FLORA OF WASHINGTON AND VICINITY. 93 



tKiigia Virginica, Willd. Dwakf Dandelion. 



April to June. 



t Cynthia Dandelion, DC. IKrigia, Benth. & Hook., Gen. PI.] Dandelion Cynthia. 

 Second and third weeks in May. 



tHieracium scabrum, Micbx. Eough Hawk- weed. 

 September. 



tHieracium Gronovii, L. Hairy Hawk-weed. 



A form occurs liaving the panicle of H. vensosum but the achenia of H. Gronovii. 

 August, September. 



tHieracium venosum, L. Rattlesnake-weed. 

 Latter part of May. 



Hieracium venosum, L., var. subcaulescens, Gray. 

 Roach's Run, above the Long Bridge. May 19, 1878. 



tHieracium paniculatum, L. PiVNiCLED PIawk-weed. 



Left bank of Rock Creek above the Ford ; rare. Early part of September. 



tTaraxacum Dens-leonis, Desf. Common Dandelion. 



Flowers the year round unless very cold or very hot and dry. 



ChondrillajMwcea, L. 



Recently introduced, but now becoming abundant everywhere. July. Radical 

 and stem leaves should be collected in May. 



tliactuca Canadensis, L. Wild Lettuce. * 



June to August. 



Lactuca Canadensis, L., var. integrifolia, Torr. & Gray. 

 July, August. 



Mulgedium acuminatum, DC. [Lactuca, Benth. & Hook., Gen. PI.] False Let- 

 tuce. Blue Lettuce. 



Rock Creek. Less common than the next. August, September, 



t Mulgedium Floridanum, DC. 



August, September. 



Mulgedium leucophaeum, DC. 



Bladensburg (Professor Chickering. ) 



tNabalus albus, Hook. {_Prenanthes, Benth. & Hook., Gen. PI.] White Lettuce. 

 Rattlesnake-root. 

 September. 



TNabalus Fraseri, DC. Lion's-foot. Gall-of-the-eakth. 



Sejitember. 



t Sonchus oZeracews, L. Common Sow- Thistle. 

 June. 



Sonchus asper, Vill. Spiny-leaved Sow-Tiiistle. 

 June. 



