Morphology. 9 



orders, have degenerated so far from the ancestral 

 stock as to have lost the power of forming chlorophyll, 

 and in consequence, like the fungi, have become 

 parasites or saprophytes, the bird's-nest orchis, 

 Neottia nidus-avis, and toothwort, Lathrsea sqiiamaria, 

 are examples, but in most such cases, these degene- 

 rate species still retain the same general structure, 

 so that there is but little difficulty in consigning them 

 to their proper orders, although in some instances 

 these phanerogamic departures from the typical stock 

 have become so modified as to present but slight 

 affinities with any of the normal groups. The fungi, 

 in like manner, appear to have descended from 

 chlorophyll-producing ancestors, but such ancestors 

 were very much lower down, or nearer the starting- 

 point of plant life, than flowering plants, and are 

 represented at tlie present day by the simple green 

 algas furnished with sexual organs, illustrated by such 

 genera as VaiicUei'ia. The Sajproleyniese, mostly 

 aquatic fungi, and the Feronosporex, inhabiting the 

 tissues of living plants, may be considered as illustra- 

 tions of forms near the starting-point of the fungi 

 proper, and omitting for the moment the presence of 

 chlorophyll in the one case, and its absence in the 

 other, the above-mentioned algal and fungal forms 

 present many important morphological features in 

 common. In both there is the same long, irregularly- 

 branched vegetative portion, in both the tips or 

 interstitial portions become swollen into a more or less 

 globose receptacle or oogonium, the female organ of 

 reproduction, into which the protoplasm becomes 

 aggregated and retained by the formation of septa 



