THE PLANT WORLD 13 



It is quite possible that the Taro and the Tanier were the first plants 

 to be cultivated by man — which means that they have been aids to 

 civilization for at least 100 and perhaps for over 300 centuries. 



Mayagiiez, Porto Rico. O. W. BARRETT. 



THE SENSITIVE PLANT AS A WEED IN THE TROPICS. 



Every one who has travelled much in the tropics knows that Mimosa 

 pudica is a weed which gives considerable trouble to the planters, but so far 

 as I am aware no photographs of the way it luxuriates have been published. 

 It may be interesting to those who have not seen the plant in its own 

 home to look at a photographic reproduction of a large patch of it w^hich 

 I observed recently in Ceylon. 



I was returning from Peradeniya to Colombo and the train stopped 

 for a few minutes at a way-station in the lowlands, an hour's ride from 

 the city, just long enough, in fact, to allow me to get a snap shot of a 

 field quite disfigured by Mimosa. The cattle pastured in the field had 

 eaten the herbage closely around the plant, leaving it strictly alone, and 

 as it crept across the meadow it killed out all other plants, forming a 

 dense deep patch of spiny, creeping stems and delicate pink blossoms, 

 which resembled miniature dandelion or thistle heads gone to seed. 



The leaves were all expanded horizontally^ as I approached, but when 

 my feet shook the soft earth, like a hermit crab draws into its shell or a 

 coral pulls in its tentacles, the plants in the radius of the shaken ground 

 quickly folded their leaflets together and dropped their leaves into the 

 characteristic position of rest which every one knows who has .seen the 

 living plant. 



To one acquainted only with the delicate specimens in European and 

 American greenhouses, the novelty of walking over such beds of it in the 

 tropics does not soon wear ofif. I have been on railway lines whose 

 embankments were covered with Mimosa, and watched with keen amuse- 

 ment, as the train advanced, the quick falling of the leaves like the prog- 

 ress of a roller on the seacoast. 



In Ceylon the planters complain that it is among their most trouble- 

 some weeds, and one sees it everywdiere in the cocoanut groves and tea 

 plantations. Though highly interesting and valuable in a 1>otanical 

 laboratory, Mi?nosa pudica is quite useless on a tropical e.->tate. — David 

 G. Fairchild, in The Botanical Gazette. 



