ENGELMANN — NORTH AM. SPECIES OF JUNCUS. 429 



The proportion of stamens and sepals, and of anthers and 

 filaments, is often very constant, but in some species they 

 vary very much, as may be seen in J. scirpoides, the different 

 forms of which bear stamens of different length and anthers 

 of different size without exhibiting other characters of suffi- 

 cient specific value. 



In a rare form of J. Reamer ianus I find both circles of 

 stamens suppressed or rather undeveloped and in a rudiment- 

 ary state, so that those plants become uni-sexual. Correspond- 

 ing male plants may perhaps yet be discovered. 



Filaments are always present ; in some species they are 

 very short, in others elongated, in all dilated at base, and, at 

 least in the hexandrous ones, more or less united. Their 

 base, Avhich in the young flower adheres to the base of the 

 pistil, after fecundation remains attached to the base of the 

 sepals. 



The shape of the anthers is of slight importance; they are 

 longer or shorter, linear or oblong, in some species pointed 

 or cuspidate, in most others obtuse or emarginate, more or 

 less sagittate at base, but these characters show little con- 

 stancy. 



Pistil. — The pistil exhibits great differences in its form and 

 furnishes good and generally constant characters. The ovary 

 is obtuse or acute, gradually or abruptly elongated into the 

 style ; this organ is often very short but in many species it 

 has the length of the ovary, or even exceeds it; in a few spe- 

 cies only it is variable, e. g. in J. scirpoides, which in this as 

 in most other organs offers a degree of variability scarcely seen 

 in any other species. The stigmas are longer or shorter than 

 the ovary with the style, always (except in tTuiicetlus) three 

 in number, very slender and more or less twisted; mJ. acutus 

 they are short and thick, and in J. stygius, as already Lin- 

 naeus remarks, short and recurved. In just expanding flowers 

 the length of the stamens is often equal to that of the ovary 

 and style together, so that the stigmas only emerge from 

 between the anthers, or they are equal to the ovary alone 

 when the whole style with the stigmas protrudes over the 

 anthers. 



Capsule. — The capsule is diagnostically one of the most 

 important organs in Junci. It varies from globose to ovate, 

 obovate, prismatic, pyramidal or subulate, terete or angular, 

 retuse, obtuse or 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 juncellus), opening into the cells, the valves bearing 

 on their median line the placentae either immediately (parie- 



