Rozella

Rozella species grow inside their hosts. At first, the thallus is unwalled and indistinguishable from the host. As growth continues, the thallus will either form a zoosporangium using the wall of the host or a thick-walled resting spore that can be smooth or spiny. From its conception, there have been two divergent morphologies within the genus. Monosporangiate species form a single zoosporangium within the host. Polysporangiate species form multiple zoosporangia that are separated with septa. ==Ecology==

Most described species are parasites of Oomycota, Chytridiomycota, and Blastocladiomycota. Rozella itersoniliae is a parasite of the basidiomycete Itersonilia perplexans, though some authors doubt its placement in the genus. Rozella coleochatis parasitizes a species of the green alga Coleochaete. ==Taxonomy==

The genus name of Rozella is in honour of (1833–1900), who was a French Administrator and high official in the Ministry of Finance of France, botanist (Bryology, Mycology and Algology). French mycologist Marie Maxime Cornu in 1872 circumscribed the genus to accommodate four species: R. septigena, R. monoblepharidis-polymorphae, R. rhipidii-spinosi, and R. apodyae-brachynematis. Later authors shortened these to R. septigena, R. monoblepharidis, R. rhipidii, and R. apodyae. Based on the monosporangiate/polysporangiate differences in development and morphology, Fischer circumscribed Pleolpidium using R. monoblepharidis as the type and leaving R. septigena as the type species in Rozella. Clemonts and Shear also designated R. setigena as the type of Rozella in 1931. Later, R. allomycis and R. achlyae were described, and later authors treated Pleolpidium as a synonym of Rozella. Batko later circumscribed Skirgiella to accommodate the polysporangiate species and retained the monosporangiate species in Rozella. However, because this removed the type from the genus, it was nomenclaturally invalid. Additionally, molecular phylogenies consistently group monosporangiate and polysporangiate species together, thus validating the monophyly of the genus. There is considerable debate over the name of this larger clade: Cryptomycota, Rozellida, Rozellamycota. ==Notable species==

Rozella allomycis Rozella allomycis is one of the most extensively studied species; Host mitochondria are recruited to the host-parasite interface. Sometimes, host mitochondria are found within the R. allomycis protoplast within three-membrane vacuoles, which is evidence the R. allomycis protoplast is phagocytizing the host cytoplasm as it grows. As it grows, the R. allomycis protoplast completely fills a portion of the host, which is separated by a host septum. The protoplast develops into a zoosporangium and releases zoospores. As the infection progresses, R. allomycis protoplasts will instead form resting spores with thick, spiny walls. Rozella rhizoclosmatii A species of Rozella on Rhizoclosmatium was first reported in a molecular phylogeny simply as Rozella ex Rhizoclosmatium ==Species==

• Rozella achlyae Shanor 1942 • Rozella allomyces Nabel 1939 • Rozella allomycis Faust 1937 • Rozella apodyae-brachynematis Cornu 1872 • Rozella barrettii Karling 1942 • Rozella blastocladiae (Minden 1911) Sparrow 1938 • Rozella canterae Sparrow 1960 • Rozella chytriomycetis Karling 1946 • Rozella cladochytrii Karling 1941 • Rozella coleochaetes Sparrow 1965 • Rozella cuculus (Butler 1907) Sparrow 1938 • Rozella diplophlyctidis Karling 1987 • Rozella endochytrii Karling 1941 • Rozella irregularis (Butler 1907) Sparrow 1938 • Rozella laevis Karling 1942 • Rozella longicollis Karling 1966 • Rozella longisporangia Willoughby & Rigg 1983 • Rozella marina (Sparrow 1936) Sparrow 1938 • Rozella monoblepharidis-polymorphae Cornu 1872 • Rozella multimorpha Letcher et al. 2017 • Rozella parva Canter 1969 • Rozella polyphagia (Sparrow 1933) Sparrow 1938 • Rozella rhipidii-spinosi Cornu 1872 • Rozella rhizoclosmatii Letcher & Longcore 2017 • Rozella rhizophlycti Karling 1942 • Rozella rhizophydii Karling 1944 • Rozella septigena Cornu 1872 ==References==