ON SAGINA NIVALIS. 341 
to near the level of the sea, and such is probably the case in Spitz- 
bergen and Samojed-land. Our station on Ben Lawers must be very 
elevated, for it there, as Dr. Balfour believes, accompanies Ælsine ru- 
bella. 
Fries remarks that S. saxatilis has a barren central stem [rosette], 
which throws out from its base lateral, procumbent, rooting shoots, 
each ending in a long peduncle; but that the stems of S. nivalis form 
a cæspitose mass, are erect and. short, and bear short peduncles. He 
adds that the petals of S. saxatilis are slightly emarginate, but that 
those of S. nivalis are entire. These remarks agree admirably with my 
specimens received from Dr. Balfour, but by some oversight Mr. 
Sowerby has figured what he calls S. nivalis: (Syme’s E. B. t. 250 bis) 
witha very decided rosette, and Mr. Syme says of the primary or cen- 
tral stem that it is * reduced to a barren rosette of leaves, never bear- 
ing any flowers." It is clear that if the specimen: has this structure, 
it cannot be the S. nivalis as described by Fries, I have. before me 
specimens of the true plant, gathered by the late Professor Blytt in 
Norway and issued by Fries, which agree well with those gathered on 
Ben Lawers, except that on one of them there is an appearance of a 
rosette; but careful examination convinces me that there really is none, 
and the other specimen is conclusive against its existence. My ex- 
amples from Ben Lawers certainly have no rosette. It should be re- 
collected that much care is requisite, for one of the forms of S. apetala 
seems to have a rosette until after many of the branches have flowered ; 
but in S. apetala this false rosette invariably grows into a flowering-stem 
as the age of the plant advances, and ultimately this central stem does not 
in any respect differ from the lateral stems. It is possible that 5. nivalis 
may pass through similar stages in its growth. How different this 
structure is from that of the true rosette-bearing plants is seen by an exa- 
mination. of S. procumbens, in which the rosette never increases in length 
after it is once formed, but is always manifest at the top of the root- 
stock. As soon-as the rosette is well developed it ceases to grow until 
the spring of. the following year, then its terminal bud advances slightly 
so as to produce a new central rosette of leaves with axillary buds to 
replace that of the preceding year, the leaves of which latter, together 
with its branches, have faded and lost all their vitality. As Mr. Syme 
justly remarks, S. nivalis very closely resembles some states of S. ma- 
ritima ; but the former plant is perennial, has tapering acute leaves, 
VOL. 11, [NOVEMBER 1, 1864.] 2A 
