1) Perithecial opening 2) Pore 3) Small aperture 1) Stoma 
An ostiole is a small hole or opening through which algae or fungi release their mature spores. The term is also used in higher plants, for example to denote the opening of the involuted fig inflorescence through which fig wasps enter to pollinate and breed. ...
a small opening
1. A neck-like structure in an ascocarp, lined with pariphyses, and terminating in a pore. 2. The opening of a pycnidium. 
• (n.) Any small orifice. • (n.) The exterior opening of a stomate. See Stomate.
An opening or pore. ... (09 Oct 1997) ... 
Os'ti·ole noun [ Latin ostiolum a little door, dim. of ostium a door: confer French ostiole .] (Botany) (a) The exterior opening of a stomate. See Stomate . (b) Any small orifice. 
A small bodily aperture, orifice, or pore.
[n] - a small pore especially one in the reproductive bodies of certain algae and fungi through which spores pass
noun a small pore especially one in the reproductive bodies of certain algae and fungi through which spores pass