COMPOSITE 

 LACTUCA SATIVA (Garden Lettuce) 



629 



Description. — Common garden lettuce is a tall, annual 

 leafy herb, with a milky juice. There is thrown up from 

 a short stem early in the season a cluster of leaves varying 

 considerably in shape, character, and color, in the different 

 varieties. Later in the season, a "seed stalk" is sent up. 

 Tracy found that, at Washington, D. C, the first appearance 



Fig. 255. — Asparagus lettuce, var. angustana. (After CorbeU.) 



of the seed stalk after sowing seed, varied from 59 (in 

 Emperor Forcing) to 112 (in Italian Ice) days. The leaves 

 are alternate, denticulate or pinnatifid, sessile or auriculate- 

 clasping, sometimes spinulose-margined, the lowest ones 

 large, and the upper much smaller. The inflorescence is a 

 panicle. The flowers are yellowish or yellowish-white, the 

 involucre cylindric, the bracts of which are imbricated in 

 several series, the outer shorter. The receptacle is flat and 

 naked. The corolla rays are truncate and five-toothed at 



