A RARE PARASITIC FOOD PLANT OF THE SOUTHWEST 



By FUANK A. TUACKEUV 



Senior Ayricultui i.st. United i^latcs Dcijartinetit of Ayficulture 



and 



M. Frencu Oilman 

 Collaborator, United Stittes Deijurtmcnt of Ayrieulture 



[With plates] 



The rare and interesting plant Ammohroma sonorae Torr. is found 

 only in the sand dunes of the southwestern United States and north- 

 ern Sonora and Lower California. Mexico, where the rainfall 

 averai;:es only about 2 to 5 inches per annum and where there are 

 sometimes periods as long as three years with practically no rain. 



Apparently, when plenty of moisture is made available by winter 

 or spring rains the plant grows very rapidly and is able, by stealing 

 from its host and by means or its own roots, to store suflicient moisture 

 in its long, fleshy, succulent stalk to mature and reproduce seed in 

 its chosen home in the sand dunes. In dry seasons this parasite is 

 extremely rare in the sand dunes of Imperial County, Calif., but if 

 the winter months have plenty of rain it is likely to be plentiful 

 there during the months of March, April, May, and June. The 

 larger and better specimens were collected by us in late May and 

 early June following a wet winter season. 



Just how this parasitic plant nudces its contact with the host root, 

 usually from 2 to 5 feet below the surface, forms a most interesting 

 subject which we are now attempting to solve. 



The word Ammobroma is derived from two Greek words, amnio 

 (sand), Iji'omos (food). The Papago Indians, who have used this 

 plant for foofl from time immemorial, call it biatatk {hki — sand or 

 sand hills — and tatk — root). 



It is a root parasite and belongs to the family Lennoaccae which 

 is usually ])laced next to the Hricacear, or Heath family. There are 

 only two genera of this family represented in the United States, 

 PJiolisina and Avwwhroma^ and only one species in each genus, 

 PJtolisma aren'iuin Nutt., and Aianiohroma sonorac Torr. In appear- 

 ance, Pholisma and Ammobroma are quite dilferent, the former 



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