150 Rhodora [Aueust 
acuta (Michx.) Herder, Act. Hort. Petrop. i. 428 (1872). Amarella 
acuta (Michx.) Raf. Fl. Tellur. iii. 21 (1836). A. plebeia (Cham.) 
Greene, Leaflets, i. 53 (1904). A. Amarella (L.) Cockerell, Am. Nat. 
xl. 871 (1906).— I am unable to discern any constant differences 
between the American and the European plant. The differences 
maintained by Grisebach all fail in a good series of specimens. Grise- 
bach’s statement, under G. acuta, was as follows: 
“This species is extremely like our G. Amarella; it seems, however, 
to differ constantly in the way the leaves embrace the stem. In 
G. Amarella the lamina of the two leaves ends at that point where they 
are affixed to the stem, so that they are separated from each other 
by an interstice formed by the stem; while in G. acuta the bases of 
both leaves touch each other without any interstice, so that the sub- 
stance of the leaves itself is somewhat connate: this character seems 
to be invariable throughout all those numerous forms in which these 
species are so rich; the upper leaves of G. acuta are, besides, always 
longer and more acute, and the leaves near the root are more or less 
spathulate, while in G. Amarella the leaves are always more equal in 
the same individual; the beard of G. acuta is longer and thinner, so as 
to disappear almost wholly here and there; the flowers are somewhat 
smaller; the calyx is shorter and more unequal; the stem more angular, 
and commonly almost winged. Besides, most of its forms are much 
stiffer, taller, and more branched; the stem often produces such 
slender and numerous branchlets from the under axillae as has been 
mentioned above of G. propinqua.” ! 
As stated, every one of these points urged by Grisebach fails, and 
many American specimens are closely matched in all details by Euro- 
pean specimens. 
Gray stated that var. acuta has the “crown usually of fewer and 
sometimes very few setae,” ? and Engelmann that it has 5-parted 
flowers while “The true European G. Amarella has usually 4-parted 
flowers”; but examination of plates of the European plant, if speci- 
mens are not available, quickly disposes of the latter point, for the 
European, like the American, has frequently 5-merous flowers. And 
the crown of nearly all American material is quite as fully developed 
as in the European; in fact most specimens have essentially identical 
crowns. 
‘ 
1 Grisebach in Hook. Fl. Bor.-Am. ii. 64 (1838). 
2 Gray, Syn. FI. ii. pt. 1, 118 (1878). 
3 Engelm. in Wheeler Exped. Rep. vi. Bot. 195 (1879). 
