Mourning Lichen

Mourning Lichen

Mourning Lichen is the collective designation applied by the Vigil Scriptorium to the four lichen taxa permitted to grow unattended upon structural Mourning Glass: Mourning Moss (Cultivar M-44), Sorrow-lichen, the pallid form of Sigh-Moss, and the crustose variety catalogued as M-44c but never formally named. The term is administrative rather than botanical. Fourth Concordance, Annex 9 defines a Mourning Lichen as any organism whose removal from glass "occasion[s] a change in the glass's regard for the light," a phrasing the Office of Vitreous Accounts has disputed for one hundred and forty years without resolving it.

The four taxa are not closely related. They are grouped because they behave alike under the recording instruments of the Upper Mourning Floors: all four darken when read to, all four brighten when read to incorrectly, and all four will not grow on glass that has been catalogued under the wrong floor number.

Composition and the M-44c Dispute

Three of the four are settled. Sorrow-lichen is fruticose and grows in tufts at the joins of the archivization shelves; its inclusion is uncontested. Sigh-Moss is recorded in the appropriate schedules under its pallid form only, and the darker form, which the Scriptorium maintains is a different organism, is not. Mourning Moss is the most abundant and the most studied, owing to the distillate drawn from its lower-spire stock in the controlled maintenance of the glass itself.

The fourth taxon has no accepted name. It was first described in the margin of a shelf inventory by the clerk Adelard Quenn, who wrote only "crust, grey, does not answer to the name M-44" and appended a pressed specimen now lost. The Conservators' Bench has ruled twice that an unnamed organism cannot be a lichen of record; the Vigil Scriptorium has ruled twice that the glass recognizes it, and that the glass is the higher authority on what grows on it. Neither ruling has been withdrawn.

Behaviour Under Illumination

Mourning Lichen responds to light in a manner that the Observatory of the Ninth Diameter attributes to "recollection rather than nutrition." Placed under a lamp of standard issue, a colony will brighten over eleven minutes, hold, and then darken to a shade corresponding to the lamp's inscription. Because lamps are inscribed by the office that issues them, the shade functions as an unintentional record of provenance: conservators routinely determine which annexe a lamp came from by the moss that has answered it.

A colony read aloud to will darken within the hour, and will brighten again if the reading is found to contain an error and corrected. This property is formally recognized in the Protocol for Differentiating Agent Harvest, Annex 5, which permits the use of a flat of Mourning Moss as a witness to recensions of disputed documents. It is the only witness the Tower accepts whose testimony cannot be cross-examined and is, for that reason, the most frequently relied upon.

Collection, Restriction and the Midden Incident

Collection is confined to Catwalk 3 and to the two shelf aisles designated under Seventh Concordance, Article 12, which forbids removal of any living specimen from the Upper Mourning Floors without a chit countersigned by a Librarian. The chit requirement is old and mostly honored. In the winter of the year recorded as Fourth Concordance, Annex 9, a visiting examiner from the lower spires carried a flat of Moss past the last archive door without a chit and was not challenged, because the door in question had been sealed since the previous recension and no longer opened.

The examiner deposited the flat on the midden behind Spire Annex 7, where on the fourth night it grew across the whole of the midden's north edge, fused with a patch of Ink Lichen already established there, and produced a composite growth that answered to the name "M-44" and also to the name "ledger seventeen." The Office of Vitreous Accounts spent nine days separating the two and has since required that all flats leaving Catwalk 3 be carried upside down.

Disagreement Between the Concordances

The Third Concordance treats Mourning Lichen as inert, listing it in Schedule B among fixtures, and thus assigns its upkeep to the floor steward. The Fourth Concordance treats it as a party to the archive, and holds that a damaged colony is a damaged holding, to be reported on the same form as a broken shelf. Because both remain in force, a single damaged colony is regularly reported twice and repaired once, by whichever office arrives first and is subsequently held liable by the other.

"No office shall repair what another has reported, nor report what another has begun to repair; where both proceed at once, the lighter of the two shall withdraw."

— Seventh Concordance, Article 12

The rule depends on a weighable colony, and it is the practice of the Scriptorium to keep every colony faintly damp, on the reasoning that a removed lichen is lighter than one still growing.

Role in Mourning Glass Manufacture

Mourning Lichen is not a component of glass, but it is a necessary condition of its quiet. The dissolution of the older repositories, and the manufacture of Sigma-Glass from the processed particulates, were permitted only where the floor steward certified that no Mourning Lichen had been disturbed for a full recension. Certification for the Mourning Glass of the 44th Spire is still renewed annually by hand, in ink drawn from Sleeping Ink Lichen, and the original is kept in a case whose interior has not been opened since the count was reassigned.

Inside that case, according to the steward's standing note, the moss is doing well.