BRIEFER ARTICLES 
NEW COLORADO SPECIES OF CRATAEGUS 
(WITH TWO FIGURES) 
During the past three years the writer, together with Messrs. G. S. 
Dopps and W. W. Rossrns, has been making ecological studies of mesa 
and gulch plants in the vicinity of Boulder, Colorado. In tracing out the 
distribution of Crataegus it became apparent that there were present 
some undescribed species. Full and complete collections were made 
therefore by Mr. Dopps and the writer during the present season from 
marked trees, in order that there could be no confusion in regard to the 
Specimens. Very complete notes of abundance, occurrence in different 
drainage areas, etc., were made. Fruits were preserved in alcohol as well 
as by drying. 
It was expected at the beginning of the study that the new forms would 
be found to be hybrids between previously described species. This, 
however, is not the case. The distribution of C. Doddsii, in particular, 
shows that it is a true species. Isolated thickets of C. Doddsit have been 
found as far as five or ten miles away from any trees of other species of 
Crataegus. Various other considerations which will be noted elsewhere 
lead to the belief that the Colorado species of Crataegus do not 
hybridize. 
A paper by my colleague, Professor T. D. A. COCKERELL," gives a 
full account of the species described for Colorado up to the present time. 
Tam much indebted to this paper and to suggestions from its author. 
The following species have the characters of TOMENTOSAE of SARGENT 
and should be placed in that group. The first might almost as well be 
Placed with CoccrnEae. e 
Crataegus Doddsii, sp. nov.—Arbor parva, vel frutex; ramis cineraciis, 
spinescentibus; ramulis junioribus glabris vel paululum pubescentibus, 
colore castaneato. Folia lucida; glabrata, sed nerviis infra pubescentibus ; 
obovata, saepe ad apicem truncata, margine serrata, et superne obscure 
lobata. Petiolus longe }-4 laminae; superne margine angusta glandulosa. 
Flores conspicui; corymbis compositis ; pedicellis glabris vel majus minusve 
pubescentibus; staminibus ro vel minus; antheris albis. Fructus durus, 
cum pilis raris, late pyriformis; longe 9™™, in longitudinem costatus; 
- * Univ. of Colorado Studies 5241-45. Dec. 1907- 
381] [Botanical Gazette, vol. 46 
