Cytology of the Teliospores, Basidia, and Basidiospores of Sphenospora Kevorkianii Linder

SUMMARY

1.	The cytomorphological development of the teliospores of Sphenospora kevorkianii is essentially like that described for Puccinia, except that the spore septum is vertical and the spore wall remains thin. At maturity each cell contains a single large fusion nucleus.
2.	Paraphyses are produced in large numbers from the same cells in the telium that produce the teliospore initials. They are generally unicellular and binucleate, but are sometimes two-celled.
3.	Each cell of the teliospore germinates to produce a basidium apically. Two meiotic divisions take place in the basidium, the nucleolus being discharged into the cytoplasm during the first division.
4.	Four nuclei are produced in the developing basidium, which generally becomes three-celled, with one nucleus in each of two cells and two nuclei in a third cell. The septa are produced in an irregular manner, generally not directly correlated with the nuclear divisions.
5.	Two- and four-celled basidia are also produced.
6.	Some of the nuclei in the developing basidia appear to be cut into as they get in the way of the developing septa.
7.	Mature basidia produce from one to four basidiospores, usually three. Spores produced by uninucleate cells of the basidim are uninucleate. Those produced by the binucleate cells are binucleate. There appears to be no nuclear division in the basidiaspores at this time.
8.	The taxonomic treatment of the genus Sphenospora by Dietel seems to be the most acceptable at present. Thus the genus is retained in the tribe Ravenelieae of the Pucciniaceae.

The author is very grateful to Dr. C. W. Edgerton, who made the photographs for this paper.