150 MISSOURI BOTANICAL GARDEN. 
obtained from the root bark of Alkanna tinctoria which is 
cultivated in South and Central Europe for the dye which 
is used in pharmacy for coloring salves, and for coloring 
wine and other liquids sold as wine. Alkanet is also an 
excellent test for resins and oils, to which it gives a red 
color, and is used in microchemistry as a reagent for these 
substances. The dye is said to give a brilliant violet color 
with iron and alum mordants to linen, cotton and silk, 
but not to wool. The fact that the wool on sheep grazing 
among growing plants is colored is probably due to the 
alkannin being dissolved in the oil of the wool. In the old 
world alkannin occurs also in quantity of commercial value 
in Arnebia, Echium, Symphytum, Onosma and Lithosper- 
mum .* 
In a brief examination I have found but a few references 
to this color in American Borraginaceae. The color in the 
roots of species of Lithospermum (the puccoon of the 
Indians) is well known; and Dr. Gray in the Synoptical 
Flora, mentioned one species of Plagiobothrys (P. 
Torreyi), the herbage of which “ gives an abundant 
violet stain to paper.’’ It is opposed in this character to 
P. ursinus of similar habit, but « imparting no violet stain 
topaper.”” P. tinctorius (Ruiz & Pavon) Gray, Proc. 
Am. Acad. 20: 283, of South America, is also described as 
‘* papyros violaceo colore tingens.’’ 
An examination of the herbarium material of the Garden 
shows that the coloring matter is abundant enough to stain 
the herbarium paper in the following species, chiefly in the 
roots: Hchium vulgare, Eritrichium glomeratum, Kry- 
nitzkia barbigera (abundant in leaves), HK. Californica 
(slight), A. maritima, K. micrantha, K. pterocarya, 
Lithospermum multiflorum, L. strictum, L. spathulatum, 
L. hirtum, L. canescens, L. angustifolium (not abundant ), 
Plagiobothrys canescens (in leaves), P. nothofulvus (in 
leaves), P. tenellus, P. Arizonicus (abundant in stem and 
* Engler & Prantl, Pflanzenfamilien 4%: 73, 118, 124, 127. 
