620 



A VIGOROUS FOREIGNER. 



the surface of the ground, the smoke finally passing out 

 of the chimney. Near, and for some distance from the 

 furnace, build the flue of brick to prevent fire, but the 

 rest construct of boards. In summer the sash can be 

 removed, and in winter it would be better to apply a 

 mulch and cover the frame with boards rather than the 



sash, as it would be more apt to give an equal tempera- 

 ture. Arrange the beds on each side of the walk, and 

 plant as mentioned for the forcing house. It will be 

 necessary to manure heavily and often where so little 

 earth is given to each plant. This plan of growing will 

 give profitable results. F. E. Rupert. 



A VIGOROUS FOREIGNER. 



(prickly lettuce 



THE introduction and spread of prickly let- 

 tuce onAmerican soil furnishes an excellent 

 example of the ability of a well endowed 

 plant to over-run a new region and crowd 

 out the native forms, as well as immigrants of 

 longer standing. I do not know just when the 

 species was introduced. It is not in the 1866 

 edition of Grafs Manual of Botany ; but in Gray's 

 Synopfkal Flora, 1884, it is mentioned as becoming 

 common in the Atlantic states in gardens and 

 around dwellings. In the sixth edition of the 

 manual the plant is reported to occur in waste 

 places and along roadsides from the Atlantic states 

 to Missouri — a rapid spread in six years. But 

 probably in 1884 it had already entered many 

 other states away from the Atlantic coast. It cer- 

 tainly occurred in Ohio as early as 1879, having 

 been collected that year in Toledo and Painesville. 

 A few plants were found in the vicinity of Colum- 

 bus in 1882, and since then the species has spread 

 enormously. It now occupies a large portion of 

 the commons and waste fields about the city, having 

 crowded out nearly everything before it. There 

 are many fields of several acres each in different 

 parts of town, where the plants will average three 

 to the square foot. The same is true of many 



Laciuca scariola, L.) 



other cities of the state, and of too many towns 

 and villages. 



Prickly lettuce is a composite plant growing to a 

 height of two to six feet (probably averaging between 

 four and five), with narrow open panicles of small yel- 

 low flowers. The leaves are pale green, sagittate, and 

 have a row of stiff prickles on the under side along the 

 mid-rib. They are usually twisted into a more or less 

 vertical position. Few plants are better prepared for 

 survival. The stem is solid, and furnished with a 

 milky juice. Its solidity enables it to become erect 

 again when trodden upon, and combined with the 

 milky juice, protects it from insect borers. The 

 prickles on the stem and leaves are a protection from 

 herbivorous mammals. The seed is provided with a 

 fine pappus, so that it is easily carried long distances by 

 the wind. Each plant produces a large number of 

 seeds. One of my assistants, after a number of counts, 

 estimated that each plant produced, on an average, 688 

 heads, with an average of 12 seeds to the head, or 

 8,256 seeds to the plant. With three plants to the 

 square foot, this gives 3,234,453,120 seeds to the acre ! 

 No wonder it can over-run things ! 



The accompanying plate, from drawings by Miss 

 Freda Detmers, faithfully represents the plant. At a 

 is shown a branch with flowers ; at a section of the 

 lower portion of the stem ; at c, a single flower, and at 

 (/, a seed with pappus. Clarence M. Weed. 



Ev'n in the stifling bosom of the Town, 

 A Garden in which nothing thrives has charms 

 lhat soothe the rich possessor ; much consoled 

 That here and there some sprigs of mournful mint, 

 Of night-shade or valerian, grace the wall 

 He cultivates. 



— COWPER. 



