218 Dr. Greville on some new species of Sargassum. 
vesiculis elliptico-sphericis petiolatis, petiolis foliaceis, dilatatis ; 
receptaculis compressis, valde dentatis, in racemo composito ag- 
gregatis. | 
Wight in herb. no. 17. 
Hab. in mari Peninsule Indiz Orientalis ; Wight. 
Root a callous disc, throwing up anumber of stems nearly two 
feet long, compressed, a line or more broad, undivided, giving off 
branches in a distichous manner, at intervals of from half an inch 
to an inch or more, 3-6 inches long, spreading, the whole forming 
a more or less oblong outline. Fruit-bearing ramu/i numerous, 
an inch long or more at the base of the branches, and dimi- 
nishing gradually to the extremity. Leaves: those produced 
from the main stem and especially on young plants often 2 to 
near 3 inches long, and from a quarter to half an inch in breadth, 
somewhat obtuse at the apex, either quite entire or obscurely 
repando-dentate, rarely furnished with a few sharp teeth towards 
the base. On the branches they are about an inch long, more 
or less lanceolate, more acute, often sharply toothed ; all furnished 
with a nerve and'pores. Vesicles somewhat elliptical, on young 
plants nearly as large as a small garden pea, supported on foli- 
aceous, dilated stalks 2-3 lines long. Sometimes the vesicle is 
winged and apiculate. Receptacles 1-13 line long, axillary, 
forming pedunculate, more or less divided racemes, the segments 
very irregular in shape, compressed, and toothed so as frequently 
to resemble a deer’s horn. : 
The most remarkable feature in this Alga is the oecasional 
length of the leaves which arise at the base of the primary 
branches, and which cause them to resemble the fronds of some 
of the Lycopodoid Polypodia. This is most conspicuous in a 
rather early stage of growth. The species however is liable, I 
suspect, to considerable variation ; and even on the same indivi- 
dual leaves may be seen almost, if not quite entire, while others 
are decidedly and sharply toothed. The latter oceur chiefly in 
the upper part of the plant, and towards the ends of the branches. 
The description and figure I have given must be regarded as pro- 
visional, for if my apprehensions be well-founded, a more exten- 
sive series of specimens will be required before a complete cha- 
racter can be drawn up. 
EXPLANATION OF PLATE IX. 
Sargassum obovatum. 
Termination of a branch. 
. Cauline leaf. 
Leaves accompanying the receptacles. 
. A raceme and leaf from the end of a branch. 
. Vesicles. 4 magnified. 
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