194 TREE ANCESTORS 



are what are knowTi as compound, that is they consist of many- 

 separate leaflets. There are, in the locust, from 7 to 9 opposite 

 pairs of elliptical slightly stalked leaflets and an odd one at the end 

 terminates the slender stalk of the leaf, which is from 8 to 14 inches 

 in length. At the base of the leaf-stalk a pair of short subulate 

 stipules or accessory leaflets soon become transformed into straight 

 or shghtly recurved spines which persist for many years, often 

 becoming an inch or more in length. 



The flower clusters, which appear after the leaves toward the 

 end of May, convert the tree into a creamy white bower of incense, 

 since they are filled with fragrant nectar. The fruit, which ripens 

 late in the autumn, is a red-browTi pod, 3 to 4 inches long and ^ 

 an inch wide with 4 to 8 smooth brown seeds, which are shed from 

 the opened pods during the winter or early spring before the pods 

 let go their hold on the parent tree. The locust is one of our most 

 prolific trees in sending out sprouts from the roots, hence a tree 

 will spread rapidly and is difficult to eradicate. It grows rapidly 

 when young and thrives in the fertile soils of the Appalachian 

 Mountain valleys, but will also make a good growth on sandy or 

 rocky soils. 



The wood is heavy, exceedingly hard and strong, and very 

 durable in contact with ground or air, hence it is highly valued 

 for fence posts and rails, cross arms and insulator pins for telephone 



Pig. 42. Some Fossil Locusts and Coffee Beans (About f Natural Size) 



1, 2, 3. Leaflets and pod of the existing Rohinia pseudacacia Linn. 



4. Robinia hesperidum linger from the upper Miocene of Croatia. 



5. A probable locust leaflet from the Upper Cretaceous of South Carolina. 



6. 7, 8. Leaf and pods of Rohinia rcgeli Heer from the upper Miocene of 

 Baden. 



9. Another locust pod from the upper Miocene of Baden. 



10. A leaflet of the existing Gymnocladus dioecus Koch. 



IL Gymnocladus casei Berry from the Miocene of Oklahoma. 



12. A leaflet of a IMiocene honey locust, Gleditsia allemannica Heer, from 

 Baden. 



13. A leaflet of the existing honey locust. 



14. 15, 16. A thorn, leaf and pod of a honey locust, Gleditsia Wesseli Weber 

 from the lower Miocene of Germany. 



