44 ASTERACEAE 



Sonchus — Sow-thistle 



(Gr. name of the sow-thistle) 



1. Perennial; heads 2-3 cm. wide S. arvensis 



2. Annual 



a. Achenes wrinkled crosswise; ears of leaves acute S. olerdceus 



b. Achenes 3-striate on each side ; ears rounded 5". dsper 



Lactuca — Lettuce 



(Lat. lactuca, lettuce, from lac, milk, referring to the miiky juice) 



1. Pappus white 



a. Flowers '.due L. pulchella 



b. Flowers yellow or cream-colored 



(1) Cultivated L. saiiva 



(2) Native 



(a) Leaves twisteu into a vertical position, midrib spiny L. scariosa 



(b) Leaves normal, pinnatifid ; margin spiny L. ludovicidna 



2. Pappus brown L. spicdia 



Hieracium — Hawkweed 



(Gr. hieracium, hawkweed, from hierax, hawk) 



1. Leaves and stem with hairs 2-3 cm. long; achene long-beaked II. longipilutn 



2. Leaves and stem with short stout hairs; achenes truncate II. scdbrum 



Crepis — Hawksbeard 



(Gr. krepis, boot, base, perhaps from the basal rosette) 

 Leaves lanceolate, pinnatitid ; heads yellow C. tectorum 



Nabalus — Nabalus 



(Latinized form of the Indian name) 



1. Pappus dark brown N. dlbus 



2. Pappus straw-color 



a. Involucre hairy N. dsper 



b. Involucre smooth N. altissimus 



Cichorium — Chicory 



(Latinized form of the Arabic name) 

 Leaves lobed ; heads blue C. intybus 



Monocotyledons 

 Alismales Arrowhead Order 



Alismaceae— Arrow-head Family 

 Aquatic and marsh herbs, with fibrous roots, flowers in clusters; sepals 3, not petal-like, petals 3, 

 stamens 6-many, pistils several-many; flowers apocarpous, apopetalous, hypogynous, regular. 



1. Each pistil 1-seeded 



a. Flowers perfect ; pistils in a ring Alisma 



1). Pistillate and staminate flowers separate; pistils covering a convex 



receptacle Sagiltaria 



2. Each pistil many-seeded 



a. Stamens 9, fertile Butomus 



b. Numerous fertile and sterile stamens Hydrocleis 



Alisrria — Water-plantain 



(Gr. alisma, a water plant) 

 Native plant with ovate leaves, and many small flowers in an upright panicle A. planlago-aqudtka 



Sagittaria — Arrow-head 



(Lat. sagitta, arrow, from the shape of the leaves) 

 spei ies, mostly blooming in midsummer 



1. Leaves arrow-shaped; pistillate flowers obviously stalked S. latifolia 



2. Leaves linear, ovate, or rarely arrow-shaped; pistillate flowers not 



stalked S. rigida 



