4 BOTANICAL GAZETTE [july 



Dittschlag (10) was the first to describe sexual fusions in an 

 aecidium of the cup type. He found cell fusions at the base of the 

 young aecidium of Puccinia Fakariae, but was unable to trace 

 completely the origin of the fusing cells. A single sterile cell was 

 sometimes found above each gamete, but was not always present. 

 Trinucleated basal cells were found that apparently arose from 

 the fusion of three cells, and these basal cells gave rise to chains 

 of trinucleated aecidiospores and intercalary cells. He further 

 described branching basal cells for the first time. The primary 

 basal cell formed a bud on the lateral wall, and two daughter nuclei 

 from the preceding conjugate division passed into the bud. The 

 bud enlarged further and then the nuclei proceeded to divide and 

 give rise to a second chain of spores. His description of the origin 

 of the peridium agrees with that of Richards. 



Hoffman (15) studied the development of the aecidium of 

 Endophyllum Semperoivi, a species that completes its life cycle with 

 the production of a single spore form, an aecidio-teleutospore, 

 besides the spermatia. He distinguished two kinds of tissue in the 

 young cup. The first tissue formed disintegrated to provide room 

 for the development of the spores, and a second tissue, the "Paar- 

 ungsgewebe," was then formed at the base of the primordium. The 

 cells of this tissue were conspicuous for their size and the density 

 of their cytoplasm, and were borne in filaments that had their long 

 axes parallel to the surface of the leaf. Fertilization was accom- 

 plished by the dissolution of the adjoining cell walls between two 

 gametes and perpendicular basal cells resulted. He also found 

 triple cell fusions and trinucleated basal cells and spore chains. 

 He thinks that one of the nuclei in a trinucleated spore eventu- 

 ally disintegrates, but obtained no convincing evidence of this. 

 He also found branching basal cells like those described by 

 Dittschlag, and states in addition that the conjugate nuclear 

 division that precedes the formation of the branch produces two 

 pairs of nuclei of unequal size. The smaller pair enters the branch 

 and the larger pair remains in the original half of the basal cell. 

 His figures of this process are not at all convincing. 



The author (12) has described the nuclear development of the 



