100 
ADA HAYDEN 
Habitat: Dry to moist slopes. 
Gross structure: Tuber-like rhizome; rather short; radial extension; bears clusters of 
small roots. 
Histology of rhizome (Plate XXV, fig. 2): 
Primary cortex: Depth 1/9 radius rhizome; hypodermal collenc'hyma; scattered 
sclerenchyma among the elongated parenchyma; endodermis walls of uniform 
thickness. 
Stele: Collateral bundles; xylem fascicles branched above the first annual ring; 
broad rows of rectangular-formed wood rays separating the bundles or branches 
thereof ; tracheae numerous; wood fibers prominent; primary endarch xylem 
distinct; pith parenchyma cells hexangular. 
Summary: Mechanical tissue prominent; structure of stem compact. 
Lepachys pinnata (Vent.) T. & G. 
Habitat: Slopes; moist to dry. 
Gross structure: Abbreviated rhizome; hard; clusters of slender roots. 
Histology of rhizome (Plate XXVHI, fig. i): 
Primary cortex: Depth 1/6 radius of rhizome; parenchyma with clusters of scle- 
renchyma; endodermis not distinct. 
Stele: Collateral bundles; xylem fascicles branched; separated radially and some- 
times transversely by wood rays of parenchyma ; tracheae few, small; wood paren- 
chyma prominent; pith parenchyma with clusters of sclerids scattered through 
it. 
Summary: Mechanical tissue abundant; tracheae small, few; parenchyma rays con- 
spicuous. 
Histology of root : 
Primary cortex: Depth 1/2 radius root; parenchyma with sclerenchyma cells 
scattered through; endodermis not distinct. 
Stele: Tracheae prominent; wood fibers abundant. 
vSummary: Mechanical tissue prominent; cortex deep. 
Helianthus tuherosus L. 
Habitat: Moist slopes. 
Gross structure: Slender, radially extensive rhizomes; tuberous. 
Histology of rhizome (Plate XXVH, fig. 3): 
Primary cortex: Depth 1/4 radius of root; hypodermis of collenchyma; paren- 
chyma large-celled, loose; resin glands scattered through parenchyma; endoder- 
mis not distinct. 
Stele: Collateral bundles; phloem tipped with patches of sclerenchyma; tracheae 
few; woody parenchyma sparse, rather thick- walled ; pith parenchyma of large, 
round cells, loose; resin glands scattered among pith. 
Summary: Parenchyma prominent; mechanical tissue sparse. 
Analysis of the Anatomy of Subterranean Organs 
Of the twenty-six subterranean organs studied, fiften were upland 
plants and eleven were plants of the alluvial basin. 
Alluvial basin species: Typha latijolia, Phragmites communis, Spartina 
Michauxii, Panicum virgatum, Scirpus fluviatilis, S. validus, Iris versicolor, 
Polygonum Muhlenbergii, Ranunculus delphinifolius, Vernonia fasciculata, 
Asclepias verticillata. 
Upland species: Heuchera americana, Potentilla arguta, Petalostemum 
candidum, Baptisia leucantha, Desmodium illinoense, Gentiana puherula, 
