Arizona 1 

 Exp. atsi.jf 



LIFE HISTORY OF THE KANGAEOO RAT. 



21 



Grams. 



190 



90 



50 



2 



Den 4. 



September 20. 191S. In Calliandra type. Stony or gravelly soil, red, nearly 

 denuded of grass. 



Species stored. 



Prosopis velutina . 



Mollugo verticillata (pure) 



Anisolotus trispermus (mixed, but mostly of this genus) 



Solanum elaeagnifolium (12 fruits) 



Per cent. 



Mollugo verticillata (inseparable) 50 



Bouteloua rothrockii '. 1 



Bouteloua aristidoides 10 



Lepidium lasiocarpum Tr. 



Polygala puberula Tr. 



Ayenia microphylla ,__ 2 



Portulaca suffrutescens 1 



Aplopappus gracilis - . Tr. 



Alternanthera repens- 1 



Tridens pulcliella , 1 



Plantago ignota 33 



Panicum hallii - Tr. 



Fleshy fungi (putfballs) 



400 



Total 



Fifteen species represented in addition to the fleshy fungi. No perceptible 

 grass growth from the summer rains here, therefore dependent on a wide variety 

 of scattering plants. 



Den 6. 



October IT, 191S. Mixed type, partially denuded, no growth from summer 

 rains. Sandy soil. 



Species stored. Grams. 



Bouteloua rothrockii (crowns) (heads 1 to 2 per cent) 1, 435 



Bouteloua rothrockii (heads and crowns, about 50 per cent of each) 325 



Bouteloua rothrockii (with small percentage of crowns) 315 



Boerhaavia wi-ightii (with a few grass crowns) 1.50 



Prosopis velutina 80 



Solanum elaeagnifolium (.3 fruits) Tr. 



Total 2, 315 



Four species represented. Count of 100 grams of stored Bouteloua crowns 

 gives 1,700, or 17 crowns per gram. At this rate there were at least 27,000 

 crowns stored in this burrow. If a density of 250 plants to the square yard be 

 iissumed (a high estimate) these crowns represent the total B. rothrockii on 104 

 square yards of range surface. Further examination of the vicinity of this den 

 showed that the surrounding area Avas not completely cleai'ed, but was devoid of 

 B. rothrockii, while still having B. eriopoda with crowns undisturbed. 



Den 11. 



April 9, 1919. In partially denuded land where good spring growth of 

 EsclischoUzia was in bloom at time of excavation. Stomach of spectabilis killed 



