MICHIGAN ACADEMY OF SCIENCE. 31}» 



iiway from one another, standing apart in a manner to remind one of the al«al 

 cells within a lielien. Very striking is the enormous porti<m of the phint 

 devoted to the organs of rei)roduction : whereas in Polysiplionia and other free- 

 living Ked Seaweeds the cystocarps and antherids occupy but a small part 

 of the plant, in Harveyella the organs of reproduction are very large and the 

 number of carpospores produced very great. 



If we accept the frequently suggested hypothesis that the Ascomyceteae 

 are derived from some ancestral form among the Rhodophyceao, they will rx- 

 seen to have carried out the simplification of the vegetative structure and 

 reduction in size of the cells in a manner similar to that for Harveyella, but 

 to an even greater degree. As in Harveyella, the reproductive structures are 

 strongly developed in most cases and occupy a large part of the plant. In 

 this class, we can follow out further than anywhere else the ultimate fate of 

 a group of plants that ceases to be holophytic. In some of the lichens, e. g., 

 CoUema, the sexuality is well marked, with free, non-motile, water-borne 

 siierms as in the Florideae and a well developed trichogyne. In Collemodes, 

 a nearly related lichen, the sperni remains permanently attaclied to the aiithe- 

 rid. In other related fungi the trichogyne and antherid unite directly without 

 the production of a separate sperm, in the Erysiphaceae the trichogyne is 

 dispensed with and finally with the. continual reduction in plant body and 

 concomitally of the reproductive structures we find the plant reduced to a 

 single cell and sexual reproduction to the union of two sucli cells to form a 

 single ascus. This is the case in some of the yeasts. All along this line we 

 lind apogamy frecpiently appearing as in some lichens, some species of I'yro- 

 nema, in many Sphaeriales and in the non-conjugating yeasts. At least, if i( 

 is not to be called apogamy it is the substitution of a union of other cells (or 

 nuclei) for those that .should unite in typical sexual reproduction. 



It is among the Anthophyta that w'e find again very well marked resulls 

 of panisifism. The mistletoes, such as Viscum and Phoradendron, are only 

 partially paratsitic, inasmuch as they still possess well developed leaves con- 

 taining chlorophyll. In the same family, however, occurs the genus Kazou- 

 mofskya with its dwarf leafless stems almost chlorophyll-less and numerous, 

 relatively large fruits. A large portion of the plant consists of an internal 

 branching stem lying in the inner bark and young wood of the host tree. In 

 some species this i)ortion continues to live for many years after the thicken- 

 ing of the l)ark of the host has become so great as to cut off all opportunity 

 for the formation of the external fruiting branches. 



In the rather closely related Balanophoraceae the reduction of the vege- 

 tative parts is carried still further, so that the plant develops as only a mass 

 of thin-walled pariienchyma with a few vascular bundles until sullicient food 

 has been ston-d up when a fungus-like, thick stem is produced consisting of 

 parenchyma and a few more or less circularly arranged vascular bundles. 

 This leafless stem is surmounted by a swH)llen apex, covered with very numer- 



