Robinia 1501 



4. Robinia coloradensis, Dode, in Bull. Soc. Bot. France, lv. 650 (1908). 



A peculiar tree ' raised at Les Barres from seed, sent by M. Berthoud from 

 Golden in Colorado. It is probably a seedling of R. Holdtii. 



5. Robinia Holdtii britzensis, Spath, in Gartenflora, Hi. 557 (1903). 



This is a vigorous plant which was raised in Spath's nursery from a seed pro- 

 duced by a tree of R. neomexicana in 1893. It, however, closely resembles R. 

 Pseudacacia, only differing from this species in having traces of purple on the standard 

 of the flower. 



Distribution 



R. Pseudacacia is considered by American botanists to be indigenous in the 

 Alleghany Mountains from Pennsylvania to Georgia, but it is now widely naturalised 

 throughout most of the United States east of the Rocky Mountains and in Nova 

 Scotia and Ontario. Dame and Brooks say 2 that it is thoroughly at home in Maine, 

 forming wooded banks along streams, and fairly abundant in thickets and along 

 roadsides and fences in the New England States generally. Plate 353, reproduced 

 from a photograph sent by Miss Cummings, shows a tree at Boston (Mass.). A shrubby 

 form, which occurs in Kansas, Arkansas, and Indian Territory, is perhaps a true 

 native and not an escape from cultivation. The tree attains its largest size 3 in West 

 Virginia. It is found in the forest in mixture with other trees, growing on the slopes 

 with oaks, chestnut, hickories, and maples, while along the streams it is associated 

 with ash and black walnut. It often spreads by its root-suckers, forming thickets of 

 small trees. In the mountains of Pennsylvania and West Virginia, burnt and cut- 

 over forest lands are speedily covered with seedlings, 4 which often grow up into pure 

 stands of considerable extent. 



On account of the excellence of its timber for fence posts and for all uses 

 requiring contact with the soil, and also for fuel, the Robinia was much planted 5 

 formerly throughout the United States, and succeeded well south of the 38th parallel; 

 but at the present time planting is restricted or rendered useless on account of the 

 ravages of the locust-borer 6 (Cyllene Robinice, Forster). The grubs of this beetle 

 bore holes through the bark deep into the wood, which becomes completely honey- 

 combed with galleries. Young plantations are often attacked, especially in the States 

 east of the Rocky Mountains. The Robinia thrives in the dry prairie regions, and 

 has been planted with success on alkaline soil in the San Joaquin valley in 

 California. 7 



Introduction 



This species was introduced into France by Jean Robin, who received seeds 

 from America in 1601 ; and the oldest tree known was planted in 1636 by Vespasian 



1 Cf. Vilmorin, Frut. Vilmor. 54, fig. (1994), whose description does not agree with that of Dode. The individuals 

 that were raised may have differed considerably. i Trees of New England, 1 31 (1902). 



3 Ridgway measured a cultivated tree in Illinois, 95 ft. high and 11J ft. in girth. 



4 The seed is retained in the pods on the trees till late in the year, and is distributed to great distances by the strong 

 winter winds. 



6 Directions for planting in the United States are given in the United States Forest Circular, No. 64 (1907). 

 8 Cf. United States Entom. Comm., Fifth Keporl, 355 (1890). 7 Hilyard, Soils, 480 (1906). 



