i82 The Ohio Naturalist. [Vol. VII, No. 8, 



Martynia louisiana Mill. Phegopterishexagonoptera(Michx.) 

 Ruellia strepens L. Fee. 



strepens micrantha (En- Tofieldia glutinosa (Michx.) Pers. 



gelm & Gray) Britt. Cypripedium acaule Ait. 

 " ciliosa Pursh. " reginae Walt. 



Triosteum perfoliatvim L. " caudidum Willd. 



angustifolium L. " hirsutum Mill. 



Gnaphalium decurrens Ives. Cypripedium parviflorum Salisb. 



Anthemis cotula L. Peramium pubescens (Willd.) 

 Woodsia obtusa (Spreng.) Torr. MacM. 



Dennstaedtia punctilobula (Michx.) 



Moore. ^ 



Explanation of Plate XIII. 



Fig. 1. Cross section of leaf of Xanthoxylum americanum Mill, 

 showing position and character of a normal internal gland. 



Fig. 2. Cross section of leaf of Xanthoxylum americanum showing 

 an unusually large gland. 



Fig. 3. Longitudinal section of gland of Xanthoxylum americanum. 



Fig. 4. Cross section of leaf of Boebera papposa (Vent.) Rydb., show- 

 ing internal gland. 



Fig. 5. Cross section of leaf of Hypericum prolificum L., showing 

 position and character of internal gland. 



Fig. 6. Longitudinal section of gland of Hypericum prolificum. 



Fig. 7. Section of leaf of Glecpma hederacea L. showing external 

 scale. 



Fig. 8. Cross section of leaf of Gaylussacia resinosa (Ait.) T. and G., 

 showing position and character of an external secreting scale. 



Fig. 9. Section of scale of Gaylussacia resinosa, showing central 

 stalk cell. 



Fig. 10. Glandular hair of Urtica dioica L. 

 - Fig. 11. Glandular hair of .Cypripedium reginae Walt. 



Fig. 12. Glandular hairs of Corylus americana Walt. 



