7- 1923 
ENGELMANN—N. AM. SP. OF GENUS JUNCUS. 425 
will stand in place of expensive plates, and will, it is believed, 
be far preferable to them. 
Arrangement.—The numerous species of the Genus Juncus* 
have been divided into sections according to characters taken 
from their organs of vegetation, their stems and leaves and 
also their inflorescence, more than from the differences found 
in their flowers or fruits. In these most essential parts all 
the species show a remarkable uniformity, which will only 
permit us to make use of them to characterize minor divisions, 
and for specific diagnosis. Desvaux (Journ. Bot., Vol. L, 
Paris, 1808) had already separated our Juncus repens, on 
account of a peculiarity in the dehiscence of the capsule, and 
some alpine species, because of their long-tailed seeds, as 
two distinct genera, Cephaloxys and Marsippospermum. 
But we know now that other species of far different alliance 
form a transition from the ordinary loculicidal to the sep- 
tifragal dehiscence, and that species of all forms and sections, 
and otherwise very dissimilar among themselves, have tailed 
seeds, and that others exhibit all the transitions from 
the tailed and loosely tunicated to the merely pointed and 
closely coated seed. From the following it will appear that 
these genera cannot stand even as sections. 
Vegetative Organs.—The different forms of the rootstalks, 
and of the stems and leaves of these plants, are so well 
known that I need not here dwell upon them; by their dif- 
ferences the principal types of Junci are best characterized ; 
those that produce no leaves or leaves equal to the stem itself, 
those that have channelled or flattened leaves, and those that 
bear knotted leaves. But I must say that we have forms that 
seem to bridge over these apparently well marked distinctions, 
and which again prove that nature knows nothing of our 
systematic subtleties, and that our systems are only an imper- 
fect aid for our limited comprehension. ‘To give an example 
—no section of Juncus seemed to be better characterized and 
more natural than that of the true Jwnci with naked stems 
and so-called lateral inflorescence. To this section we are 
bound to refer J, Drummondi and J. Hallii, while-/. biglu- 
mis, which can scarcely be separated from them, is, in all our 
systematic works, far removed from them. Again, J. Vaseyi 
comes so close to J. Hallii that we would hesitate whether 
to class it with this or with the similar looking but flat-leaved 
J. tenuis, if J. Greenii did not unite it more directly with 
the latter one. 
The form of leaves is not quite constant. While those of the 
articulate Junci are usually described as terete or compress- 
ed-terete, the observations of our southern botanists prove 
* Steudel, in his Plante Glumacez, 1855, enumerates 196 species, many 
of them, however, undoubtedly nominal ones, 
