IOWA ACADEMY OF SCIENCES. 
109 
PRICKLY LETTUCE. 
Lactuca Scarolce, L. 
Description. An annual or winter annual, pale green 
’glabrous; the lower part of the stem has soft prickles; 
leaves four to six inches long, vertical because of the twisting, 
lanceolate to oblong with a row of soft spinulose denticulate 
prickles on the margins, occasionally sinuate toothed, some- 
times pinnatifid. Midrib beneath beset with soft prickles; base 
of leaf sagittate, clasping. Heads in an open panicle, 10 — 18 
flowered, flowers pale yellow; beak of fruit as long as the 
.akene, the latter being striate nerved. Pappus slender of capil- 
lary bristles arranged like a parachute. 
It took twenty -one years for Prickly lettuce to become com- 
mon. It was first observed near Hovey’s Garden in 1863-64. 
From 1863-1894 it was reported from Ohio, Illinois, ¥/isconsin, 
and other states. 
During the past summer much interest has been manifested 
on the appearance of this weed in many localities, so much so 
that Prof. Morrow, of Illinois, issued a j)ress bulletin, and Dr. 
J. C. Arthur an extended account of this weed\ It would be 
almost superfluous to publish more on the distribution of this 
weed, as Dr. Arthur has such a full and excellent account, but 
-it may not be out of place to bring the localities together, 
collectively, along v/ith the other weeds of this pa|3er. Dr. Gray 
.{Synoptical Flora of North America, Vol. I, pt. II, p. 442), 
makes this statement: Waste ground becoming common in 
Atlantic states near towns and habitations. 
Idaho. — Sweet 1894 (Thomas J. Coonrad). Moscow. Per- 
nicious weed in northern part of state, 1894 (F. L. Henderson). 
Blackfoot; August, 1893 (Edward Palmer). Blue lakes, August, 
.1893, (Dr. Edward Palmer). 
Illinois. — First saw a few specimens in 1884, is now com- 
mon everywhere. (Brendel). 
Cook county, “Roadsides and dooryards, infrequent, 1891.” 
>' (Higley and Raddin, ‘ ‘The Flora of Cook County, Illinois, and 
. a part of Lake County, Indiana. Bulletin, Chicago Academy 
of Science, Vol. II, No. 1, p. 71). 
Evanston, 1883, (C. S. Raddin), catalogue of the Phsenogam- 
‘ Ous Plants of Evanston and Vicinity for 1883, p. 15). 
Chicago. Roadsides and dooryards everywhere, 1893. (Pam- 
;mel.) 
iWild or Prickly lettuce. Bulletin No. 52, Vol. V, Nov., 1894. 
