53 6 IRIDACEAE. Vol. I. 



Family 29. IRIDACEAE Lindl. Nat. Syst. Ed. 2: 382. 1836. 



Iris Family. 

 Perennial herbs with narrow equitant 2-ranked leaves and perfect regular or 

 irregular mostly clustered flowers subtended by bracts. Perianth of 6 segments 

 or 6-lobed, its tube adnate to the ovary, the segments or lobes in two series, 

 convolute in the bud, withering-persistent. Stamens 3, inserted on the perianth 

 opposite its outer series of segments or lobes ; filaments filiform, distinct or united; 

 anthers 2-celled, extrorse. Ovary inferior, mostly 3-celled ; ovules mostly numer- 

 ous in each cell, anatropous ; style 3-cleft, its branches sometimes divided. Cap- 

 sule 3-celled, loculicidally dehiscent, 3-angled or 3-lobed (sometimes 6-lobed), 

 many-seeded. Seeds numerous, in I or 2 rows in each cavity of the capsule. 

 Endosperm of the seed fleshy or horny ; embryo straight, small. 



About 57 genera and iooo species, of wide distribution, in temperate and tropical regions of 

 both hemispheres. 



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



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



Style-branches 2-cleft ; plants bulbous. 2. Nemastylis. 

 Style-branches undivided ; plants not bulbous. 



Filaments all distinct; seeds fleshy. 3. Gemmingia. 



Filaments united ; seeds dry. 4. Sisyrinchium. 



i. IRIS [Tourn.] L. Sp. PI. 38. 1753. 



Herbs with creeping or horizontal, often woody and sometimes tuber-bearing rootstocks, 

 erect stems, erect or ascending equitant leaves, and large regular terminal sometimes pan- 

 icled flowers. Perianth of 6 clawed segments united below into a tube, the 3 outer dilated, 

 spreading or reflexed, the 3 inner narrower, smaller, usually erect, or in some species about 

 as large as the outer. Stamens inserted at the base of the outer perianth-segments; anthers 

 linear or oblong. 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. Capsule oblong or oval, 3-6-angled or lobed, mostly coriaceous. Seeds 

 numerous, vertically compressed, in 1 or 2 rows in each cell. [Greek, rainbow, referring to 

 the variegated flowers.] , 



About 100 species, mostly in the north temperate zone. Besides the following, some 8 others 

 occur in the southern and western parts of North America. The names Flower-de-luce and Fleur- 

 de-lis are applied to the species, many of which are in cultivation, and highly esteemed for their 

 beautiful flowers. Type species : Iris germanica L. 



Stems tall, usually several-flowered, leafy ; outer perianth-segments distinctly larger than the inner, 

 native species. 

 Flowers blue, variegated with yellow, white or green (rarely all white). 

 None of the perianth-segments crested ; native species. 

 Leaves yi'—i' wide. 



Leaves somewhat glaucous. i. /. versicolor. 



Leaves bright green, not glaucous. 



Outer perianth-segments 3'-4' long ; flowers sessile. 2. I. hexagona. 



Outer perianth-segments 2 yi'-z' long; flowers pedicelled. 



Capsule 3-angled ; seeds in 1 row in each cavity. 3. I. georgiana. 



Capsule 6-angled ; seeds in 2 rows in each cavity. 4. I.foliosa. 



Leaves much narrower, 2"-%" wide. 

 Capsule obtusely angled, 3-6-lobed. 



Capsule 3-lobed ; northern. 5. /. Hookeri. 



Capsule 6-lobed ; western. 6. /. missouriensis. 



Capsule sharply 3-angled. 7. /. prismatica. 



Outer perianth-segments strongly crested ; introduced and widely cultivated species. 



. 8. /. germanica. 



Flowers reddish or red-brown ; native species. 9. I.julva. 



Flowers bright yellow; introduced species. 10. I. Pseudacorus. 



Stems low, seldom over 6' tall, 1-3-flowered ; outer and inner perianth-segments nearly equal. 

 Outer perianth-segments crested ; leaves lanceolate. 



Perianth-tube very slender, exceeding the bracts. 11. I.cristata. 



Perianth-tube expanded above, not exceeding the bracts. 12. I.lacustris. 



Outer perianth-segments crestless, claws slightly pubescent ; leaves narrowly linear. 



13. /. verna. 



