39 



But to the botanist engaged in an\- kind of lield work (his for- 

 eign immigrant is a most undesirable accession to our plant po])- 

 ulation. It infests his fa\-orite hunting grounds and besets his 

 steps with a tanglefoot of snares even more exasperating than 

 the barbed wire fences, sometimes forcing him — and more espe- 

 cially her — to cut short such explorations. But the chief indict- 

 ment against it is the ruthlessness with which it is overrunning 

 and destroying our native plants wherever it comes in competi- 

 tion with them; and it is no uncommon thing to see acres upcMl 

 acres of brushwood and haw thickets, sometimes including trees 

 of considerable size, buried under the rank growth of this ag- 

 gressive invader. As it has no way of climbing except by coiling 

 around a support, which is a rather tedious process in the case 

 of large stems; it can reach the crown of high-branching trees 

 only by climbing upon the under brush of shrubs and young 

 shoots until it comes in contact with some overhanging bough — 

 and then it has a free right-of-way. It also utilizes the stems and 

 branches of other climbers that have already made good their 

 ascent — trumpet vine, catbriars, grape, Virginia creeper, and the 

 like, not excepting those of its own kind. As the stems of both 

 the twiner and its support grow larger, the tension often becomes 

 so great that the coils are tightened like a noose, and become so 

 deeply imbedded in the supporting stem as to give it the appear- 

 ance of a huge corkscrew^ and unless themselves broken or loos- 

 ened by the strain, may cause the death of the parts above. 

 More frequently however, it kills by smothering its victims under 

 a dense network of interlacing cords, commonly from 3 to 6 mm. 

 thick, loosely twisted together. I have counted as many as 27 

 strands of all sizes, from i to 10 mm. thick, twined into one of 

 these living ropes. A single stem is rarely more than i or 2 cm. 

 (about ^ of an inch) thick, though in one instance I have seen 

 a single honeysuckle vine 18 cm. (7 in.) in girth, smothering a 

 wild plum tree (P. nigra) 1.5 dm. (6 in.) in diameter. It began 

 by gripping a shoot from the base of the plum, in a spiral of 4 

 rings which have been drawn so tight by the continued growth 

 of both stems that the honeysuckle, the more elastic of the two, 

 has been flattened out like a piece of tape. As for the plum 



