19'i FBESH-WATER ALGIE FROM BDKMA.
L o n g . 242^4; l a t . 2 0 ^ ; lat. a p i c . om. (Pi. x i i i , fig. 20). T h e n u m b e r of a t r i o l a t i o ns
v i s i b l e a c r o s s t b c cell w a s 17.
Hal.—Springs on the r i r e r b a n k at B h a m o (No. 2 1 5 0 1 ).
V a r . BREVE v a r . n.
V a r . m u l t e b r e v i o r , m i n u s a t t e n u a t a polos v e r s u s.
L o n g . 1 4 0 - 1 6 1 m ; lat. 22-25ya; l a t . apic. 7-%-Oi^.
/ / n i . — B e t w e e n T h i n g a n - n y i - u a u n g and K a w k a r e i k , in the side c h a n n e l of a
s t r e a m (No. 2 4 4 8 3 ).
5 1 . CLOSTERIUM KUTZIHGII Brt^b. L i s t c D e s m . 1866, p. 156, t. 2, f. 4 0 ; W. &
G . S. W e s t , B r i t . D e s m . i, 1904, p. 186, t. 25, f. 6 - 1 1.
Bob.—Between T h i n g a n - n y i - n a u n g a n d K a w k a r e i k , in t h e s i d e - c h a n n a l of a s t r e am
( N o . 2 4 4 8 3 ).
5 2 . CLOSTERIDM ROSTBATDM E l i r e n t ) . , 1832 ; R a l f s , Brit. Desm. 1848, p. 175,
t . 30, f. 3.
M o m a u k , east of B h a m o (No, 2 1 5 5 1 ).
5 3 . CLOSTERIUM SETACEUM E h r e n b . , 1834; W. & G. S. W e s t , B r i t . D e s m . i,
1 9 0 4 , p. 190, t. 20, f. 9 - 1 3,
K y a u k t a g a in the P e g u d i s t r i c t (No. 2 2 1 2 4 ) . M a n s a n g near H s i p aw
(NO. 24193).
G e n u s : Pleurotcenium Niig.
5 4 . PLEUROTJINIUM OVATUM N o r d s t . A l g . B r a s i l . 1877, p. 18.
Docidium ovatum N o r d s t . D e s m . B r a s i l . 1870, p. 205, t. 3, f. 37.
V a r . TDJIIDDM M a s k . F u r t h e r N o t e s N. Zeal. D e s m . 1889, p. 29, t. 6, f. 54,
L o n g . 2 4 6 - 2 6 5 / i ; l a t . m a x . 96-102^^; l a t . apic. 3 1 - 3 3 / t ; l a t . i s t h m . 3 7 - 3 8 - 5 ^ ( P I.
XIII, figs. 8, 9).
M a n s a n g n e a r H s i p a w (No. 2 4 1 9 3 ).
This Desmid oecuired ia abundance, and it only difiers from Haskell's New Zealand variety in
h a v i n g a rather narrower isthmus. The flattened granules at the apices of the semicelk were ntae
or ten in number.
When the cell becomes disarticulated into two semicelh, the oblique junction oE the new and
old half-cells sometimes becomes very evident. This area of junction gradually thins off like a wedge
and forms for a short distance part of the wall of the other semicell. Thus, a single semioell
showing this overlapping area appears at first sight to be furnished with a downwardly-curved hook
on each aide of the isthmus {-vide PI. siii, fig. 9). This structure was misinterpreted by Turner in
Docidiwn roUmdaium Turn. (Freshw. Alg. E. India, 1893, p. 37, t. 7, f. 2a), and the hook-liko
appearance figured in a somewhat exaggerated manner. Turner's species seems to be merely a f o rm
of this variety.
5 5 . PLEUEOT^NIUM TEOCHISCUM W . & G. S. W e s t , S o m e N. A m e r . Desm. 1896,
p . 235, t. 13, f. 4, 5 ; F r e s h w . A l g . C e y l o n , 1902, p. 142, t, 19, f. 7, 8.
L o n g . 3 4 2 / i ; lat. ad bas. s e m i c e l l . 31*5/^; l a t . ad m e d . s e m i e e l l . 2 8 ^ ; l a t . a p i c,
U a l . — l a t h e K a n g y i at M u d o n (No, 2 4 5 0 5 ).
t h e largest speeimenB
,ses had one slight basal
a very slight inflation
PLEUROTiENlUM.
The specimens agreed exactly with those observed f r om Ceylon and from aeveral parts of the
U n i t e d States. Whether PL irochiscum is identical with Fl. teticlatum (Josh.) Lagerh. or not
appears to be a question which can only be decided by an examination of the original specimen
of Joshua's 'Docidium teiselalum.' Judging irom the experience we have already obtained of the
inaccuracy of many of Joshua's figures and descriptions, the identity is quite probable. Both species
are also very possibly synonymous with Bailey's 'Docidium r.rr»co««w,' but agam the published
accounts of this species are not sufficiently reliable to admit of a critical comparison.
5 6 . PLEUROT.ENIUM CEISTATUM ( T u m . ) Borge, T r o p . U. s u b t r o p . Sussw. Chlor.
1 8 9 9 , p. 15.
Doeidium eridaUm Turn. F r e s l i w . Alg, E. I n d i a , 1893, p. 32, t. 4, f. 7.
F o r m a m a r g i n i b u s s e m i c o l l u l a r u m non u n d u l a t i s ; t u b e r c u U s 3 4 - 3 6 ad a p i c om
( 1 8 - 1 9 visia).
L o n g . 6 8 0 - 1 1 3 0 ^ . ; k t . bas. semicell. 36-66/^; lat. ad med. s e m i c e l l . 2 9 - 5 6 ; -;
l a t . ad apic. 33-5-59/^. (PI. x i i i , fig. 11).
M a n s a n g n e a r H s i p a w (No. 2 4 1 9 3 ).
This Fkm-otamuim occurred abundantly and was very variable in
being double the size of the original I n d i a n plants. The samicells in a
inflation, parallel or subparallel sides without any tra.-e of undulations,
under the apex, which was slightly contracted immediately below the crown of tubercles. Iho
Dumber of tubercles on the apex was 34, or sometimes 36, whereas Turner gives 30 as the number
on his Indian specimens. Turner aho states " m a r g i n e leviter undulatum," but his figure indicates
ahnost parallel sides. The figure given by Borge (l.o. t. 1, f. 11) of a form from Cuba bas not
more than 18 or 20 tubercles at the apex of the semicell and in this character ifc diliers considerably
from Loth the Indian and Burmese forms.
Two other species described by Turner must be considered as forms of Fl. crktoium. Theso
are ' DocidHm orieniale Turn.' and ' Docidia?^ a/lindricum Turn.' The former is destitute o£ the
slight inflation below the crown of taberclos, and the number of tubercles is 36-44, The latter is
a shorter form with 38-40 apical tubercles.
The plants in question might be considered as follows:—
Pleurotanmm criitaium (Turn.) Borge. PI. magnum, cellulis diametro 17-19-plo longloribus,
f e r e rectum vel leviter cm-vatum; semicellulas cylindricfe, ad basin leviter inflatie, lateribus
parallelis (vel levissime undulatis?), apice leviter inflate, tuberoulis parvis 30-36 (visis
16-19) ornato.
Forma ovienialis (Turn.) nob. Apice semioellularum nou inflate sed paullo expanse, tuberculis
3 6 - 4 4 ^visis 18-22) ornato.
Forma cylindrica (Turn.) uob. Cellulis diametro 10-plo longioribus, ad apices oum tuberoulis
3 8 - 4 0 (visis 20).
5 7 . PLEUROT^NHIM CUYABENSE Borge, Alg. erst. R e g n e l l . E x p e d . ii. D e s m id
1 9 0 3 , p. 84, t. 2, f. 8.
F o r m a IKORNATA. ( P I . x i i i , fig. 10).
F o r m a p a u l l o m a j o r , a p i c i b u s s e r a i c e l l u l a i ' um sine t u b e r c u l i s.
L o n g . 600M; lat. a d bas. s e m i c e l l . 54M; l a t . a d a p i c . 31-5M.
Z T a J . — K y a n k t a g a , P e g u d i s t r i c t ( N o . 22124).