416 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1930 



The experience of the authors, resulting from frequent examina- 

 tions of this plant from April 1, 1928, to July 31, 1929, as it grows 

 in the sand dunes of Imperial County, Calif., indicates that the 

 Ammobroma of that locality dries up during the dry seasons; in fact, 

 but two single specimens were found in the spring of 1929 and both 

 of these were attached to Eriogonutn deserticolv/m Wats., a much 

 larger and more drought -resistant shrub than either of the Coldenias, 

 which to Ammobroma appear preferable as host plants. 



During the dry season (ISIarch to June, 1929) we traced many dry 

 stalks of the Ammobroma of the previous season down through the 

 sand to the contact with the root of the host plant and in only two 

 cases did we find any life in the Ammobroma and then only a very 

 little within 1 or 2 inches of the point of contact. However, the 

 difference in our experience and that of Gray and Lumholtz may be 

 due to the fact that the Ammobroma of the Pinacate region of 

 Sonora has a different host plant which may be better able to support 

 Ammobroma through the dry seasons, or there may be more moisture 

 in the sand where they found it. 



During the 1928-29 season the most common host plants for the 

 Ammobroma of the Imperial County, Calif., sand dunes, the tw^o 

 species of Coldenia herein mentioned, made little if any growth; in 

 fact, the tops of most of them appeared to be practically dead. 



We have procured seed of the Ammobroma and scattered it near 

 the Coldenia of the sand dunes in Riverside County (Coachella 

 Valley), but so far no germinations have been noted. 



LITERATURE CITED 



1. Brandegee, T. S. Vegetation of the Colorado Desert in Zoe 5, p. 154, No. 9, 



May, 1903. 



2. Gray, Col. Andrkw B. Original ]*eport in letter addressed to Dr. John 



Torrey, dated at New York, October 20, 1S.j4, on Ammobroma sonorae. 

 Proceedings of the American Association for the Advancement of Science, 

 9th meeting, held at Providence, R. I., in August, 1S55, pp. 233 to 236. 



3. Jepson, W. L. a Manual of the Flowering Plants of California, p. 735, 



April 14, 1925. 



4. Johnston, Ivan M. Proceedings of the California Academy of Science, (4) 



12. 1143. N. 30. May 31, 1924. 



5. Palmer, Dr. Edwabd. Contributions from the United States National 



Herbarium, vol. 1, No. 1, p. 27, June 30, 1S90. 



6. Vassey, George and Rose, J. N. List of Plants Collected by Dr. Edward 



Palmer in 1890 at Head of the Gulf of California. Contributions from 

 the United States National Herbarium, vol. 1, No. 1, p. 27, June 30, 1890. 



7. SoLMS-LAUBACH, CouNT HERMANN. Die Familie dcr Lennoaceen in Abhand- 



lungen der Naturforschenden Gesellschaft zu Halle 11, pp. 119 to 178, pis. 

 1 to 3. (Heft 2, 1870.) 



8. ToRREY, Dr. John. Original description of Ammobroma. Annals of the 



Lyceum of Natural History of New York, vol. S, pp. 51 to 56, June 27. 

 1864. 



9. Lumholtz, Carl. New Trails in Mexico, pp. 318, 319, 330 and 331. 



