8 Trans, Acad. JSci. of St. Louis. 



Dysodia chrysanthemoides, Lag. Annual. Dry open 

 ground. 



Achillea Millefolium, L. Khizomes forming plants the same 

 year. Ehizomes short, sometimes mere offsets. Prairie. 



Chrysanthemum Leucanthemum, L. Crown compact. 

 Meadows and pastures. 



Artemisia dracunculoides, Pursh. A large woody branched 

 crown. Moist sandy soil. 



A. Ludoviciana, Nutt. Slender rhizomes. Prairie. 



Erechtites hieracifolia, Kaf . Annual. Moist open woods 

 and waste places. 



Arctium Lappa, L. Biennial. Waste places. 



Cnicus undulatus. Gray. Buds from creeping roots or 

 from the tuberous roots. Prairie. 



C. altissimus, Willd. Biennial, forming the first year a 

 fleshy root or lateral tuberous roots. Open woods and fence 

 rows. 



Lygodesmia juncea, Don. Buds on creeping roots. 

 Prairie or clay banks. 



Troximon cuspidatum, Pursh. A vertical caudex, usually 

 simple. Prairie or stony hills. 



Taraxacum officinale, Weber. Vertical tap-root supporting 

 one or more caudices. Root forms buds when cut. Waste 

 places. 



Lactuca Canadensis, Li. Biennial. Low ground, borders 

 of woods and waste places. 



L. Ludoviciana, DC, Biennial. Prairie. 



L. Floridana, Gaertn. Biennial. Woods. 



8onchus asper, Vill. Annual. Waste places. 



EXPLANATION OF ILLUSTRATIONS. 



Plate I. 



Liatris punctata. 1, 2, 3, Roots taken at successive stages of growth, 

 natural size. 4, Cross-section through phloem and part of xylem, showing 

 sclerenchyma strands and cambium. 5, Cross-section through old root, 

 showing annual rings in xylem. 6, Cross-section of sclerenchyma strand, 

 showing ducts. 7, Four sclerenchyma fibers. 8, Three fibers in cross- 

 section. 



Issued February 18, 1899. 



