (1884), p. 126, t. 41, f. 36-38.
Staurastrum dilatatum c. tricorne, Rabh. Alg. Eur. (1868), p.
207.
Binatella tricornis, Breb. Alg. Fal. (1835), p. 57, t. 8.
Desmidium hexaceros, Ehr. Infus. (1838), p. 141, t. 10, f. 10.
Phycastrum tricorne, Kutz. Phy. Germ. (1845), p. 137.
Phycastrum trilobatum, Kutz. Spec. (1849), p. 179.
Phycastrum hexaceros, Kutz. Spec. (1849), p. 180.
Phycastrum Ralfsii, Niig. Einz. Alg. (1849), p. 125.
Phycastrum crenulatum, Niig. Einz. Alg. (1849), t. 8, b, in
part.
H ab. In ponds and pools.
Sussex, Westmoreland, Cornwall, Wales; France, Germany,
United States, Spitzbergen, Sweden, Nova Zembla, Hungary,
Italy, Austria, New Zealand.
Plate L V I I I . , fig. 2. a, living frond; b, empty frond; c d, end
views.
var. 0. Ra lfs Lesm. (1848),p. 134, t. 34, f . 3 ,b c d.
Processes terminated by minute spines.
Wittrock Scan. Desm. (1869), p. 19. Lundell Desm. Suec.
(1871), p. 63.
H ab. In ponds.
Sussex, Cornwall.
Plate L X I V ; fig. 5. a, living frond ; b, empty frond ; c if, end views ;
e, zygospore.
Stauza stzum cy z to c e zum . Breb. in R a lfs Lesm. (1848), p. 139, t.
22, f . 10.
Frond rough with minute granules; segments in front view
somewhat triangular with short incurved processes. Zygospore
orbicular, spiny ; spines slightly forked at the apex.
Siz e. Length 31 p ; diam. 33 p (W.) ; length 23 p ; diam.
33 p (N.).
Wolle Desm. U.S. (1884), p. 128, t. 42, f. 30, 31. Archer
in Prit. Inf. (1861), p. 742. Nordstedt. Norges Desm. (1873),
p. 83. Brebisson Liste Desm. (1856), p. 139. Jacobsen Desm.
Denm. (1874), p. 206. Wittrock Sotv. Alg. (1872), p. 51.
Phycastrum cyrtocerum, Kutz. Spec. (1849), p. 180.
Staurastrum polymorphum var. cyrtocerum. Wood F. Water
Alg® U.S. (1872), p. 151. Eabh. Alg. Eur. (1868), p. 209.
H ab. In ponds.
Gloucestershire, Sussex, Cornwall, Wales ; France, Norway,
Sweden, Denmark, United States.
Plate L V I I I . , fig. 3. a, living frond; b, empty frond; c ó, end
views.
S tauzastzum a z cu a tum . Nordst. Norges Lesm. (1873), p . 3 6 ,/. 18.
Rather small, about one-third broader than long, constriction
deep, expanding; segments elliptic, divergent (obversely
lunate) angles furnished with short geminate divergent spines,
on the upper surface at each side a pair of intermediate sliort
bifid spines, surface granulate, granules in transverse lines ; end
view triradiate, sides concave.
Siz e . Length 20 p ; diam. 29 p (N.).
Archer in Journ. Bot. iii. (1874), p. 92. Wolle Desm. U.S.
(1884), p. 139, t. 46, f. 13, 14, var.
H ab. In mountain pools.
Ireland ; Norway, United States.
Plate L I., fig. 2. a, living frond ; b, empty frond ■, e d e, end views.
S tauza stzum in fie x um . (Breb.) Fritch. Infius. (186Í), p. 742.
Segments in front view broadly elliptic, inner and outer
margin turgid, rough with minute granules, lateral proc/ses
incurved, short, divided at the apex ; end view three or four-
radiate, processes short, sides concave.
Siz e . Length 35 g ; diam., with arms, 45 p.
Lemaire Desm. Vosg. (1883), p. 23. Cooke in Journ.
Quekett Club (1880), t. 16, f. 88.
H ab. In pools.
Lake District, North Wales; France.
p la te L V I I I . , fig. 5. a, living frond ; b b, empty fronds ; c d, end
views.
S tau za stzum p olymozphum. Breb. in Ralfs. Lesm. (1848), p. 135,
Í. 2 2 / . 9; Í. 3 4 ,/. 6.
Segments rough with minute granules, having on each
side a short process tipped with spines; end view three to
six-rayed. Zygospore orbicular, spiny ; spines few, forked
a t the apex.
S ize. Length 45-53 p ; diam. 53 / (N.) ; length 21-35 p ;
Í1 -ri