} 
1911] Bartlett, — Euphorbia arundelana 163 
EUPHORBIA ARUNDELANA, AN ALLY OF EUPHORBIA 
IPECACUANHAE. 
Harvey Harris BARTLETT. 
Dr. MILLSPAUGH has said that “the singular and extremely amor- 
phous” Euphorbia Ipecacuanhae “represents in itself seven ‘ Rafines- 
quian species,’ so greatly does it vary in form, color, inflorescence and 
leaf." No one who has seen the plant in nature will dispute the 
statement. 'The leaves vary from linear to broadly ovate, and 
between two plants of the same leaf shape, growing in the same square 
foot of soil, there is often a difference of several hundred percent in 
the size of the leaves. Some plants are entirely purple, some pale 
green, in others the purple pigment is definitely localized in certain 
organs. A colony of Euphorbia Ipecacuanhae consists of a host of 
forms, different enough from one another so that they can be assembled 
into groups of like individuals. De Vries! believes that the species 
is in a mutable condition. 
In the western part of Anne Arundel County, Maryland, there is a 
close ally of Euphorbia Ipecacuanhae, seemingly undescribed, which 
may be called Euphorbia arundelana. Both species grow together 
in a small area (equidistant from the bridges which cross the Patuxent 
River to Laurel and Bowie, Prince George's County) designated as 
“ Sassafras fine sandy loam” ? on the U. S. Soil Survey sheet of Anne 
Arundel County. 
The essential and striking character of Euphorbia arundelana is 
1** Herr Dr. J. W. Harshberger sandte mir Material von Hibiscus Moscheutos und 
Euphorbia Ipecacuanha aus Pennsylvania, welches durch den auffallenden Reichthum 
an Formen auf eine Mutationsperiode für diesen Arten schliessen lüsst." De Vries, 
Die Mutationstheorie, II, p. 664. 
? This soil type is a brownish or deep yellow sandy loam, heavy at the surface, but 
lighter in color and texture as the depth increases. ''At 26 to 30 inches it passes into 
a sand or loamy sand varying in color from a light yellow to a reddish brown.... 
The loose open character of the subsoil allows excessive moisture to pass readily 
through it, while at the same time the texture of the soil gives it a good water-holding 
capacity.... The material composing the soil is a marine sediment washed down from 
the higher lands farther north....The particles are sharp and angular, indicating 
that the soil has not been water-worn to a great extent....The Sassafras fine sandy 
loam occurs principally in the southern and western parts of the country....It is 
found at elevations ranging from 40 to 150 feet above tide." J. C. Britton and C. R. 
Zappone, Soil Survey of Anne Arundel County, Maryland. (Advance Sheets — 
Field Operations of the U. S. Bureau of Soils, 1909.) 
