Mourning Moss — The Tower

Mourning Moss (Bryum lamentum, designated Cultivar M-44 under Cultivar Standards) is a non-photosynthetic bryophyte endemic to the lower sections of the Moss-Growth Spire on Floor 14,022. It is classified as a counter-lumenic moss, characterized by its absorptive properties and its documented antagonistic relationship with standard lumen-moss cultivars.

“…and the specimen, upon contact with the distillate, did not decay but rather entered a state of profound optical silence, as if remembering a light it had never seen.”

— Excerpt from the observational log of Keeper Arin, regarding the initial spirelocation of the primary growth cluster, dated 14-022.307.

Physical Description & Habitat

Mourning Moss presents as a dense, velvety mat of near-black filaments, with a typical growth height not exceeding 3 millimeters. Its texture is described as "cold velvet" in the field manuals. It exhibits no bioluminescence and absorbs approximately 94% of incident light across the visible spectrum, rendering its immediate vicinity noticeably dimmer. It thrives in environments of high acoustic dampening and low airflow, most notably within the structural interstices of the designated Moss-Growth Spire and, according to maintenance logs from the Schism of the Eastern Stacks, within the lower alcoves of the Eastern Auxiliary Ladder adjacent to Spire Annex 7.

Chemical & Reactive Properties

The moss's defining characteristic is its production of a complex organic compound, Lamentine, which can be extracted via cold distillation. This distillate has two principal documented effects:

[[Sublimation of Forgotten Resin: As per Concordance Addendum 707.β, a distillate of Mourning Moss causes Forgotten Resin to sublimate without residue, a property utilized in archival restoration protocols for sealed containers.
[[Induced Dormancy in Creeping Phosphor-Moss (Creeping Phosphor-Moss): Sustained exposure (33–37 days) to active Mourning Moss, or direct application of Lamentine, forces Creeping Phosphor-Moss into a dormant, non-luminescent state. This is the basis for the "Moss Quarantine" procedures outlined in Guild Standard 114-Delta-7c.

The moss itself enters a brittle, crystalline phase if exposed to light exceeding The Standard Lumen for more than 12 consecutive hours, a vulnerability noted by Selena Moss in her dissent regarding fixed photoperiods.

Industrial & Archival Applications

Processed Mourning Moss is a regulated substrate with several specialized uses within the Tower's archival systems.

Echo-Glass Production: Particulate matter derived from processed Mourning Glass of the 44th Spire is infused into glass matrices to create Echo-Glass, used in the Spire of Cartographic Echoes for resonance mapping. The Mourning Glass itself is a product of Source Extraction performed on raw Mourning Moss.
Sigma-Glass Precursor: The same particulate matter is a listed source material for the manufacture of Sigma-Glass, though the relevant Concordance (Third, Clause 4041) is in direct contradiction with the Second Concordance’s Annex G, which prohibits the use of "lament-derived particulates" in permanent structural glazing.
Acoustic Treatment (Related Phenomena): While not directly comprising the substance, the growth substrate for the so-called Silent Moss found in Aperture Delta is noted to be chemically congruent with spent Mourning Moss colonies, suggesting a transformative lifecycle stage.

Controversies & Administrative Status

The cultivation and application of Mourning Moss are subjects of ongoing bureaucratic contention. Proponents, chiefly the Guild of Luminal Regulators, cite its utility in controlling invasive luminous moss species and its irreplaceable role in Echo-Glass. Opponents, including the Archive of Unstable Media, argue that its light-absorptive properties pose a passive threat to adjacent illuminated collections and that its very presence subtly alters the subjective passage of time for cataloguers working nearby, a claim supported by the (disputed) findings documented in the Compendium of Unheeded Dissents.

The primary growth site remains the Moss-Growth Spire on Floor 14,022, with harvesting permitted only under the conditions of Standard 114 Delta 7b, despite the standard's primary focus being on lumen-moss nutrition. This regulatory overlap is a frequent point of inter-departmental grievance.