SAPROI.EGNIA 51 



gether for a lonij time hoforo coinpIotcK' fusini;; and losing (lu'ir identity. 

 Xo reduction of ehroniosonie nimiber takes place in the antheridia and 

 oogonia before fertilization; though riot observed, such reduction prob- 

 ably occurrs in the germinating egg. For other cytological data see Dan- 

 geard ('90), i^. in, pi. 6, figs. 1-5. 



8. Saprolegnia monoica var. glomerata Tiesenhausen. Arch. f. 

 Hydrobioiogie und Planktonkunde 7: 277, figs. 6-8. 1912. 



Pl.\tes 4 .\ND 13 



The typical Chapel Hill strain of this variety may be described as 

 follows (Xo. 7 of April 3, 1913): 



Growth moderately extensive, the hyphae not very robust; sporangia 

 abundant, cylindrical or long club-shaped, later ones more irregular, 

 proliferating from within or not rarely from cjnc side also, \'arying greatly 

 in size, rarely so small as to have only a single row of spores; spores 

 lo-i i'^ in diameter; gemmae abundant or few, often in moniliform chains, 

 pear-shaped or irregularly club-shaped, often nodulated or branched, 

 quickly forming spores when brought into fresh water; oogonia abun- 

 dant, usually lateral on short stalks which are mostly a quarter to equally 

 as long as the diameter of the oogonia, rarely intercalary, occasionally 

 terminal and then usually cylindrical in old sporangia; wall colorless, 

 moderately thick, the pits. few or numerous in the same culture, and 

 rather conspicuous, 5.5-7^. in diameter. Eggs centric, generally one, 

 two, or four, occasionally si.x or eight, rarely 20 (or more?), diameter 

 24-311A; usually about 25-27(1. Antheridial branches short, typically 

 clustered and contorted, often branched, arising androgynously from 

 the main branches near the oogonia or at times from the oogonial stalks, 

 not rarely reaching also to nearby oogonia on other threads (diclinous) ; 

 antheridia pear-shaped or tuiierous, one or more on every oogonium; 

 antheridial tubes formed. 



The plant is evidently rare in Chapel Hill, as we have recognized 

 it with certainty only once — in the brook in Battle's grove (X^o. 7 of 

 April 3, 1912). Also reported by Humphrey from Cambridge and 

 Amherst, Massachusetts, as S. monoica (see below). It is easily dis- 

 tinguished from 5. Jerax, which seems nearest, by the short, clustered, 

 androgynous antheridial branches with antheridia on every oogonium. 

 The antheridia are usually se\eral, sometimes numerous and of both 

 androgynous and diclinous origin, nearly always one or more androg- 

 ynous ones on an oogonium and very often diclinous ones also. 



There are important differences between this plant and European 

 interpretations of the typical S. mouoica, these appearing in the larger 

 size and fewer number of the eggs in the American form on the average. 

 Humphrey refers to 5. mouoica a plant with eggs about 26[l on the 

 average, agreeing with ours, and he gives the number as "commonly not 



