PIONEER PLANTS ON A NEW LEVEE 



421 



crimiiiately, with many bare patclies of g^round in between. 

 Only in a few places were there any foci of poiSsible new for- 

 mations, these mostly g'rasses. In one such spot Panicum, Scrih- 

 neriamim was the dominant, in another, Panicum dichatomi- 

 floriun, in a third, Ambrosia art emdsae folia. An occasional 

 thornapple, Datura stramonium, made itself conspicuous. 



Thus in downfall and crumbling- ruin ends the age of the 

 weeds. They were given a little .comer of the earth to possess, 

 and they failed to hold it, even for themselves. Men will build 

 a new embankment, and will cover it with grass or some other 

 serviceable plant. It would seem that in any place such as 

 this, where a tenacious root is required as well as a braggart 

 top, organisms dedicated to the survival-struggle as frankly as 

 are the actors in the little drama we have been watching, are 

 after all not fitted to survive. 



Following is a list of species noted during the season of 1917. 

 Those marked with an asterisk are species which were noted 

 curing the first season and which have survived throughout. 



Zea mais 



Panicum Scribnerianum 

 Panicum cap ill are 

 Panicum dichotomifloirum 

 Echinochloa crus-galli 

 Setaria glauca* 

 Muhlenbergia mexicana 

 Avena sativa 

 Poa pratensis* 

 Carex sp.* 

 Salix sp.* 

 Populus deltoides* 

 Caiuiabis sativa* 

 Humulus Lupulus 

 Rumex crispus* 

 Polygonum pennsylvanicum* 

 Chenopodium album* 

 Salsola tenui'folia , 



Amaranth us, retroflexus* 

 Amaranthus blitoides* 

 Stellaris media* 

 Lepidium virginicum* 

 Brassica nigra* 

 Brassica oleracea 

 Trifolium pratense* 



Camp Dodje, Iowa. 



Trifolium repens 

 Trifolium hyOridum 

 Melilotus alba* 

 Phaseolus sp. 

 Vitis vulpinus* 

 Abutilon theophrasti* 

 Ipomoea purpurea* 

 Convolvulus arvensis* 

 Verbena stricta* 

 Lycopersicum eseulentum 

 D atu ra s t r a m o n i um * 

 Plantago major* 

 CitruUus vulgaris 

 Solidago scroti na* 

 Aster salicifolius* 

 Erigeron canadensis 

 Ambrosia trifida* 

 Ambrosia artemisa?folia* 

 Xanthium commune* 

 Helianthus annuus* 

 llelianthus tuberosus* 

 Bidens sp. 

 Arctium minus* 

 Lactuca scariola. 



