Lactuca. COMPOSIT^E. 497 



L. villosa, Muhl.Jl. Lancaslr. ined. L. sanguinea, Bigel. ! fi. Bost. ed. 2. p. 

 134 ; DC. I. c. Galathenium sanguineum, Nutt. ! in trans. Amer. phil. soc. 

 I. c. G. Floridanum, Nutt. ! I. c, fide herb. acad. Philad. 



e. alhijlora: glabrous, " flowers white" ; otherwise as in var. y. 



Rich damp soils, fields and borders of thickets, Canada ! and Saskatcha- 

 wan! to Georgia! and Louisiana! y. Massachusetts! and Upper Mis- 

 sissippi ! to Louisiana ! and Texas ! in more exposed places and sterile soil. 

 <5. Western Louisiana, Dr. Hale ! July-Aug.— (f) ? Stem 2-8 feet high, 

 hollow. Leaves mostly large, very variable ; all the above varieties pass- 

 ing into each other. — Wild Lettuce. Fire-weed. 



X Doubtful species. 



3. L. Ludoviciana (DC. 1. c.) : very smooth (3-5 feet high); leaves all 

 runcinate, retrorsely and sharply toothed ; the cauline partly clasping ; panicle 

 divaricate, the peduncles and involucre naked ; pappus conspicuously stipitate ; 

 flowers yellow, ISutt. — Sonchus Ludovicianus, Nutt. gen. 2. p. 125. Gala- 

 thenium Ludovicianum, Nutt. in trans. Amer. phil. soc, as to syn. 



Moist places in the open plains around Fort Mandan on the Missouri, Nutt- 

 all. June. — This is entirely unknown to us. May it not be a state of the 

 polymorphous Lactuca elongata? But a specimen in the herbarium of the 

 Academy of Natural Sciences at Philadelphia (New Orleans, Mr. Trudeau!) 

 ticketed by Mr. Nuttall ' Mulgedium Ludovicianum', is M. Floridanum, 

 wanting the lower leaves. 



L. Canadensis (Linn. 1. c), as to the description, and especially as regards the 

 syn. " L. Canadensis altissima angustifolia, flore pallide luteo.'' Town. inst. p. 474, 

 (which is perhaps the foundation of the species) probably relates to the common 

 Lactuca elongata; to which, indeed, the very imperfect specimen in the Linnaean 

 herbarium may belong, although it is marked by Smith as a Sonchus. 



198. MULGEDIUM. Cass. diet. 33 (1824), p. 296 ; Less. syn. p. 142 ; DC. 

 Agathyrsus, Don (1829). 



Heads many-flowered. Involucre calyculate-imbricated ; that is, with the 

 exterior scales much shorter than the others and more or less imbricated. 

 Receptacle naked, foveolate. Achenia glabrous, compressed, striate with a 

 few nerves or ribs on each side, the summit contracted into a more or less 

 evident thickish beak of the same texture with the body of the achenium, which 

 is expanded at the apex into a ciliate disk. Pappus of copious somewhat 

 scabrous capillary bristles in one or more series, rather soft and deciduous, 

 either bright white or tawny. — Caulescent herbs (mostly of the northern he- 

 misphere) ; with pinnatifid or undivided leaves, and racemose or usually 

 paniculate heads. Flowers blue, rarely dull bluish-white or ochroleucous. 



§ 1. Pajtpus bright white: corolla blue or purple. — Eumulgedium, DC. 



* Achenia tapering into a slender beak : involucre imbricated. 



1. M. pulchellum (Natt.): glabrous, pale or glaucescent; stem simple or 



sparingly branched; leaves oblong-lanceolate or linear, sessile, mucronale, 



entire, or lower runcinate-pinnatifid ; heads several, racemose-corymbose ; 



the erect peduncles furnished with subulate scale-like bracteoles; scales of 



vol.. II. — 63 



