Jack Frost: the history of an albino cross and what its spores look like
Few lines have spread through the microscopy community as fast as Jack Frost. It arrived in the early 2020s, it is entirely white, and it has become a parent to a whole family of crosses. Here is where it came from and why it is worth a slide.
01Where Jack Frost came from
Jack Frost is a Psilocybe cubensis cross of two albino lines: True Albino Teacher (TAT), itself an albino isolation of Golden Teacher, and Albino Penis Envy (APE). The cross came out of the American hobby breeding community and circulated from around 2020, with the name a nod to the frosted, white-on-white appearance of the fruiting body. As with most community-bred lines the exact first release is undocumented, so treat the date as approximate.
What is not in doubt is the parentage, because it shows on the slide. Both parents are albino, and Jack Frost inherits that in full: caps, gills and spores without pigment.
02Under the microscope
Jack Frost spores are the classic cubensis shape, subellipsoid and thick-walled with a germ pore, but they are almost colourless. On a slide next to a pigmented line the contrast is immediate: where a Golden Teacher drop shows purple-brown spores, Jack Frost shows translucent, glassy ones. Close the condenser diaphragm and lower the light and the walls resolve clearly. It is one of the best specimens in the library for learning to see unpigmented spores, and a print from it is pale grey rather than the usual purple-brown.
Because both parents carry the Penis Envy trait of thin spore deposits, Jack Frost prints can be light. The library's syringes are made from carefully collected prints for that reason.
Where a Golden Teacher drop shows purple-brown spores, Jack Frost shows translucent, glassy ones.
03The Jack Frost family in the library
Jack Frost has become one of the most used parents in modern breeding, and several of its descendants are catalogued here with their lineage on the card:
- Jack Frost 324, a What The Fungi isolation selected for size from the original line.
- Toque x Jack Frost, an isolated cross that pairs it with the Toque line.
- Shredder (Jack Frost x Mayahuel), an Australian cross that became a MycoWorld favourite.
- Oaxacan Frost (Jack Frost x Maria Sabina), a What The Fungi original noted for its very large gills.
- Frosty Pearlz 393 (Jack Frost x Pearly Gates), one of What The Fungi's first two crosses made from monokaryotised cultures.
- King Cold (Jack Frost x Thrasher) and Lord Frieza (SV-10 x Jack Frost), isolates from the PsyTeamUnited DBZ collection.
Line them up on the lineage explorer and you can follow the albino trait through each generation.
04Why breeders reach for it
An albino parent lets a geneticist track a cross visually: if the offspring stay white, the albino trait has carried. Jack Frost is stable, well documented and easy to recognise, which is why it turns up on so many cards as a parent. For microscopy that means a large family of related specimens you can compare directly, all sharing the same pale spore signature.
Questions people ask
What is Jack Frost a cross of?
True Albino Teacher (an albino isolation of Golden Teacher) and Albino Penis Envy. Both parents are albino and the trait carries through.
Why are Jack Frost spores so hard to see?
They carry almost no pigment. Use a lower light level and a partly closed condenser diaphragm to bring up the spore walls.
Does MycoWorld stock Jack Frost?
The original line and several of its crosses rotate through the library. Toque x Jack Frost is an isolated cross currently in stock, and the strain pages list every Jack Frost descendant.