ENGELMANN—NORTH AM. SPECIES OF JUNCUS. 437 
axis, which often almost seem to constitute an umbel, but 
which are mostly of very different length, the lowest ones 
being by far the longest. These rays or branches often re- 
peat the development of the main axis several times, or are 
regularly dichotomously divided, or they assume the appear- 
ance of one-sided spikes with lateral inflorescence, somewhat 
atter the fashion of the Borraginew. A remarkable example 
of this is furnished by J. tenwis, var. secundus, which form 
also proves that this uni-lateral development of the inflores- 
cence can by no means constitute specific distinction, as a 
series of intermediate forms are not wanting. We observe a 
similar condition in J. Balticus and the var. Pacificus,; the 
eastern form has the ordinary panicle, while that of the 
Pacific coast bears on the branches uni-lateral flowers. 
In many others, and especially in all those that have knotted 
leaves, the flowers are arranged in heads. These heads con- 
sist of few, or are (often in /. pelocarpus) reduced to single, 
flowers, or they bear a great many, and the different forms of 
the same species often vary immensely in this respect. Thus 
we find from 2 or 3 to 50 flowers in each head of the different 
forms of J. pallescens, 6 or 9 to 100 in the forms of J. nodosus, 
and 2 or 3 to 80 or 90 in J. Canadensis. These heads are 
single, or composed of several heads crowded together, when 
they appear lobed. I have seen the axis of the heads abnor- 
mally elongated, thus changing them into spikes 9-12 lines 
in length in three different species, all found in the southern 
States. In all of them the lower flowers seem to remain 
sterile, and only the uppermost ones bear fruit; or, after the 
earliest flowers have performed their functions, the axis, per- 
haps in a wet season, continues to grow and produces a sec- 
ond crop of flowers. J. cylindricus, Curtis, is such a spicate 
form of J. marginatus; I have also seen it in J. pallescens, 
var. fraternus, and most beautifully developed in J. Canaden- 
sis, var. longicaudatus. In this last specimen numerous rays 
form a rather compact almost level-topped umbel, and each 
ray bears a head ot 3 to 5 or 6 sessile, diverging spikes. The 
heads-are either single, terminating the stem like the head 
of an Allium, or they form a more or less compound inflores- 
cence similar to that of the single flowers. 
F'lowers.—The flowers of these plants consist normally of 5 
circles, each of 3 component parts; 3 outer and 3 inner peri- 
gonial leaves, which we call, on account of their herbaceous 
texture, sepals ; 3 outer and 3 inner stamens and 3 carpellary 
leaves; each of the circles alternating with the next one, so 
that the 6 stamens stand before the 6 sepals, and the 8 
carpels before the 3 outer sepals; but the 3 stigmas, as well 
as the-valves of the capsule, before the 3 inner sepals. The 
third circle, consisting of the 3 inner stamens, is some- 
times wanting. Only in one instance, in the only species of 
[May, 1866.] 28 
