ascogenous

In H. rutilans, however, both sexual organs are absent and the ascogenous hyphae arise apogamously from the ordinary hyphae of the mycelim.

The ordinary mycelium is the gametophyte since it bears the ascogonia and antheridia when present; the ascogenous hyphae with their asci represent the sporophyte since they are derived from the fertilized ascogonium.

In other cases the ascogenous hyphae arise directly from the vegetative hyphae.

The cytological details of development of the perithecia are not well known; most of them appear to develop their ascogenous hyphae in an apogamous way without any connexion with an ascogonium.

Thus in Penicillium, Eurotium, Erysiphe, &c., hyphal ends which are the initials of ascogenous branches, are invested by closely packed branches at an early stage of development, and the asci develop inside what has by that time become a complete investment.