Mr. Douglas in great abundance in North America, from 
Lake Winipeg to the Western Ocean, between 38° and 49° 
of northern latitude. It has now almost become naturalised 
in the Garden of the Horticultural Society, where our 
drawing was made. If sown at different seasons, it will 
continue to flower during the whole year, excepting the 
severest months of winter. 
The genus Collomia, like several other genera of Po- 
lemoniacex, is remarkable for a mucous matter in which 
the seeds are enveloped: if the seeds are thrown into 
water, this mucus instantly dilates and forms around them 
like a cloud, and in a short time acquires a volume 
greater than that of the seed itself.. Upon examining the 
cause of this singular phenomenon, it will be found to depend 
upon the presence of an infinite multitude of eaceedingly delicate 
and minute spiral vessels, lying coiled up, spire within spire, on 
the outside of the testa; when dry, these vessels are confined 
upon the surface of the seed by its mucus, without being 
able to manifest themselves; but the instant water is ap- 
plied, the mucus dissolves, and ceases to counteract the 
elasticity of the spiral vessels, which then dart forward at 
right angles with the testa, each carrying with it a sheath 
of mucus, in which it for a long time remains enveloped, as 
if in a membranous case. This observation is particularly 
interesting, inasmuch as spiral vessels are, we believe, 
now for the first time seen upon the external surface of) 
a vegetable organ; they have been hitherto supposed. to 
exist solely within the substance of plants, accompanying 
either the medullary sheath, or the veins which diverge 
from it,—with one or two exceptions, of which the seed of 
Casuarina is one. 
Apabs 
Nore. 
There is another yery fine species of this genus in the Gardens, likewise 
discovered by Mr. Douglas in North-west America, and called by him Col- 
lomia grandiflora. It differs from the present in its much larger flowers and 
lucid leaves, and may be specifically characterised thus :— 
_ C. grandiflora ; foliis oblongo-lanceolatis integerrimis lucidis ciliato- 
glandulosis, caule ramoso pubescente, capitulis hemisphericis pruinosis, 
corolla ventricosd: limbo erecto. 
