358 CARNEGIE INSTITUTION OF WASHINGTON. 



abundance of hay-fever species in and about Colorado Springs have been 

 recorded in detail, and it is proposed to map these as a further guide to 

 diagnosis. The distribution of pollen has been studied under varying con- 

 ditions and surroundings in different parts of the city, and improved methods 

 have been developed for collecting, sifting, and preserving pollen and preparing 

 pollen extracts. At the same time an energetic campaign has been waged to 

 secure the cutting of the weeds of vacant lots, streets, and alleys, with the 

 discovery that successive mowings are necessary to prevent regeneration suffi- 

 cient to prolong the period of flowering, although the total pollen production is 

 greatly decreased. 



A special endeavor has been made to render methods of diagnosis more 

 direct and accurate. In addition to the map of distribution and the chart of 

 seasonal production, a method of local diagnosis has been developed by means 

 of a survey of the immediate neighborhood of the patient and of the regular 

 use of pollen slides for catching the pollens concerned. With the aid of the 

 history of each case, this usually discloses the offending pollen at once, or 

 narrows the choice of extracts for the intradermal test to two or three at most. 

 With respect to the action of specific pollens, 7 species and varieties of 

 Artemisia, which comprise the sagebrushes and sageworts, and several related 

 genera of the ragweed and lamb's quarters groups, are being made the subject 

 of a special research. In Colorado the sageworts have been found to be much 

 more important than the ragweeds, Russian thistle and lamb's-quarters 

 have proved much more virulent than in the East, and a new plant, the sum- 

 mer cypress (Kochia scoparia), has been added to the list of important causa- 

 tive species. This is especially significant, as this species is widely planted in 

 gardens for hedges. 



BOTANY. 



Britton, N. L., and J. N. Rose, U. S. National Museum, Washington, D. C. 

 Studies of the Cactacece. (For previous reports see Year Books Nos. 

 11-16, 20.) 



The cactus project is being brought to a close. Our time during the past 

 year has been spent on volumes 3 and 4. Volume 3 was issued October 12, 

 1922, and consists of 255 pages, 24 plates, and 250 text-figures. Volumes 1 

 and 2, previously published, were issued June 21, 1919, and September 9, 1920, 

 respectively. The manuscript for volume 4 contains about 1,000 pages, 37 

 plates, and about 250 text-figures. 



Interest in the cactus family has greatly increased recently. In Europe 

 there is almost a cactus craze and dealers and cactus fanciers are anxious to 

 obtain seeds and plants. Some horticulturists are making a speciality of this 

 family and new additions of popular cactus works are being brought out. The 

 interest in Holland is very strong and a catalogue of all the cactus names, 

 based on this monograph, is being prepared there. The larger botanical insti- 

 tutions are building up their cactus display collections and at least one of our 

 American collectors has been engaged to ship cacti from all over Mexico 

 for the next two years. 



