Xasthium. COMPOSITiE. 295 



more or less incurved beaks ; stem and petioles rough and strigose, spotted ; 

 leaves scabrous, broadly subcordate, obtuse, irregularly repand-toothed, ob- 

 scurely lobed.— Murr. coiiim. Gull. 6 (1783-S4) ^?. 32, ^. 4 (good figure) ; 

 Willd. spec. 4. ^;. 374. X. maculatum, Raf.! in Sill. jour. 1. p. 151. 

 X. orientale, Muhl. cat. p. 89 ; Nutt. gen. 2. p. 186 ; Torr. ! cat. pi. New 

 York, p. 73 ; not of Linn. X. macrocarpon, DC! p)rodr. 5. p. 523, in 

 part ; Beck, hot. p. 210. 



p. prickles of the oval-oblong fructiferous involucre stouter and less crowd- 

 ed ; leaves incisely lobed. 



Waste places near salt water, Massachusetts! and New York! to Caro- 

 lina! /3. Banks of Spirit Lake, head-waters of the Little Sioux River of 

 the Missouri, Mr. Nicollet ! Aug.-Oct. — A stout and very coarse plant, 1-2 

 feet high. Mature fruit about an inch and a quarter long, turgid, three- 

 fourths to nearly an inch broad, including the slender but rigid recurved- 

 spreadins prickles with which it is very densely invested, and which, as well 

 as the beaks, are clothed with rigid bristly hairs. This is certainly different 

 from the X. macrocarpon, DC, which has an oblong fruit with very stout, 

 suberect and scattered ])rickles. Murray's plant was raised from seeds col- 

 lected at New York by Wangenheim. We have never met with it at a dis- 

 tance from the sea-coast, except the specimens of var. /?., which are, how- 

 ever, from a region which abounds in salt marshes. These indeed approach 

 X. macrocarpon, and may prove to belong to tliat species ; but they are ap- 

 parently in a stunted state. 



§ 2. Leaves narrowed into the petiole, furnished with spines at their base : 

 frucliferous involucre with a single beak. — Acanlhoxanthium, DC. 



3. X spinosum (Linn.) : spines at the base of the leaves 3-parted, slender; 

 stem much branched ; leaves ovate-lanceolate, cuneate at the base, entire or 

 somewhat 3-lobed, with the middle lobe prolonged, acuminate, the lower 

 surface and the veins of the upper canescent ; involucre cylindrical-oblong, 

 with an inconspicuous beak ; the prickles slender. — Linn. spec. [ed. 2) 2. 

 p. 1400,- Lam. ill. t. 655, /. 4 ; Ell. sk. 2. p. 479 ; DC! prodr.5. p. 523. 



Naturalized in many places along the coast from Massachusetts ! to Geor- 

 gia ! Sept.-Nov. — Heads few, or solitary and sessile in the axils. Spines 

 yellowish. 



Subtribe 2. Heliantheje, Less. — Heads heterogamous and radiate, 

 rarely homogamous and discoid ; the disk-flowers perfect. Receptacle 

 chaffy. Lobes of the corolla in the perfect flowers often somewhat thickened 

 and papillose. Anthers blackish, not caudate at the base. Pappus either 

 wanting, or coroniform, or of awns which are sometimes chaffy or with chaffy 

 scales intermixed, never of capillary bristles, nor of several uniform and dis- 

 tinct chaffy scales. — Leaves commonly opposite. 



CONSPECTUS OF THE GENERA. 



Div. 1. Heliopside^. — Rays fertile, rarely none. Aclienia with a thick outer 

 integument, not obcomprcssed. 



83. Melanthera. Rays none. Pappus of few rigid caducous bristles. 



84. Zinnia. Rays persistent. Pappus 1-2-awned, persistent. 



85. Wyethia. Rays numerous. Pappus coroniform-tootlied and 1-3-awned. 



