Jones: Flora of Illinois, 30. Juncaceae 89 



29. PoNTEDERlACEAE Dumort — Pickerelweed Family 



1. Flowers 2-lipped; stamens 6; leaves large, cordate to lanceolate; fruit a 1 -seeded 

 utricle I . Poniederia 



1. Flowers regular, salverform; stamens 3; leaves either reniform or linear; fruit a 

 many-seeded capsule 2. Heleranthera 



1. PoNTEDERiA L. — Pickerelweed 

 P. cordata L. Margins of ponds and streams. June-Sept. 



2. Heteranthera R. & P. 



1. Leaves reniform; flowers white or pale blue; stamens unequal; shallow water 



or muddy shores, s. 111. Aug.-Sept. Mud-plantain 



H. reniformis R. & P. 



1. Leaves linear, grass-like; flowers yellow; stamens equal; shallow water or 



muddy shores. July-Sept. [H. graminea (Michx.) Vahl; Zosterella dubia 



(Jacq.) Small] Water-stargrass H. dubia (Jacq.) MacM. 



30. Juncaceae Vent. — Rush Family 



1. Capsule many-seeded, 1- or 3-loculed, with axial or parietal placentae; plants glabrous 

 ; 1. J uncus 



1 . Capsule 3-seeded, 1-loculed, with basal placentae; plants often sparsely pilose 



2. Luzula 



\. Juncus L. — Rush 



L Inflorescence appearing lateral, the involucral bract erect, terete, simulating 

 a continuation of the stem; leaves reduced to sheaths. 

 2. Stamens 3; perianth 2.5-3.5 mm. long; anthers shorter than the filaments; 



stems densely tufted; ditches and marshy ground. Common Rush 



/. effusus L. 



2. Stamens 6; perianth 5-6 mm. long; anthers much longer than the fila- 



ments; stems usually arising singly from the rhizome and growing in 

 a row; shores and wet ground, n. 111. [/. balticus sensu auth., non 

 Willd.} /. litorum Rydb. 



L Inflorescence terminal. 



3. Leaves flat (or involute), not septate. 



4. Flowers borne singly on the branches of the inflorescence, not in heads. 



5. Annual; stem branched, the inflorescence more than half the height 



of the plant; sandy soil, roadsides, or ditches; June-Oct. Toad 



Rush /. btifonius L. 



5. Perennials; inflorescence less than half the length of the plant. 



6. Capsule longer than the perianth, reddish or dark brown; leaves 

 nearly terete. 

 7. Seeds cylindrical, 1 mm. or more in length, with caudate appen- 

 dages half as long as the body; damp shores, rare. July-Aug. 

 Cook Co., Bebb /. vaseyi Engelm. 



7. Seeds ellipsoid, 0.5 mm. long, short-pointed or obtuse; sandy 

 soil, rare, n.e. Ill /. greenei Oakes 5C Tuckerm. 



