36 
the rocks of several arroyos and I was very much surprised at the 
number of species that I encountered, as I had hardly expected 
any cacti would exist at this temperature or elevation. They 
are mostly low-growing forms, an exception being a columnar 
Cereus which I have seen to attain the height of five feet. At 
this time, the wet season, they were all very fleshy. The elliptic 
jointed opuntias which form semicircular masses sometimes 
sume, must made ing he dry winter months, when I 
Collection here proved very difficult; although the hotel man 
promised me a guide and horses several days in succession, they 
were never forthcoming, thus compelling me to work practically 
alone. The rarity of the atmosphere made it impossible for me 
'y 
than ordinary exertion or carrying more than a trifling load was 
impossible. 
search for help I entered the office of a German 
commercial establishment where the kind clerk soon informed 
me that their cashier, Mr. Heinrich Schroder, was an expert in 
cacti and I lost no time in meeting him. He had for years owned 
an amateur collection, as many of his countrymen of the Father- 
ccompan 
was highly appreciated, for he pointed out several species that 
I certainly would have overlooked. As I had met with such slow 
progress and was eager to get all I could out of this I remained 
afield until nearly dark of my last day’ s stay and it was not until 
after dawn. The trip to Tucuman required forty-eight hours of 
