1908] Fernald,— Bidens connata and its American Allies 199 
species. ‘This character, however, proves to be very inconstant in 
B. connata and B. petiolata, warty or smooth achenes occurring on 
plants with either type of foliage; and very often the immature achenes 
of the younger heads are smooth while those of the older heads are 
distinctly warty. In all these plants the faces of the inner achenes 
are prominently ribbed making the achenes 4-angled, and the awns 
are 4 in number, while the 3-angled outer achenes usually have 3 
awns. ‘There is, futhermore, great probability that the smooth- 
fruited American specimens with which recent German botanists have 
contrasted the warty-fruited B. connata are not of this species but are 
B. comosa (Gray) Wiegand (a species which long passed in American 
collections as В. connata), for, as stated by Dr. Warnstorf, in the 
American plant with which he was contrasting his Neuruppin material 
"the fruits are always smooth and usually two-awned, only occa- 
sionally having a shorter median awn"; while Professor Ascherson, 
writing to Dr. Robinson in 1898, stated that the so-called B. connata 
examined from America had the outer bracts of the involucre “6-8 
or more" and "achenia smooth, ribs less prominent [than in the 
Neuruppin В. connata], awns 2-3"; all of which characters belong to 
the American В. comosa rather than to B. connata. ‘The conclusion 
is, then, that in B. connata the presence or absence of warts and the 
degree of their development are characters which are not concomitant 
with the marked differences of foliage. 
As already noted by Professor Wiegand, the plant with short broad 
petioles is commoner in New England while the slender-petioled form 
is more general westward. Yet the plant with three-lobed leaves 
(typical B. connata) has apparently been found in Michigan, for in his 
Flora of Detroit, Mr. O. 4. Farwell, obviously ignoring both Muhlen- 
berg's and Nuttall's descriptions, makes the following singular dis- 
position of the plants. 
1“ Meanwhile, my long-time friend Professor Dr. Ascherson of Berlin, who had become 
interested in the plant [from Neuruppin, Germany] made an examination of the Berlin 
Botanical Museum and referred our plant, by Mühlenberg's type specimen, in Willde- 
now’s herbarium under no. 15,021, to B. connatus. The matter would have been thereby 
settled had I not already received from various parts of North America as B. connatus 
an entirely different plant. In this the fruits are always smooth and usually two-awned, 
only occasionally having a shorter median awn. They are, thus, just like those of B. 
tripartitus. On this account the specimens from the United States heretofore seen by 
me cannot possibly be identified with Mühlenberg's type in the Willdenow herbarium, 
but belong to another good species." — Warnstorf, Bot. Gaz. xxv. 48 (1898). 
2“In New England the leaves are shorter petioled, while in the West the petioles are 
often very long (1 cm.) " — Wiegand, Bull. Torr. Bot. Cl. xxvi. 415 (1899). 
