Scrophulariaceae and Orobanchaceae 173 



of root and vegetative axis has resulted in practical obliteration 

 of any distinction of parts. 



5. The inflorescence axis from being greatly elongated to 

 constitute a several- to many-flowered raceme becomes a rela- 

 tively simplified axis with a reduced number of flowers, the cli- 

 max of which is reached in Conopholis, which bears a spike with 

 40 to 10 flowers. In Aphyllon each inflorescence is represented 

 by a single flower. 



6. It has been shown that the histological details, of stem and 

 leaf in the above progressive series of degrading parasitic types, 

 agree fundamentally with and verify the naked eye characters. 



7. The sepals of Scrophulariaceae and Orobanchaceae have 

 been found to show fundamentally similar structures and at 

 times to show similar condensation in the former from a five- 

 leaved to a four-leaved calyx through absorption of the odd se- 

 pal, as in Tozzia, Euphrasia and others. Lathraea, as an inter- 

 mediate type, may have a five to four-lobed calyx, and finally, 

 species of Orobanche and Boschniakia may show five to three se- 

 pals making up the calyx. 



8. In structure the stamens have been shown to constitute 

 an important link in the chain of evidence, for in all Gesneraceae 

 the anther lobes more or less converge and press against each 

 other at the apex and are rounded, as well as often divaricate at 

 their bases. In Scrophulariaceae and Orobanchaceae the mac- 

 roscopic and microscopic details proclaim progressive modifi- 

 cations in that the bases of the parallel anther lobes grow down- 

 ward into stiff awn-like horns, whose terminal cells are similarly 

 thickened throughout the series, and show a similar mode of 

 unequal thickening. In pollination, therefore, authors like 

 Ogle, Miiller, and Knuth demonstrate similar pollination ar- 

 rangements for Scrophulariaceae and Orobanchaceae that differ 

 markedly from those in Gesneraceae. 



9. Histologically, the sepals and stamens have been shown in 

 many of the types to bear tapered multicellular hairs inter- 

 spersed with capitate-glandular hairs that suggest strongly an 

 origin in common. 



10. The nectary in Gesneraceae is a cylindric structure that 

 appears either as a simple girdle, or as a series of connected 

 nectariferous knobs; very rarely is it a median unpaired swell- 

 ing. In Scrophulariaceae and Orobanchaceae the nectary is 



