UNIVERSITY OF COLORADO STUDIES 
characters for the separation of some of the species in the nutlets, par- 
ticulars of which will be given in Dr. Britton’s forthcoming work on trees. 
6. C. chrysocarpa Ashe. 
The Colorado species are as follows: 
. C. rivularis Nuttall=wheeleri Rydberg, Flora of Colorado (not of Nelson). Mr. 
Eggleston tells me that Rydberg was misled by receiving this from Wheeler as wheeleri. 
. C. saligna Greene. Syn. wheeleri A. Nels., fide Eggleston. 
. C. erythropoda Ashe. Syn. cerronis A. Nels. I had made this synonymy out from 
the descriptions, and Eggleston agrees.t It is a species with the leaves conspicuously 
shiny above. 
. C. colorado Ashe. I believed coloradensis A. Nels. to be the same, but it has smooth 
twigs, and must go rather with the next species. 
. C. occidentalis Britton. Mr. Eggleston agrees that my occidentalis is correctly named 
but says that the occidentalis of Rydberg’s Flora of Colorado was primarily based 
(as to the characters) on the Nebraska plant; which although cited by Britton as 
occidentalis, is really a different species. 
I have not recognized this. 
Mr. Eggleston, working from herbarium material had united occi- 
dentalis with colorado and coloradensis. 
There are, however, two quite 
distinct species, growing mixed together at Boulder. There is no ques- 
tion about the identity of colorado; but it is just possible that I have not 
correctly determined occidentalis, the latter having been based on a flow- 
ering specimen affording very few diagnostic characters—the color of 
the anthers being lost, and the leaves of the two plants being indistinguish- 
able. 
The following comparative table is derived from a couple of trees, 
standing a few feet apart, which have been examined at intervals for two 
years. 
C. colorado 
Anthers cream-color 
stigmas). 
Bark rougher (perhaps not a constant 
character). 
Young twigs thinly but evidently lanulose. 
Flowers earlier. 
In August with much more fruit; this 
brighter red. 
On October 2, foliage dark green. 
(10 stamens, 2-3 
C. occidentalis 
Anthers pink. 
Bark smoother. 
Young twigs strictly glabrous. 
Flowers later. 
On October 2, foliage becoming bright 
reddish-orange. 
The following fossil species of Crataegus have been found in Colorado: 
7. C. lesquereuxi Ckll. 1906 (acerifolia Lx., not Moench). Miocene; Florissant. 
x Nevertheless, there is a discrepancy in the color of the fruit, not yet explained. 
