ECOLOGIC SUBTERRANEAN ANATOMY OF PLANTS 
lOI 
Asclepias verticillata, Monarda fistulosa, Aster azureus, Liatris squarrosa, 
Solidago canadensis, Heliopsis scabra, Helianthus tuberosus, Monarda fistu- 
losa, Artemisia ludoviciana. 
The terminal or absorbing roots of four plants were studied and others 
were examined. The structure of the four roots drawn is typical and may 
be summarized as having a deep cortex (in this case 4/5-5/6 the radial depth 
of the stem) of aerenchyma or loose parenchyma, only a trace of, or no, 
mechanical tissue, and a variable vascular tissue with reference to the size 
and number of tracheae. It is evident that the function of these roots is 
absorption only. There is usually a little mechanical tissue in the upland 
species and a little more specialization of the vascular tissue. 
Ranunculus multifidus has entirely a fibrous root and retains the primi- 
tive root character to maturity. It has no mechanical tissue. 
Of the root structures studied, six were of upland plants and one of an 
alluvial basin plant. (Most of the prominent alluvial basin plants have 
rootstocks). Here parenchyma, found only in the cortex, was compact, 
reduction in space being supplemented by the presence of cork, collenchyma, 
or mechanical tissue. Reduction or absence of mechanical tissue was 
Comparison of Tissues of the Subterranean Organs 
Roots 
Radial 
Mechanical 
Tissue 
Name 
Habitat 
Root 
Depth 
Cortex 
Parenchyma 
Vascular Tissue 
Typha 
Al. bas. 
Terminal 
4/5 
Aerenchyma 
None 
Fairly 
latifolia 
prominent 
Phragmites 
Al. bas. 
Terminal 
5/7 
Aerenchyma 
Trace 
Distinct; not 
communis 
prominent 
Iris 
Al. bas. 
Terminal 
5/6 
Aerenchyma 
Moderate 
Fairly 
versicolor 
prominent 
Vernonia 
Al. bas. 
Primary 
1/2 
Aerenchyma 
Moderate 
Limited ; 
fasciculata 
prominent ; 
parenchyma 
tracheae 
few 
Ranunculus 
Al. bas. 
Main 
4/5 
Aerenchyma 
None 
Limited 
delphinifolius 
fibrous 
Polygonum 
Al. bas. 
Primary 
1/4 
Spongy 
Moderate 
Tracheae 
muhlenbergii 
cork 
numerous 
Lepachys 
Upland 
Terminal 
1/2 
Fairly 
Slight 
Tracheae 
pinnata 
compact 
prominent 
Potentilla 
Upland 
Primary 
1/6 
Compact 
Prominent 
Tracheae 
arguta 
large, 
numerous 
Desmodium 
Upland 
Primary 
1/6 
Slight 
Prominent 
Tracheae 
illinoense 
cork 
in stele 
large, few 
Petalostemum 
Upland 
Primary 
1/6 
Thick- walled 
Prominent 
Tracheae 
candidum 
cork 
large, 
numerous 
Gentiana 
Upland 
Primary 
1/2 
Prominent 
Absent 
Tracheae 
Pjiherula 
few 
Solidago 
Upland 
Secondary 
1/2 
Parenchyma 
Prominent 
Tracheae 
canadensis 
thick-walled 
large 
Baptisia 
Al. bas. 
Primary 
1/2 
Prominent 
Moderate 
Tracheae 
leucantha 
few 
