Fruticose lichens

Lichens Crustose lichens, foliose lichens, fruticose lichen... 

Crete, M., Lefebvre, M.A. and Zikovsky, L., Cadmium, lead, mercury and Cs in fruticose lichens of northern Quebec. Sci. Total Environ., 121 (1992) 217-230. 

Hall, R. S. B., Bomman, J. F., Bjom, L. O. 2002. UV-induced changes in pigment content and light penetration in the fruticose lichen Cladonia arbuscula ssp. mitis. J. Photochem. Photobiol B-Biol. 66 13-20. 

Figure 10. The toxic effect of Zn on foliose and fruticose lichens as observed near the river Spean, Spean-Bridge, Scotland, September, 1991.

Remedy for tickling in the throat (France). Used in Mauritius for a medicinal broth (may refer to all fruticose lichens) (de Candolle 1816 Lebail 1853)... 

Saenz MT, Garcia MD, Rowe JG (2006) Antimicrobial activity and phytochemical studies of some lichens from south of Spain. Eitoterapia 77 156-159 Santiago KA, Borricano JN, Canal JN et al (2010) Antibacterial activities of fruticose lichens collected from selected sites in Luzon Island, Philippines. Philipp Sci Lett 3 18-28 Santos PS, Lat B, Palo M (1964) The antibiotic activities of some Philippine lichens. Philipp J Sci 93 325-335... 

In some fruticose lichens, such as Usnea which has a radial arrangement of the tissues, a central axial strand can be distinguished internal to the medulla (Fig. 46). The structure of the central axis is dense and consists of paraplectenchymatous or prosoplectenchymatous tissue giving considerable tensile or skeletal strength to the thallus. In other genera, i.e., Alectoria, Cladonia, and Ramalina, the central axis is absent. Its place can be taken by a central hollow or by gelatinous or spongy tissues. In Letharia a central cord is formed by fusion of several smaller strands (Fig. 29). 

Intermediate Forms between Foliose and Fruticose Lichens... 

The lobes of fruticose lichens are strap-shaped or threadlike with a radial or dorsiventral thallus. Ramalina (Fig. 70) and Roccella (Fig. 79) are good examples of strap-shaped, radial thalli, while Usnea (Fig. 75) consists of thin strands up to 5 m long. Evernia and Pseudevernia have strap-shaped, dorsiventral thalli. 

The habit of hairlike lichens, with their threadlike thalli, resembles that of fruticose lichens. These lichens, however, are much smaller and usually not more than a few millimeters high. In contrast to most lichens, the habit is principally determined by the phycobiont. Filamentous algae, belonging to the Chlorophyceae or the Cyanophyceae, are more or less closely ensheathed by hyphae of the mycobionts (Figs. 23-25). 

Lichens have unique vegetative structures that are found frequently in foliose and fruticose lichens and sometimes in crustose forms. Some of these structures serve as vegetative diaspores for the dispersal of the lichen and may have special physiological functions. All vegetative structures are of vital importance in taxonomic studies of lichen speciation. 

Pseudocyphellae are formed on the upper and lower surface of several foliose and fruticose lichens. In Pseudocyphellaria they form irregular warts. The openings are filled by a network of short cells (Fig. 89). In very old and abnormally large pseudocyphellae algal cells may be deposited between the loose hyphae. These pseudocyphellae resemble soralia but the similarity is misleading as no soredia are produced. 

The pseudocyphellae of the fruticose lichen Cornicularia divergens (Fig. 84) are either shallow depressions in the cortex or they form pores that penetrate to the medulla (Fig. 94). The pseudocyphellae on the upper side of Cetrelia cetrarioides show a similar development (Fig. 95). 

Development of Soralia. The formation of a soralium may be initiated by the medullary hyphae. In heteromerous, foliose, or fruticose lichens... 

Since the different methods of vegetative dispersal have very unequal taxonomic value, I will briefly discuss special features below. This does not include thallus growth with subsequent division of thallus parts by dying away of the center or dispersion of branched fruticose lichens by dying off at the base. 

The role of rhizines and haptera (suckerlike sheaths) in the attachment of the thalli of foliose and fruticose lichens to the substrate was described by Smith (1921) and by Poelt and Baumgartner (1964). Rhizines are abun-... 

The study of the lichen s ability to use water vapor from a nonsaturated atmosphere is of particular interest. The main part of the water in a vapor state absorbed by lichens enters the thallus only at a relative humidity that is above 90%. For foliose and fruticose lichens placed in an atmosphere with a relative humidity of 95%, Butin (1954) and Ried (1960b) found that the maximum amounts of water absorbed by the thalli were 30-50% of the water content of thalli fully saturated with liquid water. These findings were confirmed by our experiments (Fig. l)(Blum, 1965). The absorption of water vapor as well as liquid water to a certain extent depends on anatomical and morphological peculiarities of lichens. That is why various species have marked differences in the rate and amount of water vapor absorbed from equal relative atmospheric humidities. These differences become more pronounced with the increase of water vapor content in the atmosphere. 

Certain tissues of fruticose lichens, such as Ramalina Usnea, and Evernia, often extend deep into the corky bark tissue by growing between the periderm layers with hapteral wedgelike action. Studies of Rawa/ma species by Porter (1917) showed that these lichens gain entrance to the inner bark... 

Another method of direct measurement can be used for certain fruticose lichens that are not attached to the substratum. Karenlampi (1971), for example, placed loose colonies of various reindeer mosses (Cladonia) in boxes on the forest floor. Every 1-4 weeks these were removed from the boxes, air-dried, weighed, and returned to the boxes without damage. A rather similar technique was tried by Miller (1966) for foliose lichens but with less success because of breaking up of the thalli. 

Karenlampi, L. (1971). Studies on the relative growth rate of some fruticose lichens. Rep. Kevo Subarctic Res. Sta. 7, 33-39. 

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