PAPERS OX BIOLOGY AND AGRICULTURE 



177 



during this period was somewhat less than during the 

 preceding interval. A noticeable feature is the number 

 of species which have come from the West. Several of 

 these have not yet spread far from the railroads, where 

 one would expect the conditions for acclimitization were 

 not the best. The writer is indebted to Dr. H. S. Pepoon, 

 of the Lake View High School, Chicago, for the follow- 

 ing list of plants coming in during this time. 



1S97-1921. 

 Sorghum halepense 

 Arena fatua 

 Bromus hordeaceus 

 Bromus inermis 

 Rumex elongatus 

 Atriplex argentea 

 Spergularia mariana 

 Stellaria aquatica 

 Lychnis coronaria 

 Gypsophila niuralis 

 Ranunculus acris 

 Chelidonium majus 

 Thlaspi arvense 

 Camelina microcarpa 

 Raphanus sativus 

 Brassica alba 

 Brassica juncea 

 Brassica Xapus 

 Brassica campestris 

 Diplotaxis muralis 

 Hesperis niatronalis 

 Barbarea vulgaris 

 Erysimum asperum 

 Polanisia trachysperma 

 Potentilla recta 

 Crotallaria sagittalis 

 Trifolium incarnatum 

 Trifolium agrarium 

 Kallstroemia maxima 



Euphorbia marginata 

 Euphoribia Peplus 

 Oenothera pallida 

 Oenothera speciosa 

 Oenothera serrulata 

 Cynanchum nigrum 

 Cuscuta Epilinum 

 Gilia linearis 

 Echium vulgare 

 Verbena bipinnatifida 

 Lamium maculatum 

 Lamium amplexicaule 

 Leonurus Marrubiastrum 

 Mentha rotundifolia 

 Solanum elaeagnifolium 

 Physalis Alkekengi 

 Physalis pumila 

 Physalis longifolia 

 Lycium halimifolium 

 Petunia violacea 

 Plantago aristata 

 Iva xanthifoiia 

 Lepachys columnaris 

 Coreopsis tinctoria 

 Artemisia kansana 

 Artemisia vulgaris 

 Artemisia procera 

 Geranium pusillum 

 Tribulus terrestris 

 Arctium minus 



An examination of the foregoing list reveals several 

 points of interest. Xearly one-third of the species are 

 introductions from the West. Barharea vulgaris, Aster 

 angustus and Spergularia mariana are cosmopolites. 

 The first is thought to be indigenous to the Xorthwest, 

 and to have spread eastward. The case of Spergularia 

 mariana is interesting. It is a plant of the Atlantic and 

 Pacific seaboards, and saline regions of the interior, ac- 

 cording to Gray's Manual. The tendency to spread east- 

 ward is rather striking in the two families Solanaceae 

 and Onagraceae. Plants evidently escaping from culti- 

 vation are Sorghum halepense, Bromus inermis, Lychnis 



