Cook: Olneya Beans 



325 



beans are regular in shape, but some 

 trees have relatively shorter pods, so 

 that the beans are crowded and flat- 

 tened at one or both ends, and hence 

 irregular in size and form, which would 

 increase the difficulty of mechanical 

 cleaning and sorting (Fig. 16). Some 

 trees have relatively indehiscent pods 

 that fall to the ground without shatter- 

 ing, while on other trees most of the 

 pods open before falling, so that the 

 individual beans have to be picked up, 

 which takes much more time and labor. 



Color also appeared as a practical 

 consideration in collecting the beans, 

 for those that were light-colored, grayish 

 or brownish, were more difficult to find 

 than the dark purple beans of other 

 trees. The most difficult beans to 

 pick up from the ground were light 

 brown and finely speckled, these being 

 hard to detect among the litter of 

 coarse sand or gravel, fragments of 

 dead wood, dry leaves, and pods under 

 the trees. The colors range from a 

 uniform light tan through various 

 degrees of shading, mottling, and speck- 

 ling with dull or pinkish purple to 

 nearly uniform deep purple, nearly 

 black in the mass. 



From the standpoint of general de- 

 sirability and ease of handling it 

 seemed that the best trees to select 

 would be those that bore abundant 

 crops of long, many-seeded pods, not 

 opening too readily, with large, plump, 

 regularly formed beans, of the dark 

 purple color. One such tree was found 

 that seemed definitely superior to any 

 other in combining the several require- 

 ments. Photographs of this tree were 

 made, as well as of the pods and beans, 

 and a part of the seed was planted at 

 Sacaton, as Olneya No. 1 (see Figs. 

 13 and 17, No. 4). This tree had pods of 

 the largest dimensions, as- given above, 

 with beans attaining 11 mm. in length, 

 9 mm. in breadth, and nearly 8 mm. in 

 thickness. The surface of the beans is 

 smooth and even, but under a lens 

 shows very minute, close-set puncta- 

 tions. The hilum is white and rather 

 prominent, and there is a small oval pit 

 above the hilum, usually white and 

 flat at the bottom, '.hut sometimes 



reduced to a short, narrow groove. 

 On the other side of the seed, diagonally 

 across from the hilum, is a rather in- 

 distinct, broadly rounded prominence. 



Still larger beans, with measurements 

 of 12 mm. by 9.2 mm. by 7.2 mm., were 

 obtained from another tree. These 

 were of a nearly uniform light tan 

 color, very finely speckled with purplish, 

 and with much larger and less numerous 

 punctations. Beans from several trees 

 were weighed carefully by Mr. Harold 

 F. Loomis. Averages of ten weighings 

 of 50 seeds from samples representing 

 seven individual trees were 13.617, 

 14.808, 14.231, 7.895, 12.682, 14.431, 

 and 10.252 grams. The corresponding 

 average weights of single beans of the 

 seven trees are 0.272, 0.296, 0.285, 

 0.158, 0.254, 0.289, and 0.205 grams. 

 The largest bean weighed 0.395 gram, 

 with 0.357 gram as the average of 25 

 of the largest beans from the same 

 tree, and 0.302 gram as the average of 

 the sample from this tree, or nearly 

 twice the average for the tree with the 

 smallest beans. The largest beans are 

 shown in Fig. 15, the smallest in Fig. 17, 

 No. 2 and those of the tree considered 

 most desirable in Fig. 17, No. 4. The 

 tree with the largest beans bore only a 

 small and late crop and had short pods, 

 mostly with only one or two seeds, though 

 a few had three or four (see Fig. 15). 



The tree selected to furnish seed for 

 planting was near the Pima village of 

 Santan, north of the Gila River, op- 

 posite Sacaton. Two quarts of beans 

 were collected from this tree. These 

 were only a small part of the crop, but 

 the others could not be gathered be- 

 cause of heavy rains that made the 

 river impassable. 



In the deserts around Sacaton only a 

 few of the trees are large, most of them 

 being sprouts from old stumps. Even 

 the second growth is cut down as soon 

 as a thickness of a few inches has been 

 attained, although the yellow sap wood 

 of the new growth is rather soft and is 

 consumed rapidly by boring beetles. 

 Cutting the older trees reduces the seed 

 supply, and the second growth is 

 browsed by cattle until the foliage is 

 beyond reach. Browsing is worse, of 



