— 46 — 
It is a species not easily confused, and one whose immediate relationships 
are not at once clear, though for some time it has been generally recognized 
that it belongs to the group Cuspidata, and it probably finds its nearest affinity 
in the several species last considered. Its branch-leaves are hardly undulate 
when dry, though a slight tendency in that direction is sometimes observable, 
and are considerably shorter and wider in proportion to their length, giving 
them an ovate rather than lanceolate shape; in section their chlorophyll cells 
are particularly broad in their exposure on the dorsal surface and even convexly 
bulging, but barely, if at all, reaching the ventral surface, where the empty cells 
are strongly bulging. The cortical cells of the stem are clearly differentiated 
as in all the following species of the group, normally in two layers of not very 
large cells with fairly thin walls. Stem-leaves, branch-leaves, perichaetial leaves 
belong otherwise to the general type of the Cuspidata. The species is often 
used for illustration of the retort-cells of the Sphagnum-branch, as these are 
remarkably well developed in it, standing out in marked contrast to the other 
small cells of the branch. The color is usually a delicate yellowish green, rarely 
more deeply pigmented yellow-brown. It is generally regarded as dioicous, 
though Warnstorf describes it as polyoicous. I have not succeeded in demon- 
strating monoicous plants, though in the coastal region of northern Europe I 
have found the species fruiting rather frequently. 
Its distribution is remarkable and with us confined to immediate proximity 
of the coast. It may thus be found in various localities, often widely separated, 
from Labrador to New Jersey, and on the Pacific coast from Alaska to Vancouver 
Island. The circumstances of its occurrence, manner of growth, etc., in a favor- 
able part of its American range are given in considerable detail by Nichols. 6 
In Europe it extends northwest to the Faroes and southwest to Portugal, but is 
not confined to the coast, being reported from most of the mountain systems 
southward to the Alps. In Asia it is known only from Japan. The facts would 
seem to indicate Europe as the center of distribution of this species, and it is 
in general doubtless true that if any region can lay valid claim to being the orig- 
inal home of Sphagnum , it is northern Europe. 
20. Sphagnum cuspidatum Ehrhardt, 1795. 7 About the application of this 
name there seems neither to have been nor to be any question. A question which 
has often been raised is whether or not it is specifically distinct from S. recurvum. 
With the segregations of recent decades this question has ceased to be urged, 
and in my own experience I have failed to find anything that convinces me that 
S. cuspidatum is a mere aquatic form of S. recurvum, though there can be no 
doubt whatever that the relationship is a close one For practical distinction 
a number of characters have been and may be used, but in doubtful cases one 
or more of them may be found to fail. It has been noted for example that pen- 
dent branches of S. recurvum are generally long and closely appressed to the stem. 
6 The Vegetation of Northern Cape Breton Island, Nova Scotia, 422 and elsewhere. 1918. 
7 On the date of Hoffmann’s separate publication of the Sphagna for the second volume of 
his Deutschlands Flora cf. my note in Bryologist, XX, 84. 1917. 
