Jan., 1902 .] 
Botanical Correspondence. 
1 89 
The full title is as follows : Manual of the Flora of the 
Northern States and Canada, by Nathaniel Lord Britton, Ph. D. 
The author is the director-in-chief of the New York Botanical 
Garden and Emeritus Professor of Botany in Columbia Univer- 
sity. The publishers are Henry Holt & Co., New York, and the 
price is $2.25. 
Item 8 . A beginner asks, ‘, what a double citation of authors 
signifies”; he wishes to know also the reason for occasional 
“ duplication of a generic name ” for the species. Examples of 
the two cases, taken at random, are as follows : 
1. Grape B'ern ; Botrycliium virginianum (L.) Sw. 
2. Marsh Muhlenbergia; Muhlenbergia racemosa (Mx.) B. S. P. 
3. Kentucky coffee tree ; Gymnocladus dioicus (L.) Koch. 
4. Upland white Aster; Aster ptarmicoides lutescens ( Hook.) 
Gr. 
5. Indian mallow; Abutilon abutilon (L.) Rusby. 
6. Dandelion; Taraxacum taraxacum (L.) Karst. 
In brief explanation of the above the following may be stated: 
1. Linnaeus named this plant Osnninda virginiana, but it is 
not an Osmunda as that genus is now understood, and Swartz 
placed it in the genus Botryehium. 
2. Muhlenberg placed this grass in the genus Agrostis, with 
the name Agrostis racemosa, and it was afterwards changed to 
its proper place by Britton, Stearns and Poggendorf. 
3. The Kentucky coffee tree was first given a botanical name 
in 1753 by Linnaeus ; then when the genus Gymnocladus was 
proposed the plant was rechristened Gymnocladus canadensis (a 
name used in Gray’s Manual) by Lamarck in the year 1783 ; the 
first specific name was restored — according to the rule of priority 
now generally recognized by naturalists — by Koch in 1869. 
4. This variety of aster was named by Hooker as Diplopappus 
albus var. lutescens ; then Torrey and Gray placed it in the 
genus Aster with the specific mime A. lutescens, and Gray sub- 
sequently published it as Aster ptarmicoides var. lutescens, hence 
the citation as given in the later publications. 
5. The Indian mallow was first enumerated by Linnaeus as 
vSida abutilon in 1753, in his Species Plantarnm. The genus 
Abutilon was published by Gaertner in 1791. This plant is an 
Abutilon as botanists interpret that genus ; it was only lately 
(1894) that Dr. Rusby restored the original specific name, which 
is abutilon, but the fact that it is similar in form to the now 
recognized generic name does not invalidate it in the opinion of 
most American botanists. 
6. The Dandelion was given in Linnaeus’s Species Plantarum 
as Leontodou taraxacum, 1753; then Weber named the plant 
Taraxacum officinale, 1780; later Desfontaines called it Taraxa- 
cum dens-leotiis, 1800; it was Karsten, 1883, who properly 
restored the original specific name, this being the same in form as 
the generic name long since recognized by all botanists. 
