]40 



DIVISION II. — COURSE OF DEVELOPMENT OF FUNGI. 



thorough investigation; Pringsheim's Pythium endophytum 1 and Schcnk's Achlyo- 



geton 2 are certainly very near il. 



Literature of the Ancylistcac. 



Cornu, Monogr. des Saprolegnie'es in Ann. d. sc. nat. scr. 5, XV, and in Bull. soc. bot. 



de France, XVI (1869), p. 222 ; — Id. , cited in Sachs, Traite" de Bot. translated by 



Van Tieghem, p. 32S. — See also Schenk, Ucber contractile Zellen, Wiirzb. 1858, p. 9. 



ZOPF in Bot. Ztg. 1S79. i>. 351. 



Pfitzer in Monatsber. d. Berlin. Acad. 1872, p. 351. 



MONOBLEPHARIS. 



Section XXXIX. The aquatic genus Monoblepharis with three species, which 

 at present has been examined only by Cornu 3 , is related to the Peronosporeae. 

 These plants, according to Cornu's short and somewhat incomplete description, 

 resemble the Pythieae in their vegetative structure and in their mode of life. They 

 form on their thallus sporangia with swarm-spores, and the latter originate and 



escape, not in the manner of 

 Pythium, but in that of Phyto- 

 phthora, &c. and have only one 

 cilium. Oogonia and anther- 

 idia are terminal or intercalary 

 on the branches of the thallus ; 

 their disposition, which varies 

 in the different species, agrees 

 with that of some species of 

 Pythium; Fig. 67 shows it in 

 Monoblcpharis sphajrica. The 

 points in which M. differs from 

 Pythium appear in its further 

 development. Firstly, the whole 



67. Monoblcpharis sfhacrica, extremity of a filament bearing an oogonium OI the pi'OtOplaSm OI the OOgO- 



e and an antberidium a. i. before the 1 I the oosphi-p ids. .... .. 



osphere fonni ipermatozoids s escaping from the antheri- niUlll Willi ltS ntimCIOUS Oil - 



dium. 3. ripe oospore in the oogonium which is borne "ii the empty antberidium. . . . r 1 . . 



After cornu. Magn.8oot.-i globules is transformed into the 



oosphere without separation of 

 periplasm and with diminution of volume, and as this takes place the wall of the 

 oogonium opens at its upper end. Secondly, a few swarm-cells (spermatozoids) 

 are formed by division of the protoplasm in the antheridium; the spermatozoids 

 escaping through an aperture in the wall of the antheridium move with a gliding 

 motion over the wall of the oogonium, till one of them finds its way through the 

 aperture to the oosphere and coalesces with it. The oosphere is thus fertilised and 

 an investing membrane is formed, which subsequently becomes strongly thickened 

 and rough with warts on the outer surfat e ; in this state the body is a resting oospore, 

 the further development of which is unknown, but can hardly differ from that of the 

 Peronosporeae. 



1 Jahrb. f. wiss. Bot. I. Bot, Ztg. 1859, p. 39S. 



3 Ann. d. sc. nat. ser. 5, XV, 1 S 7 -• . 



