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New cholla growth

The green spikes behind the new spines are rubbery. They are not present on older growth. I wonder what their purpose is. A Finger-leaved Gourd up at the north end, with a flower and a gourd on it. The White-thorn Acacias a showing some flowers, bright yellow puffballs, quite different from the creamy catkins of the Catclaw Acacia.

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About Bill McCallum

I was born in Australia and came to the United States to pursue a Ph. D. in mathematics at Harvard University, met my wife, and never went back. I am a professor at the University of Arizona, working in number theory and mathematics education.


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