Roccella tinctoria

Roccella tinctoria

Roccella tintoria (Roccella tinctoria DC.) is a lichen belonging to the Roccellaceae family.

Systematics –
From a systematic point of view it belongs to:
Eukaryota Domain,
Kingdom Fungi,
Ascomycota Division,
Pezizomycotina subdivision,
Arthoniomycetes class,
Arthoniales Order,
Roccellaceae family,
Genus Roccella,
R. tinctoria species.
The terms are synonymous:
– Lecanora tinctoria (DC.) Czerwiak .;
– Roccella arnoldii Vain .;
– Roccella canariensis Darb .;
– Roccella canariensis var. vincentina (Vain.) Zahlbr .;
– Roccella dichotoma (Pers.) Darb .;
– Roccella fastigiata Bory;
– Roccella guanchica Feige & Viethen;
– Roccella phycopsis Ach ..
– Roccella patellea Mixed;
– Roccella tuberculata var. vincentina Vanin .;
– Roccella vincentina (Vain.) Follmann.
Within this species, the following varieties and forms are recognized:
– R. tinctoria. var. portentous;
– R. tinctoria. var. subpodicellata;
– R. tinctoria. var. dry cleaners;
– R. tinctoria. F. coplanar;
– R. tinctoria. F. dry cleaner.

Etymology –
The term Roccella comes from the name of the Florentine family of the Rucellai, in ancient Oricellai, who controlled its import from the Levant from the 12th to the 13th century.
The specific epithet tinctoria comes from tíngo dye: used to dye fabrics or for other uses.

Geographic Distribution and Habitat –
Roccella tinctoria is a lichen found in the Mediterranean basin, especially in the western area and which grows along the sea coasts.
Its habitat is that of strongly inclined surfaces on siliceous rocks subject to humid sea winds laden with salt. The species can be both fertile and sorediated (see Tehler & al. 2009), but all the Italian specimens, limited to a few sites in Tyrrhenian Italy, are sorediated.

Recognition –
Roccella tinctoria is a lichen that has a fruticose, rigid, brown to grayish-brown thallus, consisting of 3-20 cm long branches, terete, foveati or smooth coming from a common support, generally (in Italy) sorediati and free of apothecia (fertile specimens are usually exorediate); lateral sorals, circular, white, strongly convex.
Hyphae cortex arranged anticlinally which do not form a conspicuous palisade plectenchyma, covered by an amorphous epicortex; medulla oblongata white, but usually streaked with brown or black.
Very rare apothecia in Italian material, lateral, sessile, rounded, with black disc, but often white-pruinose, finally cracked and thin margin.
Epithecium almost colorless; colorless hymenium; branched and poorly anastomosed paraphysoids, c. thickness 2 mm; hypothecium dark brown to black.
Asci with 8 spores, thick walls, fissitunicate, with internal beak and a small blue K / I + ring at the thickened apex.
Ascospores 3-septate, hyaline (overripe spores often light brown), oblong-fusiform, slightly curved, 21-27 x 5-6 µm.

Cultivation –
Roccella tinctoria is a lichen with a mainly asexual reproductive strategy, for soredi or soredi-like structures (e.g. blastids) and more common in areas with a hot-humid climate.
It appears as a group of cylindrical, branched and knotty filaments, of a yellowish white color that tends to become brown over time.
It has also been harvested in its natural state for centuries to produce dyes.

Customs and Traditions –
Roccella tinctoria is a lichen that was first described by Augustin Pyramus de Candolle in 1805.
However, it was already known since ancient times because from it, and still today, coloring substances called oricelli and litmus (or laccamuffe) were obtained.
The production process of this dye was a secret and led to the wealth of the weavers of Grainville-la-Teinturière and the Rucellai family of Florence.
It has been speculated that the abundance of Roccella tinctoria in the Canary Islands offered a reason for profit to Jean de Béthencourt during his conquest of the islands.
A letter, addressed in 1768 to the viceroy of Sardinia by the company “Le Clerc & C.” in London, reveals the events of a brief but thriving trade that was created in the Maddalena archipelago in the years immediately following the establishment of the community.
The document, kept in the State Archives of Cagliari (Secretariat of State – Series II – vol. 1275) is a request for the exclusive extraction from the “Isole de ‘Carruggi” of a lichen of the “roccella” genus advanced by the English company after the discovery in Sardinia of the precious vegetable.
In March 1768, during a survey of the archipelago, occupied by the Piedmontese for just five months, Professor Plaza, surgeon and botanist, sent by Carlo Emanuele III, with the task of studying the climate, the soils and the spontaneous flora at the in order to identify those crops of easy acclimatization and of high commercial value that could have been implemented in Sardinia, he had the good fortune to identify the “Roccella tinctoria”, which was widely attractive on European markets and especially on the English market. The lichens of the genus “oricella” or “roccella” were in fact highly sought after for the dyeing of wool and silk fabrics and for the cold coloring of marbles and alabasters that were carried out in Florence, Paris and Amsterdam. The British, then, made extensive use of it to obtain the bright red color of military uniforms and the “red jackets” of the Royal Guard.
The Plaza collected an abundant sample and sent it to the viceroy, communicating the discovery and letting him know which plant the island possessed. The sample, sent to Turin, was analyzed by Professor Allione who recognized the validity of the vegetable as a dyeing plant and advised its exploitation. A one-quintal bale was immediately collected which, sent to London, was tested with such success that the British, who until then had imported lichens from the Canaries and North Africa, showed interest in the product so much that the company “Le Clerc & C. ” he made an order of 30 quintals asking, as we have seen, the exclusivity for the extraction which was never granted.
The “fever of the rock” was immediately ignited in the archipelago and many Maddalenians engaged in the search for the precious plant on all the rocks and ravines of the islands. The lichen, which the islanders called Tramontana grass, was bought by Genoese merchants who, sensing the lucrative deal, rushed to La Maddalena, setting up a collection center on the island. In the early years it was possible to ship over 200 quintals and the annual export from Sardinia, after the Plaza had also identified it in Asinara and other locations on the north coast, was around 300 quintals. Soon the Sardinians, realizing the gains that the Ligurians made behind them by concentrating the lichen in Genoa and reselling it at very high prices, organized themselves and La Maddalena became a base for the shipment of the product to the markets of Marseille and Livorno.
But like all gold rushes, the adventure of the “roccella” was destined to end in a few years. The reckless collection of huge quantities of lichen compromised reproduction in a short time also because, as is known, the growth of the lichen thallus is always very slow.
The interest in the “roccella”, however, did not completely cease; in fact, in 1832, according to what Valery reports, the British subject William Sarderson Craig, employee of the Cassa Mackintosh in Glasgow, who later became the English consul in Cagliari, was present in La Maddalena, who had resumed the trade in lichen with profit. However, this activity lasted only a few years.
From Roccella tinctoria, as mentioned, various dyes and also litmus are obtained.
Litmus is a dye widely used in chemistry especially on paper supports (litmus papers); its wide use is due to the ability to change color according to the pH of the compound on which it is placed. It takes on a green color in case of neutral pH (pH equal to 7), a red color if found in an acid solution (pH less than 4.4) and a blue color if in contact with a basic solution (pH greater than 8). The use of this dye is of ancient tradition and this included the royal purple colors also known as orseille.
In Roccella tinctoria there is orcinol, a natural phenolic organic compound, present in many species of lichens.

Preparation Method –
Roccella tinctoria is a lichen that is collected in its natural state, dried and subsequently processed and mixed with other substances with various pHs to obtain colors and dyes of different shades and also added to some mordants.

Guido Bissanti

Sources
– Acta Plantarum – Flora of the Italian Regions.
– Wikipedia, the free encyclopedia.
– Useful Tropical Plants Database.
– Conti F., Abbate G., Alessandrini A., Blasi C. (ed.), 2005. An annotated checklist of the Italian vascular flora, Palombi Editore.
– Pignatti S., 1982. Flora of Italy, Edagricole, Bologna.
– Treben M., 2000. Health from the Lord’s Pharmacy, Advice and experiences with medicinal herbs, Ennsthaler Editore.

Warning: Pharmaceutical applications and alimurgical uses are indicated for informational purposes only, they do not represent in any way a medical prescription; therefore no responsibility is taken for their use for curative, aesthetic or food purposes.