Papers in the Biological Sciences


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Bulletin of the Torrey Botanical Club (October 1904) 31(10).


Last December two fine twigs and a cluster of the ripe fruits of the "burro thorn" (Holacantha emoryi Gray) were brought to the Botanical Department of the University of Nebraska by Mrs. Dorothy Bacon, who had collected them in the Salt River valley, near Phoenix, Arizona. They at once attracted attention because of their complete leaflessness, and the thorny nature of their branches. The shrub is said to grow about three meters high, and to form ail impenetrable thicket from the ground up. It grows in the desert, where it was first found about fifty years ago by Major W. H. Emory of the United States Army in one of his expeditions. In the Notes of a Military Reconnaissance from Fort Leavenworth in Missouri, to San Diego in California (Washington, 1848), a poor drawing of a branch is given on the second plate of Appendix number 2 (page 157). From an imperfect drawing, probably the original of the one given in the plate, Dr. George Engelmann surmised that it might be some species of Koeberlinia, a excellent guess, as was afterwards shown.

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