Hitchcock — Studies on Subterranean Organs. 3 



The parenchyma of the pith is abundantly stored with inulin, 

 while the outer part of the phloem is well supplied with an 

 oil which was not determined. There is no starch or tannin. 

 In another series the crown increases in length each year, 

 the inflorescence being axillary and the leaves forming a 

 rosette. In Troximon cuspidatum the crown is simple, while 

 in Tarox'icum officinale it is branched. In the latter and 

 probably the former the crown is drawn down into the ground 

 each year by the contraction of the root. 



In a third series no strong root is formed, the root system 

 consisting of fibers. At the base of the first stem, buds are 

 formed which produce shoots the succeeding year. This goes 

 on from year to year. The crown thus formed consists of a 

 mass of stems, the bases of old shoots. This is one of the 

 largest categories. In Aster sericeus the large white buds 

 that are to form next year's shoots can be seen closely ap- 

 pressed to the old stem. If the new shoots grow obliquely 

 or horizontally for a short distance before emerging from the 

 soil a matted crown is formed consisting of intertwining stem 

 bases, which might with equal propriety be called short rhi- 

 zomes. Vernonia Baldioinii forms such a crown. Thus we 

 find a gradual transition from the simple crown of Aster seri- 

 ceus to rhizome production. In some species the connection 

 between the old stems soon rots away and the crown is easil}^ 

 separated into its component parts. To the crown formers 

 of this third series belong: Vernonia Baldwinii, V. fascicu- 

 lata, Eujpatorium allissimum, E. perfoliatum, E .ageratoides, 

 .Solidago rigida, S. speciosa angustata, S. nemoralis, Aster 

 azureus, A. sericeus, A. Drummondii, A. laevis, Silphium 

 integrifoHum, Heliopsis scabra, Echinacea angustifoUa, Ac- 

 tinomeris squarrosa, Hymenopappus corymbosus, Chrysanthe- 

 mum Leucanthemum . 



Silphium laciniatum produces strong woody root-like rhi- 

 zomes. This needs to be investigated further, but it seems 

 that when a branch of the rhizome has produced a flowering 

 shoot it ceases to grow. But branches which produce a 

 rosette of leaves form a strong bud at the apex. This 

 bud appears partly buried in the substance of the rhizome. 

 How long these branches form rosettes before they finally 



