NORTH AMERICAN SPECIES OF JUNCUS. 241 
acute, mucronate or rostrate; it is shorter or longer than the sepals or equal to them; but all these 
characters vary within certain limits, in some species more than in others, and only the examination 
of a large number of specimens can decide about their constancy and value in a given species. The 
capsule is always three-valved (excepting again Jwncellus), opening into the cells, the valves 
bearing on their median line the placente either immediately (parietal placente and one- [430] 
celled capsule) or on a fold which extends to the centre and forms the dissepiments (central 
placentze and three-celled capsule); shorter dissepiments make semi-trilocular capsules. Very fragile 
dissepiments, which break off when the capsule opens, leaving the placenta central and detached 
(septifragal dehiscence), are found in J. repens (therefore generically distinguished by Desvaux), and 
to some extent also in J. Parryi, J. patens, and J. setaceus. The placente of J. Remerianus are 
enormously developed into a spongy mass, which fills the greater part of the capsular cavity. 
The capsule opens almost always from top to the middle or to the base; only in some of our 
species with subulate capsules (J. seirpoides, J. nodosus) the separation of ue valves commences in 
the middle, while at the top they remain united for some time. 
Seeds. —The seeds, when perfectly ripe, furnish some of the most interesting and constant char- 
acters, but they are so small and their markings so delicate that only a strong glass, or, better, a 
microscope with a magnifying power of fifty or sixty diameters, will properly exhibit them. It may 
not be useless to caution botanists not to be deceived by seeds loosely lying about with the speci- 
mens, as they very often will be found mixed. 
The seeds are ascending or (the elongated ones) more or less erect, with a lower end at the 
insertion of the funiculus and an upper one at the chalaza, both ends united by the rlhaphe and often 
by a distinct fold of the testa. The seeds are usually ohovate or oblanceolate, thicker at the upper 
than at the lower end, mostly terete, or, in rare cases (J. trifidus), angular, when a few large seeds 
are pressed upon one another. The ends are sometimes obtuse (/. bufonius), but commonly either 
abruptly or more gradually pointed, apiculate or even fusiform (J. padlescens, nodosus, scirpoides). 
Very frequently the testa is slightly elongated beyond both ends of the body of the seed and forms 
a small, membranaceous appendage (J. effusus, tenuis, marginatus); in such seeds the longitudinal 
fold of the testa, mentioned above, also becomes more distinct. In many and apparently more in 
American and in alpine or arctic species (J. Drummond, Greenii, Canadensis, etc.) these appendages 
become more conspicuous, and extend beyond the seed itself as empty, shrivelled, tail-like, white, 
or, rarely, reddish sacs. Such seeds have been called scobiform; their seed-coat is more loosely ad- 
hering and sometimes (J. stygius) can be readily removed. This elongation of the testa is of great 
diagnostic value, but the absolute or proportionate length of the appendages is extremely variable; 
even in the same capsule I find the lower seeds with shorter tails than the upper ones, 
and in J. Canadensis we see forms with such different length of tail that only the absence of [431] 
any other diagnostic characters can induce us to consider them as belonging to one and the 
same species. Much less can generic distinction be based upon this character, as was done by 
Desvaux, who comprised in his genus Marstppospermum all Junci with tailed seeds. Even E. 
Meyer's (in Synopsis Juncorum, 1822, and in Ledebour’s Flora Rossica, 1853) separation of the 
species with tailless seeds as a second section is unnatural, as not only tail-seeded kinds are found 
in all the great groups, but also species with intermediate seeds exist, which it would be difficult 
enough to eS properly. R. Brown (Prod. Nov. Holl., p. 258) settles the whole question in the 
following pithy sentence: Mee secernende sunt ee que seminibus gaudent scobiformibus, testa nempe, 
que in pluribus utrinque laxa, in hisce valde elongata. 
The size of the seed varies from 0.1 to 2.0 lines in length, it mostly ranges between 0.2 and 0.3 
lines, and rarely reaches 0.4 lines; the tailed seeds are usually larger than the others, averaging 
from 0.5 to 2.0 lines in length; even without the appendage, J. trifidus has the body of the seeds 
of 0.5, J. castaneus of 0.5-0.6, and J. stygius of 0.7-0.8 line in length. 
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