Jennings: The Genus Lactuca. 441 



described Mulgedium leucophccum " ad margincs sylvaruni Amcr. bar. 

 a Novd-Anglia ad Virginiam (Pursh), ad Laciim Huron (Hook.)."- 



In an examination of about twenty descriptions of Lactuca spicata 

 as placed by various authors under the genus Sonchus, Mulgedium, or 

 Lactuca, only four references were found giving the color of the 

 flowers as yellow or yellowish. The descriptions in by far the greater 

 number of the manuals and floras of the eastern United States have 

 been drawn very largely from material collected and studied along the 

 eastern coastal regions; this being, of course, especially true of the 

 earlier systematic works, when practically nothing was known of the 

 flora in or beyond the Appalachians. In this connection it is of in- 

 terest to note that in some of the earlier systematic works where 

 Lactuca spicata was known only from the region quite closely ad- 

 jacent to the Atlantic coast the plant is always described as having 

 blue or white flowers.' As the species became somewhat better 

 known, and its known range was extended into the interior, a few 

 of the descriptions indicated the flowers as ranging in color from blue 

 to yellow,* while Wood, in his valuable Class-Book, described the 

 flowers only as " yellowish." ° 



A further examination of the evidence furnished by the various 

 " floras " and " manuals " indicates that in the New England States 

 and along a comparatively narrow strip bordering the Atlantic coast 

 the flowers of Lactuca spicata are blue to white, while to the south- 

 west and west the flowers become more or less completely yellow. 

 That the line of demarcation between these regions is perhaps quite 

 sharp is not unlikely. In the more recently published Flora of Phila- 

 delphia and Vicinity*^ the flowers are referred to as blue to white, 

 while in Darlington's Flora Cestrica we have " Florets pale blue, or 

 ochroleucous." Small and Carter in their Flora of Lancaster County 

 [Pennsylvania] say for Mulgedium spicatum: " ligules white, yellow- 

 ish, or bluish." " From the foregoing and from such facts as the 



- De Candolle, A. P., Prodromus Systematis Naturalis Regni Vegetabilis, 

 VII, 1838, p. 250. 



3 Eaton's Manual, Chapman's Flora, Pursh's Flora, Torrey's Flora. N. Y., etc. 



4 Noll, H. R., Flora of Pennsylvania, 1852; Small, J. K., Flora of the 

 Southeastern U. S. ; Darlington, Wm., Flora Cestrica, 1853. 



5 Wood, A., Class-Book of Botany, 18S0, etc. 



G Keller, I. A., and Brown, S., Handbook of the Flora of Philadelphia and 

 Vicinity, 1905. 



'Small, J. K.. and Carter, J. J., Flora of Lancaster County, 1913. 



