A Monadine parasitic on Saprolegnieae 1. BY MARCUS M. HARTOG, M.A., D.Sc. With Plate XXII. B. IN N my cultures of Saprolegnicae I was for a long time perplexed by structures which looked like abnormal spores with a gigantic nucleus, and which I at first really regarded as such. However, on making cover-glass cultures of 'cuttings' (fragments of mycelium removed with a blunt knife) with young oogonia, I found to my cost that they were parasitic organisms, which demanded careful study. They soon turned out to be members of Cienkowski's group 'Monadineae,' now regarded as the close allies of Myxomycetes; and, so far as can be judged from the vegetative conditions and zoocysts, are referable to the well-named genus Pseudospora Cienk.2, created in 1865, to receive very similar parasites on the green Conjugates and Desmids. The organism is so abundant in cultures of Saprolegnieae that it could not escape the notice of previous observers. Pringsheim3 first saw the zoocysts in Saprolegnia (Leptomitus) lactea, and figured them in company with the undestroyed cellulin-corpuscles in an empty hypha. He describes them as 'Eine grosse Anzahl stark mit Inhalt erfüllter kugeliger Zellen . . . die offenbar keine Schwärmsporen sind. Ihre Bedeutung ist mir noch unbekannt.' Lindstedt in 1872, in his 'Synopsis Saprolegniacearum,' recognised their true nature. In älteren Fäden deren fand 1 Read at the British Association, Newcastle-on-Tyne, 1889. 2 Beiträge zur Kenntniss der Monadinen, in Schultze's Arch. f. Micr. Anat. i. 213. 3 Jahrbücher, II. 234, t. xxiii. f. 6. [Annals of Botany, Vol. IV. No. XV, August 1890.] A Monadine parasitic on Saprolegnieae1. BY MARCUS M. HARTOG, M.A., D.Sc. With Plate XXII. B. IN my cultures of Saprolegnicae I was for a long time. perplexed by structures which looked like abnormal spores with a gigantic nucleus, and which I at first really regarded as such. However, on making cover-glass cultures of 'cuttings' (fragments of mycelium removed with a blunt knife) with young oogonia, I found to my cost that they were parasitic organisms, which demanded careful study. They soon turned out to be members of Cienkowski's group 'Monadineae,' now regarded as the close allies of Myxomycetes; and, so far as can be judged from the vegetative conditions and zoocysts, are referable to the well-named genus Pseudospora Cienk.", created in 1865, to receive very similar parasites on the green Conjugates and Desmids. The organism is so abundant in cultures of Saprolegnieae that it could not escape the notice of previous observers. Pringsheim first saw the zoocysts in Saprolegnia (Leptomitus) lactea, and figured them in company with the undestroyed cellulin-corpuscles in an empty hypha. He describes them as Eine grosse Anzahl stark mit Inhalt erfüllter kugeliger Zellen . . . die offenbar keine Schwarmsporen sind. Ihre Bedeutung ist mir noch unbekannt.' Lindstedt in 1872, in his Synopsis Saprolegniacearum,' recognised their true nature. 'In älteren Faden deren fand 1 Read at the British Association, Newcastle-on-Tyne, 1889. * Beitrage zur Kenntniss der Monadinen, in Schultze's Arch. f. Micr. Anat. i. 213, 'Jahrbücher, II. 234, t. xxiii. f. 6. [Annals of Botany, Vol. IV. No. XV, August 1890 ] |