RT Journal Article SR Electronic(1) A1 Fletcher, J.YR 1971 T1 Conidium Ontogeny in Penicillium JF Microbiology, VO 67 IS 2 SP 207 OP 214 DO https://doi.org/10.1099/00221287-67-2-207 PB Microbiology Society, SN 1465-2080, AB After fixation with permanganate or with glutaraldehyde and osmium tetroxide, phialide walls of Penicillium clavigerum Damelius, P. claviforme Bainier and P. corymbiferum Westling were electron-transparent with a thin, electron-opaque surface layer. The phialide apex was closed by a hollow, plug-like structure of wall material. A conidium initial was formed by distension of this plug. The conidium protoplast was delimited from the phialide protoplast by a perforate septum. A new wall was formed round delimited conidium protoplasts between the protoplast and the original wall. The original wall round older conidium protoplasts was of different appearance from the original wall around more recently delimited protoplasts. Conidium chains were covered with a thin, electron-opaque surface layer. Phialides were uninucleate., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-67-2-207