Flora of the Paloasc Region 47 



Flowers white, peduncled. T. oyatum. 



Flowers purple, sessile. T. petiolaTum. 



T. OVatum Pursh. Stems 15-40 cm. tall, from a stout horizontal root- 

 stock, 2-5 cm. long: leaves broadly ovate, acuminate or acute, 5-15 cm. long, 

 nearly sessile: flowers odorous; peduncles erect, 3-6 cm. long: petals lanceolate, 

 acute, white, in age changing through various shades of pink to dark red, 

 exceeding the green sepals: anthers yellow. Thatuna Hills, in woods. 



T. petiolatum Pursh. Stems short, usually subterranean, enclosed in 

 sheath-like bracts and arising from a stout oblong upright rootstock: leaves 

 oval or orbicular, 5-15 cm. long, petioled: flowers sessile: petals narrow, dark 

 purple, scarcely longer than the sepals: anthers dark purple. Rich hillsides 

 and copses. 



Family 16. IRIDACEAE. 



Perennial herbs: leaves narrow, equitant, 2-ranked: flowers per- 

 fect, regular or irregular, mostly clustered, subtended by bracts: 

 perianth of 6 segments or 6-lobed, 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 in- 

 ferior, mostly 3-celled; ovules mostly numerous in each cell; style 

 3-cleft, its branches sometimes divided. 



Style-branches opposite the anthers, very broad, petal-like. 



74. IRIS. 

 Style-branches alternate with the anthers, slender or filiform. 



75. SISYRINCHIUM. 



74. 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. 



I. missouriensis 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- 

 pbovate, somewhat 3-angled; seeds brown. Wet plages, common. 



