272 THE LOWER FUNGI— PHYCOMYCETES 



to be ondogenou.s in chanicter, they are here so regarded from 

 analogy with those of the other genera incorporated in the family. 

 Several other genera, known only in the asexual stage, appar- 

 ently belong near Dispira. One of these, Dimargaris van 

 Tieghem (1875: 154, figs. 165-172), a monotypic genus based on 

 D. cristalligena, possesses fertile hyphae so strikingly similar to 

 those of Dispira americana that discovery of intermediate species 

 would necessitate the merging of the two genera. The other 

 genera are Kickxella Coemans (1862: 155) [Coemansiella 

 Saccardo, SyllogeFnngorum, 2: 815], il/ar^ewseZ/a Coemans (1863: 

 536), Spinalis Vuillemin (1904 h: 26), Saitomyces Ricker {Jour. 

 Mycol., 12: 61, 1906), and Coemansia van Tieghem & le Monnier 

 (1873:392). 



2. Piptocephalis de Bary (1866: 356). 



IVIycelium parasitic on other Mucorales, running over the host 

 hyphae and attached to them at intervals b}' swollen suckers 

 from which delicate, filamentous haustoria penetrate the host 

 cell; fertile hyphae erect, cylindrical, septate, repeatedly dichot- 

 omously branched; ultimate branches terminally more or less 

 swollen to form deciduous capitate enlargements over whose 

 surface sterigmata project bearing cylindrical rod-like sporangia; 

 sporangia at maturity forming simultaneously a single row of 

 spores which appear, after the dissolution of the sporangial 

 wall, as a row of conidia; in one species, P. monospora Mangin 

 (1899: 376), the sporangium containing only a single spore, in 

 another, P. microcephala van Tieghem (1875: 148), only two; 

 zygospore globose, rough, formed by the enlargement of a bud 

 which develops from the point of union of two clavate game- 

 tangia which come in contact at their apices after the fashion of 

 a pair of tongs (Fig. 100). 



About a dozen species have been described, the majority by 

 van Tieghem (1875: 137). No recent monograph of the genus 

 has appeared, the best general treatment being that of Fischer 

 (1892: 287). 



An unusual interpretation of the homologies of the asexual 

 stage in this genus and the others of the family is given by 

 Gaumann (1926: 103). He regards the capitate enlargement at 

 the apex of the fertile hypha as the sporangium, and terms the 

 cylindrical branches in which the spores are borne extrasporangial 

 partial sporangia. His point of view is the same with respect 



