1909) Sargent,— American Crataegi of Linnaeus 183 
glabrous and the pedicels are slightly hairy; and it cannot, as Mr. 
Eggleston has suggested, represent Crataegus modesta. "е specimen 
is thornless and the detached thorn in the Plukenet figure may have 
been taken from one of the two other specimens in the Plukenet Her- 
barium which the same unknown person has referred to the plant 
figured on t. 46, f. 4. The thorns on one of these specimens are 
slightly thicker and on the other they are more recurved than that 
figured by Plukenet. ‘These three specimens in the Plukenet Herba- 
rium referred to t. 46, f. 3, certainly all represent different species either 
in the Molles or Lobulatae Groups, and I am unable to identify any 
of them. ‘The matter is further confused by the fact that Linnaeus 
also referred to his Crataegus coccinea the plant figured in the Hort. 
Angl. t. 13, f. 1, which is Crataegus cordata. Тһе specimen labeled 
Crataegus coccinea in the Linnaean Herbarium was from a plant 
cultivated in the Upsala Garden, and, being unable to determine any 
of Plukenet's specimens, it was this specimen that I formerly considered 
the type of Crataegus coccinea and referred to it a common species of the 
New England coast and the St. Lawrence Valley (see Bot. Gazette, 
xxxi. 11). Aiton's specimen of Crataegus coccinea in the British 
Museum is a barren shoot of some Molles species. 
Under Rule 51 of the Vienna code it is provided in Section 4 that 
every one should refuse to adopt a name “when the group which it 
designates embraces elements altogether incoherent or when it becomes 
a permanent source of confusion and error." ‘This is the case of 
Crataegus coccinea. Certainly the type of Crataegus coccinea cannot 
be determined and a large number of different species have at different 
times been called Crataegus coccinea. It appears therefore desirable 
to abandon the name entirely and to find a new name for the plant 
figured as Crataegus coccinea in The Silva of North America and in 
the Manual of North American Trees. A glabrous form of this which 
I have called Crataegus coccinea rotundifolia was first described in 
1785 by Moench (Bäume Weiss. 29, t. 1) as Crataegus rotundifolia, 
which would therefore be the name of the species if the hairy and the 
glabrous forms are considered to belong to one species; and the hairy 
plant which I have described as Crataegus coccinea may then become 
Crataegus rotundifolia var. pubera. 
ARNOLD ARBORETUM. 
