254 



JUNCACEAE 



Family 2. JUNCACEAE Vent. Rush Family. 



Perennial or sometimes annual often tufted herbs, usually grass-like in habit. 

 Inflorescence paniculate, corymbose or umbel-like, compound, or rarely reduced to a 

 single flower. Flowers sometimes collected into dense heads. Perianth regular, incon- 

 spicuous: parts (sepals and petals) 6, chaffy, often quite similar. Androecium of 3 

 or 6, or rarelj^ 4 or 5, stamens. Anthers adnate, 2-celled: sacs introrse, opening by slits. 

 Gynoecium of 3 united carpels. Ovary 1-3-celled. Stigmas 3. Ovules 3-many, 

 anatropous. Fruit a locuhcidal capsule, but sometimes breaking up irregularly. 

 Seeds .3-many, sometimes with caruncular or tail-like appendages. 



Leaf-sheaths open: capsules 1- or 3-celled with axile or parietal placentae: seeds many. 1. .Juncus. 



Leaf-sheaths closed: capsules 1-celled with basal placentae: seeds 3. 2. Juncoides. 



like a continuation 



1. J. effusus. 



2. J. gymnocarpus. 



3. J. Roemerianus . 



1. JUNCUS L.i 



Caulescent or scapose often swamp-inhabiting herbs, with glabrous foliage. Leaves 



terete or flattened: sheaths with free maigins. Flowers in often apparently lateral panicles 



or corymbs or heads, either singly and with 2 bractlets (prophylla) or when in heads each 



merely in the axil of a bract. Bracts usually entire. Stamens 6 or 3. Ovary 1-celled or 



by the intrusion of the placentae 3-celled. Seeds often tailed, usually distinctly reticulated 



or ribbed. Rush. 



Lowest bract of the inflorescence terete, not markedly channeled, erect, appearing 

 of the scape, the inflorescence thus appearing lateral. 

 Flowers bracteolate, inserted singly on the branches of the infioresoence. 



Stamens 3: sepals and petals about as long as the capsule: petals acute or 



acuminate: capsules of an obovoid type. 

 Stamens 6: sepals and petals about }/2 as long as the capsule: petals obtuse: 

 capsules of an ovoid type. 

 Flowers not bracteolate, inserted in heads on the branches of the inflorescence. 

 Lowest bract of the inflorescence not appearing like a continuation of the scape 

 (or if so, markedly channeled along the inner side), the inflorescence there- 

 fore usually appearing terminal. 

 A. Leaf-blades with their flat surfaces facing the stem, or terete and channeled, 

 not provided with node-like septa. 

 a. Flowers bibracteolate, inserted singly on the branches of the inflorescence, 

 sometimes clustered, but never in true heads. 

 *Leaf-b!ade8 flat, but sometimes involute in drying so as to appear terete. 

 (See also J . dichotomus below.) 

 Annual: inflorescence, exclusive of its bracts, more than }4 the height 



of the plant: anthers shorter than the filaments. 

 Perennial: inflorescence, exclusive of its bracts, less than }4 the height 

 of the plant (except sometimes in J. Georgianus, and the anthers 

 then longer than the filaments). 

 Inflorescence 1-3-flowered: leaves with fimbriate auricles. 

 Inflorescence several-many-flowered: leaves with entire auricles. 

 Plants caulescent: sepals and petals obtuse. 

 Plants scapose: sepals and petals acute or acuminate. 



Auricles at the summit of the leaf-sheath membranous or 

 scarious, whitish. 

 Auricles membranous, scarcely scarious, rarely if at all 

 prolonged beyond the point of insertion. 

 Sepals and petals 2.. 5-4 mm. long: capsule about as 

 long as the perianth. 

 Flowers and fruit conspicuously secund: perianth 

 2.5-3.5 mm. long: anthers longer than the 

 filaments: bract shorter than the inflores- 

 cence: capsules oval. 

 Flowers scarcely or not at all secund: perianth 

 3^ mm. long: anthers shorter than the fila- 

 ments: bracts exceeding the inflorescence: 

 capsules ovoid-oblong or oblong. 

 Sepals and petals 4-6 mm. long: capsules shorter 

 than the perianth. 

 Plants 4-7 dm. tall: anthers and style very short. 

 Plants 1-4 dm. tall: anthers linear, longer than 

 the filaments: style often 1-1.5 mm. long. 

 Auricles scarious, markedly prolonged beyond the point 

 of insertion. 

 Capsules oblong, about equalling the perianth, 3- 



celled: sepals and petals erect or appressed. 

 Capsules ovoid or oval, % as long as the perianth or 

 less, 1-celled: sepals and petals more or less 

 spreading. 

 Auricles at the summit of the leaf-sheath cartilaginous, 

 yellow to yellow brown. 



4. J. bufonius. 



5. J. trifidus. 



6. J. Gernrdi. 



7. J. sccundus. 



8. J. interior. 



9. J. Arizonicus. 



10. J. Georgianus. 



11. J. brachyphyllufs. 



12. J. tenuis. 



13. J. Dudleyi. 



1 Prepared with the assistance of Mr. Frederick V. Coville. 



