66 IRIDACEAE. 



Family 22. IRIDACEAE. Iris Family. 



Perennial herbs; leaves narrow, equitant, 2-ranked; flowers 

 perfect, regular or irregular, mostly clustered, subtended by 

 bracts; perianth of 6 segments or 6-Iobed, its tube adnate to 

 the ovary, the segments or lobes in 2 series; stamens 3, inserted 

 on the perianth opposite its outer series of segments or lobes; 

 ovary inferior, mostly 3-celled; ovules mostly numerous in each 

 cell; style 3-cleft, its branches sometimes divided. 



Flowers very large; styles petal-like. 89. Iris, 66. 



Flowers moderate in size; styles filiform. 



Filaments united to the top; flowers usually blue. 90. Sisyrinchium, 66. 



Filaments united only at the base; flowers never 

 blue. 91. Olsynium, 67. 



89. IRIS. 



Herbs with creeping or horizontal, often woody and sometimes 

 tuber-bearing rootstocks; stems erect; leaves erect or ascending, 

 equitant; flowers large, regular, terminal, solitary or clustered; 

 perianth of 6 clawed segments united below into a tube, the three 

 outer dilated, spreading or reflexed, the three inner narrower, 

 smaller, usually erect or in some species about as large as the 

 outer; stamens inserted on the base of the outer perianth- 

 segments; ovary 3-celled; divisions of the style petal-like, 

 arching over the stamens, bearing the stigmas immediately under 

 their mostly 2-lobed tips; style-base adnate to the perianth-tube. 



Iris missouiiensis Nutt. Rootstocks stout, short, branched; stems 20-50 

 cm. tall, naked or with one or two leaves; leaves pale or glaucous, usually 

 shorter than the stem, 5-8 mm. wide; flowers violet-blue, rarely white, 2-4 

 in each umbel; bracts scarious, 2—6 cm. long, acute; sepals narrowly clawed, 

 5—6 cm. long, the honey guides yellowish; petals erect, shorter; capsule oblong- 

 obovate, somewhat 3-angled; seeds brown. Wet places, common. 



90. SISYRINCHIUM. Blue-eyed Grass. 



Perennial tufted slender herbs, with short rootstocks; stems 

 simple or branched, 2-edged or 2-winged; leaves linear, grass- 

 like; flowers rather small, mostly blue, terminal, umbellate, from 

 a pair of erect green bracts; perianth-tube short or none, the 6 

 spreading segments oblong or obovate, equal; filaments united 

 to the top; ovary 3-celled, each cavity several-ovuled ; style- 

 branches filiform, undivided, alternate with the anthers. 



Sisyrinchium idahoense Bicknell. Stems tufted, 20-45 cm. tall, compressed 

 and winged, the edges serrulate; leaves shorter than the stems, linear, acute, 

 1-3.5 mm. wide, all radical, or occasionally one on the stem; bracts long and 

 narrow; flowers 3-6, pedicelled, dark blue, with a small yellow center; perianth- 

 segments 12-18 mm. long, mucronate; filaments united to the top. Low 

 meadows, common. 



