Lindsay again wrote today's entry:

Thank you to marcella2@Flickr for today's photopgrah (particularly if fungus is your fancy)! Marcella2's photo stream on Flickr is definitely worth a gander (original image | Botany Photo of the Day Flickr Pool)!

Xylaria hypoxylon is a wood-dwelling ascomycete commonly known as stag's horn or candle-snuff fungus (previously featured on BPotD here: Xylaria hypoxylon). It is identified by its erect antler-like stroma; these are black at the base but whitish throughout the many body and upper branches. The branches are the site of asexual spore production, also known as conidia (note, though, that these are produced at a microscopic level).

Xylaria also produces sexual spores, via perithecia. The perithecia are embedded (in the case of Xylaria hypoxylon) in the black base of the stroma. From each perithecium, spores are released one by one when ripe through a small pore, called the ostiole.

Art resource link (added by Daniel): Three people have forwarded me the following link so far, so I thought I should share it more widely: Christopher Niemann's Bio-Diversity weblog posting on the New York Times.