H ab. In pools.
Sussex, Wales; Italy, Austria, United States.
Flate X X V I I I . , Jig. 1. a h, living fronds; c, empty frond.
M ic za ste z ia s J en n e z i. Ralfs. Lesm. (1848),/?. 76, t. 11, f . 1.
Frond oblong, minutely granulated, segments five-lobed,
basal, middle, and end lobes cnneate, obscurely bipartite, and
their sub-divisions emarginate, or with merely a slight central
concavity, angles rounded, end lobe at external margin considerably
the broadest.
S i z e . Length 172 p ; diam. 120 p (R.) ; diam. 100-150 p
(W.).
Archer in Prit. Inf. (1861), p. 728. Cleve Sver. Desm. (1864),
p. 486. Lundell Desm. Suec. (1871), p. 11. Nordstedt Norges
Desm. (1873), p. 5. Wood F. Water Algte U.S. (1872), p.
146. Rabh. Alg. Eur. (1868), p. 194, in part. Jacobsen
Desm. Denm. (1874), p. 186. Wolle Desm. U.S. (1884), p.
115, t. 83, f. 1, 2.
H ab. In bog s.
Britain, Sweden, Norway, Denmark, United States.
Plate X X V I I I . , fig. 3. a, living frond; h, empty frond; c, end
view.
var. a. Ralfs. Desm., p. 76.
Granules like mere puncta, lobes slightly bipartite, sub-divisions
emarginate.
Sussex, Hants, Wales.
var. ft. Ralfs. Desm., p. 76.
Granules larger, giving a dentate appearance to the margin.
Sussex.
var. y. Archer in Pritch. Infus. (1861), p. 728.
Granules giving a rough appearance to the margin, lobes
slightly concave, margins rounded, not bipartite, without
emarginate sub-divisions.
M ic za ste z ia s angu lo sa . Hantseh. in Reinsch. Algenfiora (1867), p .
147, t. 8, / . 2.
Front view elliptic, more or less octangular, semi-cells five
lobed, terminal lobe deltoid, lateral lobes equally, two or three
lobate, angles of all the lobules unarmed, rounded. Sinus deep,
linear. Cell membrane densely but finely tuberculate.
S tzb. Length 255 p ; diam. 208 p (R.) ; length 305 p \
diam. 244 p.
Archer in Micr. Journ. xvi. (1876), p. 109. Lundell Desm.
Snec. (1871), p. 11. Nordstedt Norges Desm. (1873), p. 5.
Jacobsen Desm. Denm. (1874), p. 186.
Micrasterias Jenneri, var. h. angulosa, Rabh. Alg. Eur.
(1868), p. 194.
H ab. In pools.
Ireland, Warwickshire ; Sweden, Norway, Denmark.
Plate X X IX ., fig. a, living frond ; h, empty frond ; c, side view.
M ic za ste z ia s bzachypte za. Lund. Lesm. Sueo. (1871), 12, t. l , f . 4.
Large, about one-third longer than broad, circumference
elliptic, deeply constricted, semi-oells 5-lobed, end lobe extending
beyond the lateral lobes, narrowed gradually upwards, but
at the apex a little dilated into truncate two-spined angles,
terminal margin waved, concave, often with two spines, intermediary
and basal lobes equal, abbreviated, bilobulate, lobules
emarginate, furnished with incurved spines. Semi-cells with
the ventral margin spinulose. Membrane punctate.
S i z e . Length 191 /x j diam. 131 p (T.) ; length 200-214 /x;
diam. 140-150 p (L.) ; length 200-210 g ; diam. 140-150 p
(W-)- . .
Turner in Hoy. Micr. Journ. (1885), v., p. 937, t. xvi., f. 15,
Wolle Desm. U.S. (1884), p. 110, t. 32, f. 6, 7.
H ab. Mountain streams.
Bowness, Windermere ; Sweden, United States.
Plate X X X . , fig. 2. a, liviag fro n d ; b c, empty fronds; d, side
view ; e, end view.
G b n u s 15. EU A ST R UM . Lh r. (1831).
F ro n d lo nger th a n broad, com p re ss ed ; deeply co n stricted
in to two-lobed or sin n a te d segm en ts; segments u su a lly
p y ram id a l, 5 o r 3-lobed o r m ere ly sinuous, possessing v a riously
disposed c irc u la r in fla ted p ro tu b eran ce s (ra re ly
ab sen t) ; la te ra l lobes opposite, v e ry ra re ly ra d ia n t, ro unded
o r s in n a te d a t e x trem itie s ; end lobes a cu te ly incised or
em a rg in a te a t th e centre, ra re ly only c o n c av e ; c en tra l constric
tio n lin e a r.
Eu a stzum v e z zu co sum . Fhr. Abh. Berl. Akad. (1833), p . 247.
F ro n d somewhat lo nger th a n b road, ro u g h a ll oyer w ith
conic g r a n n ie s ; segments three-lobed, somewhat div erg en t,
a ll th e lobes broad, cnneate w ith a v e ry bro ad shallow exte
rn a l sinus. Em p ty fro n d inflated an d verruoose; semi-
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