VI. Segments without spines, end view angles rounded,
f Frond smootli.
S tauzastzum m u ticum . Breb. in Meneg. Syn. Besm. (1840).
Segments smooth, elliptic ; end view showing slightly concave
sides, and three to five rounded angles. Zygospore orbicular,
spiny ; spines robust, cleft at their apices.
Siz e . Length 35-40 p.; diam. 3 3-40/x (N.) ; diam. 33-38 p.
(Wo.).
Ealfs Desm. (1848), p. 125, t. 21, f. 4 ; t. 34, f. 13. Archer
in Prit. Inf. (1861), p. 740. Nordstedt. Desm. Arct. (1875),
p. 32. Wille Norges Desm., p. 40. Cleve Sver. Desm. ^ 8 6 4 ),
p. 489. Lundell Desm. Suec. (1871), p. 56. Petit Liste
Desm. Paris (1877), p. 31. Grunow Desm. Austr. (1858), p.
501. Wittrock Scan. Desm. (1869), p. 16. Wood P. Water
Algse U.S. (1872), p. 148. Notaris Desm. Ital. (1867), p. 55,
t. 5, f. 53. Rabh. Alg. Eur. (1868), p. 200. Schaarschm.
Magy. Desm. (1883), p. 270. Brebisson Liste Desm. (1856),
p. 144, Nordstedt. Desm. Spitz. (1872), p. 38. Jacobsen.
Desm. Denm. (1874), p. 202 partly. Lemaire Desm. Vosg.
(1883), p. 23. Wolle Desm. U.S. (1884), p. 119, t. 39, f.
11-15.
Phycastrum muticum, Kutz. Spec, Alg. (1849), 178.
Staurastrum trilobum, Meneg. Consp. Alg. (1837), p. 18.
Binatella muticum, Breb. Alg. Fal. (1835), p. 57, t. 8.
Phycastrum depressum. Nag. Einz. Alg. (1849), p. 126, t. 8
A., f. 1.
H ab. In ponds.
Westmoreland, Cornwall, Wales ; France, Germany, Sweden,
Norway, Denmark, Spitzbergen, Austria, Hungary, Italy,
United States.
Blate L I ., fig. 6. a, living frond ; b, empty frond ■, c d e, end views.
S tauzastzum o zb icu la z e . R alfs. Ann. Nat. Hist. (1845), xv., p .
152, 1 .10.
Segments smooth, semi-orbicular ; end view bluntly triangular.
Zygospore orbicular, beset with subulate spines.
Siz e. Length 28 p ; diam. 25 p (D.) ; diam. 30-45 p (Wo.) ;
diam. 22-50 p (K.). Length 82 p ; diam. 27 u (N.).
Ealfs Desm. (1848), p. 125, t. 21, f. 5. Archerin Prit. Inf.
(1861), p. 740. Wille Norges Desm., p. 40. Delponte Desm.
(1878), t. 10, f. 5-12 partly. Nordst. Desm. Arct. (1875), p.
32. Wittr. Sotv. Alg., p. 54. Cleve Sver. D(^sm, (1864), p.
489. Kirchn. Alg. Schles. (1878), p. 164. Lundell Desm.
Suec. (1871), p. 56. Nordstedt Norges Desm. (1873), p. 26.
Petit Liste Desm. Paris (1877), p. 31. Grunow Desm. Austr.
(1858), p. 498, 502. N o rd s t.* Wittr. Desm. Ital. ( / 7 6 ) ,
p. 42. Schaarschm. Magy. Desm. (1883), p. 272. Wittrock
Scan. Desm. (1869), p. 16. WoodF. Water Algæ U.S. (1872),
p. 148. Brebisson Liste Desm. (1856), p. 144. Notaris
Desm. Ital. (1867), p. 55, t. 5, f. 53. Eabh, Alg. Eur.
(1868), p. 200. Wille Nov. Sem. (1879), p. 49. Jacobsen
Desm. Denm. (1874), p. 202. Lemaire Desm. Vosg. (1883),
p. 23. Nordst. Desm Bras. (1869), p. 224. Wolle Desm.
U.S. (1884), p. 120, t. 39, f. 9-10.
Desmidium orbiculare, Ehr. Abh. Berl. Ak. (1 832), p. 282.
Ehr. Inf. (1838), p. 141, t. 10, f. 9.
Phycastrum orbiculare, Kutz. Phy. Germ. (1845), p. 137.
Goniocystis ( Trigonocystes) orbicularis, Hass. Fr. Alg. (1845),
p. 349.
H a b . In ponds.
Sussex, Kent, Hants, West Yorkshire, Westmoreland, Cornwall,
Wales, Scotland ; France, Germany, Sweden, Norway,
Denmark, Spitzbergen, Nova Zembla, Austria, Hungary, Italy,
Brazil, United States.
Plate L I ., fig. 7. a a, living fronda ; b c, empty fronds -, d e f , end
views ; g, zygospore.
var. 0. c x t e n s u m . Nordst. Norges Lesm., p. 26, f . 10.
S iz e . Length 46-48 p ; diam. 33-36 p (N.).
H a b . In gelatinous coating of rocks.
Scotland.
S ta u z a s tz um p y gm æ um . B r e b . i n R a l f s Lesm.{18‘tö ),p .2 1 3 ,t.3 5 ,
f. 26.
Segments in front view cuneiform, outer margin slightly convex,
smooth, end view with three blunt angles, sides slightly
convex. Zygospore orbicular, beset with protuberances, bearing
each two bifurcate spines at their summits.
Siz e . Length 82-34 p] diam. 27-34 p (Witt.), 40 x 38 ^
(N.).
Archer in Pritch. Infus. (1861), p. 740. Wittr. Sotv. Alg,
(1872), p. 53, t. 4, f. 10. Nordst. Norges Desm. (1878), p
29. Wille Norges Desm. (1880), p. 42. Wille Nova Sem
(1879), p. 51. Nordst. Desm Arct. (1873), p. 34. Nordst
Desm. Gronl. (1885), p. 10. Wolle Desm. U.S. (1884), p,
125, t. 42, f. 14-21.
H a b . In pools.
France, Germany, Norway, Nova Zembla, Greenland, United
States.
Plate L IV ., fig. 1. a, living frond ; b, empty frond ; c d, end views.
mlb '