Lactuca. COMPOSITE. 441 



* Scapose, monoceplmlous, perennial \>y roundish tubers. 



P. SCapOSUS, DC. 1. c. Ilirsutulous-pubescent, low and simple : globular tuber (three- 

 fourths inch in diameter) sending up a slender caudex, bearing at the surface of the ground 

 a cluster of pinna tifid leaves and scapes of a span or two high : the latter simple and naked, 

 sometimes a bract or small leaf near the base : head seldom an inch high in fruit : calyculate 

 bracts of involucre short and small, subulate ; principal ones obscurely corniculate at tip; 

 flowers citron-yellow : pappus fulvous. P. grandiflorus, Nutt. Trans. Am. Phil. Soc. I.e. 

 430; Torr. & Gray, 1. c. ; Engelm. &, Gray, PI. Lindh. i. 42. Barkhuusia (jmndi flora, Nutt. 

 Jour. Acad. Philad. vii. 69. Prairies of Arkansas and Kansas; first coll. by Pitcher. 

 Texas; first coll. by Berlandier. 



* * More or less leafy-stemmed and branching: heads moderately long-pedunculate. 

 -1 Leaves diversely pinnatifid, laciniate, sinuate-dentate, or some upper ones entire. 



P. Carolinianus, DC. Annual or biennial, freely branching, 2 to 5 feet high, nearby 

 glabrous, but peduncles and involucre mostly ciuereous-puberulent : upper leaves when undi- 

 vided usually elongated lanceolate and gradually attenuate to the tip : flowers very bright 

 yellow: fruiting heads fully inch high: calyculate bracts setaceous-subulate, loose, half or 

 a third the length of the principal ones ; these conspicuously corniculate at the apex : 

 pappus rufous. Torr. &, Gray, 1. c. ; Nutt. Trans. Am. Phil. Soc. 1. c., with var. inaximns. 

 P. multicaulis, Curtiss, Distrib. N. Am. PI. 1623, not DC. Leontodon Carolinianum, Walt. 

 Car. 192. Scorzonera pinnatifida, Michx. Fl. ii. 89. Chondrilla Ueriyalu, Pursh, Fl. ii. 497. 

 Barkhnusia Caroliniana., Nutt. Gen. ii. 126; Ell. Sk. ii. '251. Dry ground, Maryland to 

 Florida, Arkansas, and Texas. 



P. nmlticaulis, DC. 1. c. A foot or two high from a thickened apparently perennial root 

 (but flowering first season), less leafy, at length many-stemmed from base and diffuse or 

 ascending : leaves seldom large: head in fruit two-thirds to three-fourths inch high: calycu- 

 late bracts of involucre short and subulate : pappus rufous or fulvous. Texas (first coll. by 

 Berlandier), New Mexico (Newberri/, Greene, liitshi/), and Arizona (Lc.mmon), the latter a 

 dwarf and very narrow-leaved form: (Mex., where P. pauciflorus aud even P. Scsseanus 

 are probably forms of it.) 



-i 4 Leaves all undivided, narrow: stems junciform. 



P. Rotlirookil, GR.VY. Glabrous, or involucre obscurely puberulent : stems 1 to 3 feet 

 lii^'h, slender, erect from a thickened perennial root : leaves narrowly lanceolate or linear, 

 entire or merely denticulate (3 to 9 inches long, 1^ to 4 lines wide) ; radical ones spatulate- 

 lanccolate : calyculate bracts of involucre short and subulate : head iu fruit only two-thirds 

 inch high : pappus sordid-whitish. Proc. Am. Acad. xi. 80; Kothrock in Wheeler Rep. vi. 

 101, t. 14. Mountains of S. Arizona, Ilothrock, Lcmmon. 



233. CHONDKiLiIjA, L. (Name by Dioscoriclcs, of unexplained mean- 

 ing, for some gummiferous plant.) Old World herbs, perennials or biennials ; 

 with virgatc or rush-like stems and branches, leafy below, and small heads of 

 yellow flowers ; one species introduced. 



C. JUNCEA, L. Hirsute towards the base, 1 to 3 feet high, glabrous above : lower leaves runci- 

 uate ; upper linear and entire, those on the long slender branches reduced to linear-subulate 

 bracts : heads scattered or in small clusters and nearly sessile along the branches : akenes 

 somewhat clavate, bearing a circle of scales at base of the filiform beak. Old fields and 

 banks, S. Maryland and N. Virginia, common about Washington. (Nat. from Eu.) 



234. LACTtJCA, Tourn. LETTUCE. (Ancient Latin name, from lac, 

 milk, referring to the milky juice.) --Mostly tall herbs (of the northern hemi- 

 sphere) ; with leafy stems, and paniculate middle-sized or small heads of yellow, 

 blue, or sometimes whitish flowers, in summer. Involucre in ours glabrous and 

 smooth. --Benth. & Hook. Gen. ii. 524, excl. 5, 6. Lactuca & Mulgedium^ 

 Cass., DC., &c. 



