Scrophulariaceae and Orobanchaceae 175 



Explanation of Plates. 



Key to the lettering of Figures 1-16. 



r — The primary root from which are given off secondary rootlets. 



st — Stem. 



hr — Host root 



fl — Foliage leaf. 



fs — Foliage scale. 



i — Inflorescence axis. 



Plate XII. 



Fig. 1. Root system of Gerardia flava showing parasitic attachment. 

 (From a drawing by Mr. J. Stauffer in Gray's "Structural Botany.") 

 Fig. 2. Root system of Gerardia purpurea. Natural size. 

 Fig. 3. Root system of Gerardia aphylla. Natural size. 

 Fig. 4. Root system of Orobanche minor. 



Plate XIII. 



Fig. 5. Root system and part of stem of Orobanche minor attached to 



clover root. (After Koch). 

 Fig. 6. Stem and root system of Aphyllon uniflorum parasitic on the 



roots of Aster corymbosum. Natural size. 

 Fig. 7. Tuberous swelling consisting of stem and root system of Epi- 



phegus virginiana. Natural size. 

 Fig. 8. Stem and root system of Orobanche cruenta with constricted neck 



at the junction of stem and root. Natural size. 

 Fig. 14. Root, underground stem, and lower part of inflorescence axis 



of Lathraea japonica. (X }4). 

 Fig. 15. Orobanche minor. Note the short condensed stem, from i 



downward, as compared with that of Lathraea. (X }4). 

 Fig. 16. Aphyllon. Stem still more condensed and shorter than that 



of Orobanche. (X }4). 



Plate XIV — Note the gradual condensation and shortening of stem in Figs. 

 9-13. Foliage leaves become scales. 

 Fig. 9. Gerardia flava. (X Vi)- 

 Fig. 10. Gerardia aphylla. (X /€)• 

 Fig. 11. Gerardia aspera. (X X A). 

 Fig. 12. Harveya capensis. (X ]4)- 

 Fig. 13. Hyobanche. (X 14). 



Plate XV — Figures 17-27 show the downwardly-directed processes at the 

 base of the anther lobes. (X 10). 



Fig. 17. Stamen of Gerardia flava. 



Fig. 18. Stamen of Gerardia purpurea. 



Fig. 19. Stamen of Harveya coccinea. Note the elongated sterile an- 

 ther lobe. 



Fig. 20. Stamen of Bartsia. 



Fig. 21. Stamen of Melampyrum. 



