GENUS i. RUSH FAMILY. 465 



Family 20. JUNCACEAE Vent. Tabl. 2: 150. 1799.* 

 RUSH FAMILY. 



Perennial or sometimes annual, grass-like, usually tufted herbs, commonly 

 growing in moist places. Inflorescence usually compound or decompound, pani- 

 culate, corymbose, or umbelloid, rarely reduced to a single flower, bearing its 

 flowers singly, or loosely clustered, or aggregated into spikes or heads. Flowers 

 small, regular, with or without bractlets (prophylla). Perianth 6-parted, the 

 parts glumaceous. Stamens 3 or 6, rarely 4 or 5, the anthers adnate, introrse, 

 2-celled, dehiscing by a slit. Pistil superior, tricarpous, I -celled or 3-celled, with 

 3-many ascending anatropous ovules, and 3 filiform stigmas. Fruit a loculicidal 

 capsule. Seeds 3-many, small, cylindric to subglobose, with loose or close seed- 

 coat, with or without caruncular or tail-like appendages. 



Eight genera and about 300 species, widely distributed. 



Leaf-sheaths open; capsule i- or 3-celled, many-seeded; placentae parietal or axial. i. Juncus. 

 Leaf-sheaths closed; capsule i-celled, 3-seeded, its placenta basal. 2. Juncoides. 



i. JUNCUS L. Sp. PI. 325 (1753). 



Usually perennial plants, principally of swamp habitat, with glabrous herbage, stems 

 leaf-bearing or scapose, leaf-sheaths with free margins, and leaf blades terete, gladiate, grass- 

 like, or channeled. Inflorescence paniculate or corymbose, often unilateral, sometimes con- 

 gested, bearing its flowers either singly and with 2 bractlets (prophylla), or in heads and with- 

 out bractlets, but each in the axil of a bract ; bractlets almost always entire ; stamens 6 to 3 ; 

 ovary i-celled or by the intrusion of the placentae 3-celled, the placentae correspondingly 

 parietal or axial; seeds several-many, usually distinctly reticulated or ribbed, often tailed. 



About 215 species, most abundant in the north temperate zone. Type species: Juncus acutus L. 

 The plants bloom in summer. [Latin, from jungo, to bind, in allusion to the use of these plants 

 for withes.] 



A. Lowest leaf of the inflorescence terete, not conspicuously channeled, erect, appearing 

 like a continuation of the stem, the inflorescence therefore appearing lateral; stem leaves none. 



1. Flowers bracteolate, inserted singly on the branches of the inflorescence. GENUI.M. 



Perianth-parts green, or in age straw-colored. 



Perianth-parts equalling or exceeding the capsule, all acute. 



Stamens 3 ; leaf of the inflorescence much shorter than the stem. 



Capsule without a distinct apical papilla. i. J. efftisits. 



Capsule with a distinct apical papilla. 2. J. conglomerate. 



Stamens 6 ; leaf of inflorescence about equalling the stem, or longer. 3. /. filiformis. 

 Perianth-parts reaching only the middle of the capsule, inner obtuse. 4. /. gymnocarpus. 

 Perianth-parts with a chestnut-brown stripe down either side of the midrib. 5. /. balticus. 



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



Perianth-parts pale brown ; seed tailless. 6. /. Roemerianus. 



Perianth-parts green, or in age straw-colored; seed tailed. 7. J.maritiinus. 



B. Lowest leaf of the inflorescence not appearing like a continuation of the stem, or if so, 

 conspicuously channeled along the upper side, the inflorescence usually appearing terminal. 



1. LEAF-BLADE TRANSVERSELY FLATTENED (INSERTED WITH ITS FLAT SURFACE FACING THE 

 STEM), OR TERETE AND CHANNELED, NOT PROVIDED WITH SEPTA. 



* Flowers bracteolate, inserted singly on the branches of the inflorescence, sometimes clustered or 



congested, but never in true heads. POIOPHVLLI. 

 Annual ; inflorescence, exclusive of its leaves, more than one-third the height of the plant. 



8. /. bufoniu:. 



Perennial ; inflorescence, excluding leaves, not one-third the height of the plant. 

 Leaf-blade flat, but sometimes involute in drying. 



Inflorescence i-3-flowered ; leaves with fimbriate auricles. 9. /. Irifidits. 



Inflorescence, except in depauperate specimens, several-many-flowered ; leaves with 



entire auricles. 



Cauline leaves i or 2, rarely wanting; perianth-parts obtuse. 10. /. Gerard i. 

 Cauline leaves none ; perianth-parts acute or acuminate. 



Auricles at top of leaf-sheath cartilaginous, yellow when dry. 1 1. /. Dudley i. 

 Auricles at top of leaf-sheath membranous, whitish or brownish. 



Inflorescence exceeded by its lowest leaf ; flowers not conspicuously secund. 

 Auricles of the upper leaves usually y^'-i 1 /*" long, thin, membranous; peri- 

 anth parts widely spreading. 12. /. tennis. 

 Auricles less than J/" long, thin only at the margin ; perianth parts appressed 



to the capsule. 13. /. interior, 

 Inflorescence not exceeded by its lowest leaf ; flowers conspicuously secund. 

 14. /. secundus. 



* Text contributed by Mr. FREDERICK V. COVILLE. 



