126 CONTRIBUTIONS FROM THE NATIONAL HEEBAEIUM. 



31. IRIDACEAE. Iris Family. 



This family contains many ornamental species in common cultivation, Crocus, 

 Freesia, and Gladiolus being well-known genera. Species of Crocus tend to persist in 

 old lawns and gardens. 



Flowers large, more than 4 cm. long; leaves broad. 

 Flowers yellow or blue; seeds dry; style branches opposite the anthers, broad, petal- 

 like - 1. IRIS. 



Flowers orange; seeds fleshy; style branches alternate with the anthers, slender- 

 filiform 2. GEMMINGIA. 



Flowers small, less than 2 cm. long; leaves grasslike. Style branches alternate with 

 the anthers, filiform , . .3. SISYBINCHIUM. 



1. mis L. 



Stems tall, leafy, usually several-flowered, more or less branching; perianth tube much 

 shorter than the sepals, these larger than the petals and not crested. 



Flowers blue 1. I. versicolor. 



Flowers yellow 2. I. pseudacorus. 



Stems low, 20 cm. high or less, 1-3-flowered; perianth tube long and slender, the violet- 

 blue sepals and petals nearly equal. 



Leaves lanceolate; sepals crested 3.1. cristata. 



Leaves linear; sepals not crested 4.1. verna . 



1. Iris versicolor L. Blue flag. 

 Open swamps and bogs. May. Eastern N. Amer. 



The flowers are shown in plate 19B. 



2. Iris pseudacorus L. Yellow flao. 

 Established along the Potomac marshes below Washington. May. A local escape 



from cultivation throughout the eastern U. S. ; native of Eur. 



3. Iris cristata Ait. Crested iris. 

 Stream margins and low wet woodland; along the Potomac above Washington; rare. 



May. Southeastern U. S., north to Md. 

 A plant in flower is shown in plate 15B. 



4. Iris verna L. Spring iris. 

 Dry sandy woods near swamps; locally abundant in one or more localities, Bladens- 



burg to Ammendale. May. Southeastern U. S., north to Pa. 



Many cultivated species and hybrids of 7m are found in gardens. I. germanica L. 

 and others tend to persist in old gardens and dumps. 



2. GEMMINGIA Fabr. 

 1. Gemmingia chinensis (L.) Kuntze. Blackberry lily. 



Escaped from cultivation along roadsides and fences, preferring rich, well-drained 

 soil. July. Naturalized from Asia in the eastern U. S. {Pardanthus chinensis Ker.) 

 When the capsule dehisces the mass of black fleshy seeds suggests a large black- 

 berry. 



3. SISYRINCHniM L. Blue-eyed grass. 



Stems simple, with a terminal sessile spathe, narrowly wing-margined, drying green. 



1. S. mucronatum. 

 Stems branched, or if simple broadly winged. 

 Stems broadly winged. 



Stems either simple or branched; plants drying green 2. S. intermedium. 



Stems branched above, bearing two or more pedicellate spathes; plants darken- 

 ing in drying. Pedicels spreading or recurved 3. S. gramineum. 



Stems narrowly winged; pedicels not recurved; plants not darkening in drying. 



4. S. atlanticum. 



