354 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



branched annual, inhabiting the sandy wastes of North Africa 

 and Syria. We may repeat here that when the individual 

 plant lias fulfilled its mission that is to say, produced flow- 

 ers and when the seed is in course of ripening, the leaves 

 decay and fall off, and the branches curve inward, forming a 

 ball of the entire plant. After this it soon becomes detached 

 from the soil, and is blown hither and thither with the mov- 

 ing sands. 



During this time the seed-vessels remain closed, but the 

 first rain causes the branches to unfold and the seed-pods to 

 open. Now it is obvious that the most favorable condition 

 for the continued reproduction of an annual plant in the 

 shifting sands of the desert must be quick germination and 

 growth and a kind of locomotion. The strange prickly, 

 almost or quite leafless shrubs and undershrubs characteristic 

 of the desert flora retain their vitality for years, alternately 

 buried beneath the sand and exposed to the influences of the 

 sun and air ; but an annual plant would probably soon become 

 extinct under the same conditions. According to a writer in 

 the Gartenflora^ seeds of the Aoiastatica Jderochuntina, sowed 

 about five o'clock in the afternoon, had germinated by one 

 o'clock the following day, and their rootlets had already 

 pierced the soil. These seeds were taken from a plant pur- 

 chased at the Vienna Exhibition, and twelve out of fifteen 

 germinated in the time mentioned in a pot covered over with 

 a saucer, and standing in an ordinary living-room. This, like 

 the germination of the seeds of the mangroves on the trees, 

 seems to be a special provision for the perpetuation of the 

 species. 18 A^ September 15, 1876, 11. 



A NEW NOXIOUS AVEED. 



Of late years, among other noxious weeds at the South, 

 one has appeared in great abundance, the hooked sides of 

 which attach themselves very rapidly to the legs of cattle, 

 and constitute a frightful nuisance, which, indeed, is spread- 

 ing, and threatening to make its way over the whole United 

 States before long. According to the Bulletin of the Torrey 

 Botanical Club, in 1851 a woolen-factory near Augusta, Geor- 

 gia, received a quantity of wool imported from Buenos Ay res. 

 This contained a great number of small burs, which were 

 separated by the picking-machine, and the " trash " thus re- 



