* 
NEW POTAMOGETONS 149 
wap an unstable condition, and it is probably to be considered 
a or state rather than a fixed variety. None the less, it is 
a sey Stinarkable plan 
EXPLANATION OF PLATE on 
Fissidens exsul, sp. nov.—Fig. 1. Plant, 2. Leaf, x 50. 3,4, 5. 
Leaf-apex, x 120. 6. Gatepers, x 50. 7. Gaile with ei 1 ee 
8. Upper cells, x 400. 9. Cells of sheathing —— x 400. . Peristome 
Fissidens rufulus B. & S., forma. Figs Pa Leaves, x 25. 5. Part of 
sheathing lamina, showing intramarginal scaee, x 150. 
NEW POTAMOGETONS. 
By ARTHUR BENNETT. 
Potamogeton australiensis, sp. nov.—For some time scraps 
of a Potamogeton from Australia have been passed in review, but 
with no definite result. Lately Mr. Maiden, the Director of the 
Sydney Botanic Gardens, has sent me numerous unnamed Aus- 
tralian specimens. note them a good sheet of what has passed 
for P. coloratus Hornem r. jamaicensis Griseb., containing 
to e to the Australian plant. When this can be. 
studied im ie it may be that some alterations in the descriptions 
will be needed. 
P. australiensis mihi.—Caulis 1 m. longus, simplex. Folia 
submersa heer uae: oe nervis 7, inferiora lineari- 
sag lata, 1 dm. longa, 5 mm. lata; intermedia 6°15 cm. longa, 
m. lata, nervis 11; aes oblongo-lanceolata vel ovata, 
tranaltielstie petiolata in petiolo subcordato 15 abies Folia 
emersa coriacea, nervis interdum reticulato-ven Sti: 
gemi-acute, 2 em. long, striate. Pedunculi rae zequales, 
produces floating leaves. In one specimen the passing of the 
Si tiargod into the emersed is well seen, two-thirds of the leaf 
d the structure of the emersed, one-third that of the 
thirds, wanting with one-third. In this plant (as in coloratus) we 
have a great diversity of leaf-form, so much so that, seen a 
two, if not three, species might (with some excuse) be 
