.. Vill bear a fair proportion to a few acres of surfac 
NOTES OF ALGÆ. 199 
end of the pollen-tube with some part or other of the ovule, 
as observed in some, presents an instance of conjugation. 
It may not be irrelevant to state also that the development 
and structure of leaves in some of the compound Cellulares 
may assist in the investigation of the same in reference to 
those of vascular plants.* 
I must here acknowledge the assistance derived from 
Mr. Ralf? papers in the Transactions of the Edinburgh 
Botanical Society, and from Mr. Hassall’s book. The 
altitudes of the localities at which some of the following 
specles were collected in August last, had been ascer- 
tained on a former occasion: several of these measurements 
Were repeated ; and others made with the mountain Sympie- 
someter. A remark on the mode of collecting may not be 
irrelevant ; for other Botanists may be induced to send contri- 
butions Rom Alpine districts in other parts of the country. 
À few small phials ought to be provided, each of which is 
numbered : samples of muddy water, and of mud from moist 
places, and of matter adhering to submerged plants, &c., at - 
different altitudes, ought to be transferred to these phials, 
the localities being recorded. In this way, if kept cool, Des- 
midiee will remain fresh for weeks, and can be examined at - : : : 
leisure. It may be remarked that a small quantity of muddy n 
water, or of mud, in reference to the search for these | plant 
: = rence to flowering plants. The contents of the ph ls 
_be examined drop by drop under the €— the thick E. 
mud being diluted with water. p 
... Of some species here recorded, only a few ts not 
= Dar two or era were observed : Less however 
