FLORA OF THE DISTRICT OF COLUMBIA. 291 



42. ARNICA L. 

 1. Arnica acaulis (Walt.) B. S. P. Leopard's-bane. 



Sandy woods north and east of Washington and at Broadwater. May-Aug. South- 

 eastern U. S. (A. nudicaulis Ell.) 



A showy plant with large heads of yellow flowers and long yellow rays. 



43. ERECHTITES Raf. 



1. Erechtites hieracifolia (L.) Raf. Fireweed. 



Moist woods or fields. Aug.-Sept. Widely distributed in N. and S. Amer. 



A coarse annual with narrow heads of whitish flowers. It is often found in 

 burned-over areas, hence the common name. 



44. MESADENIA Raf. Indian plantain. 



Leaves glaucous beneath, the uppermost with a few large lobes. .1. M. atripliclfolia. 

 Leaves green beneath, the uppermost with numerous teeth 2. M. reniformis. 



1. Mesadenia atripliclfolia (L.) Raf. 



Woods; frequent. June-Sept. Eastern TJ. S. (Cacalia atripliclfolia \j.) 



2. Mesadenia reniformis (Muhl.) Raf. 



High Island, June 6, 1880 (Ward); probably now extinct. Eastern U. S. (Cacalia 



reniformis Muhl.) 



46. SYNOSMA Raf. 



1. Synosma suaveolens (L.) Raf. 



Low ground or damp woods along the Potomac; frequent. Aug.-Oct. Eastern 

 U. S. (Cacalia suaveolens L.) 



A tall glabrous perennial with triangular leaves and small heads of whitish flowers 



in corymbs. 



46. SENECIO L. 



A specimen of Senecio vulgaris L., an annual European species, was collected in 

 the Department of Agriculture grounds in 1873 ( Vasey). 



Basal leaves cordate at the base, about as broad as long 1 . S . aureus . 



Basal leaves not cordate at the base, rounded or tapering, often much longer than 

 broad. 



Basal leaves broadly obovate 2. S. obovatus . 



Basal leaves not obovate, rounded or oblanceolate-oblong. 

 Stem leaves lobed nearly or quite to the midrib; basal leaves oblanceolate- 

 oblong; stem very woolly at the base 3. S. smallil. 



Stem leaveB usually coarsely toothed, not lobed to the midrib; basal leave b 

 rounded; stem nearly or quite glabrous at the base 4. S. crawfordii. 



1. Senecio aureus L. Golden ragwort. 

 Damp woods and wet meadows; common. Apr. -May. Eastern N. Amer. 



2. Senecio obovatus Muhl. 



Reported from Great Falls by Greenman; 1 no specimens seen by the writer. East- 

 ern U. S. 

 8. Senecio smallii Britton. 



Thin woods and open fields; comnion. May-June. Pa. to Ala. (S. aureus bal- 

 samitae of Ward's Flora.) 



Two of our specimens were determined as 5. pauperculus Muhl. by Greenman, but 

 they seem not to differ from others determined as S. smallii. 

 4. Senecio crawfordii Britton. 



White gravel bog, southeast of Suitland. May. Pa., N. J., and Md. 



1 Ann. Mo. Bot. Gard. 3: 111. 1916. 



