ANNUAL REPORT, 1945-46 53 



groups were fed the same diet devoid of calcium, one being kept at 62° and the 

 other at 87°. These animals were allowed to eat as much of the calcium-free 

 food as they wished, but all were given an identical quantity of calcium separate 

 from the ration. In all three series the animals were of the same age and were 

 fed arid cared for in the same way. 



In Series 1, the quantity' of ash stored by the animals was dependent on the 

 quantity of food eaten; those eating the smaller amount of food had the smaller 

 amount of ash in their bones, whereas those eating more food had the greater 

 amount of ash. In contrast, the rats in Series 2 stored almost identical quanti- 

 ties of ash in their bones, irrespective of the quantity of food eaten. In Series 3, 

 the rats reared at 62°F. had no more ash in their bones than did their litter-mates 

 reared at 87°. 



These results show the importance of controlling the intake of calcium in studies 

 which are concerned with the growth and calcification of the skeleton. 



DEPARTMENT OF HORTICULTURE 

 R. A. Van Meter in Charge 



Study of Herbaceous Perennial Material. (C. J. Gilgut, Waltham.) The 

 perennii 1 test garden with its extensive collection of labeled plants is the only 

 one of its kind in New England. It is of value to nurserymen, landscape archi- 

 tects, students, and the gardening public, who wish to observe and study the 

 response of various plants to our local climatic conditions. At present, it con- 

 tains about 2500 plants, many of which are old garden favorites. There are 

 also many new varieties, recently introduced into the trade, and some placed 

 here by a number of hybridists, for comment and report as to garden value, 

 cultural requirements, and winter hardiness. 



Probably more new varieties of the so-called hardy chrj^santhemum are being 

 developed and introduced today than of any other garden flower. The collec- 

 tion here includes many, but not all, of the better introductions of the Korean 

 hybrids from Bristol Nurseries, and the hybrids from the University of Minnesota, 

 University of Chicago, University of New Hampshire, Colprit Nurseries, and the 

 United States Department of Agriculture. Although these chrysanthemums 

 are considered hardy, they have not been found reliably so in the test garden and 

 it has been found necessary to resort to wintering them in cold frames to insure 

 against loss by winterkilling. 



The extensive collection of tall bearded iris suffered conslderabh' from winter 

 injury, which was followed by much soft rot of the older rhizomes, in spite of a 

 mild winter and a good blanket of snow. There was more loss In the recently 

 transplanted iris than In those established for a year or more. Mulching the first 

 winter after transplanting might have prevented much of this loss. 



Factors Influencing the Rapidity of Growth of Nursery Stock. (C. J. Gilgut, 

 Waltham.) In a propagating medium of sand-peat in which a previous batch 

 of cuttings had rotted badly, several materials commonly recommended for 

 sterilizing media were tried. The dry chemicals were scattered over the sand-peat, 

 and the formaldehyde sprinkled on with a watering pot. Each was then thor- 

 oughly worked into the medium and cuttings of Taxus media Jiatfeldi were in- 

 serted. The materials used and the effect on rooting of cuttings are shown below. 



