Niebla homaleoides

©The World Botanical Associates Web Page
Prepared by Richard W. Spjut
April 2003, Oct. 2005, Sep 2012

Niebla and Vermilacinia (Ramalinaceae) from California and Baja California.  
Spjut, R.W., 1996. ISSN 0833-1475, 208 pp.  
Sida, Botanical Miscellany: 14. Botanical Research Institute of Texas, Inc.

 

 

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El Marrón, ridge S of Punta
Negra, Spjut 9964B, May 1986

homaleoides-11534.jpg (114819 bytes)

Punta Cono, Spjut & Marin 11534, Apr 1990

 

homaleoides-9958.jpg (349515 bytes)

El Marrón, ridge S of Punta
Negra, Spjut 9958, May 1986

El Marrón, ridge S of Punta Negra, Spjut 9963B, May 1986

Niebla sp. undescribed, aff. N. homaleoides, N. flabellata.

Arroyo Sauces, between Punta Canoas and Punta Blanco, W of Rancho San José
Spjut & Marin 11431B,
Apr 1990

Geographical Distribution

      Niebla homaleoides is a rare lichen known only from three locations in Baja California; two are from ridges south of Punta Negra, and a third is from a rocky peninsula near sea level at Punta Cono.   The type locality is a large rock pile on a ridge where collected in close association with N. josecuervoi and N. infundibula.  An attempt was made in the field to sort these (May 1986); however, it was not until later that it was concluded that they could only be distinguished by their lichen substances as a result of using thin-layer chromatography (TLC). 

     Their close resemblance to each other is clearly evident in the image above that includes the TLC graphic.  They are similar in overall size and branching, have the same sublinear branch shape, have the same glossy and color cortical features, have prominent large and abundant pycnidia on upper branches, all lack reticulate ridging, and all show similar development in branchlets including shape and size—somewhat elliptical and flattened—rarely seen in other species with cylindrical branches.  This seems more than coincidental considering the wide range of morphological variation in Niebla observed elsewhere on the ridge and generally in Baja California (e.g., see associated species with reference to collection numbers under N. caespitosa). 

     For example, Niebla josecuervoi, which has secondary metabolites of salazinic acid, occasionally with a scabrosin derivative and consalazinic acid, usually has a reticulately ridged cortex, evident in all 12 other specimens shown on the WBA page. Did a spermatium from N. homaleoides contribute to a spore progeny thallus of N. josecuervoi originating from an apothecium of N. josecuervoi Niebla infundibula, another relatively rare lichen known from this location, shows similar hybrid characteristics. Did a spermatium from N. homaleoides contribute to a spore progeny thallus of N. infundibula originating from an apothecium of N. infundibula?   Other specimens of N. homaleoides from the same ridge and from Punta Cono have more flattened blades, which may be characteristic of its true form.  In the higher plant world such blending of character traits among three species would be viewed as evidence of introgression.  Perhaps, secondary chemical substances in Niebla are allelopathic towards  related species (Molnára & Farkas 2010) in which case N. homaleoides lacking in secondary metabolites is less competitive and more freely hybridizes?

      Notwithstanding, Niebla homaleoides is identified by its lack of key lichen substances.  Its chemical relationships are clearly allied to the salazinic-acid species subgroup by the presence of an unidentified pigment thought to be a scabrosin derivative, and further linked to the Depsidone Species Group of Niebla by the absence of triterpenes (Spjut 1996).  This pigment has been found in N. effusa, N. flabellata, N. marinii, and N. josecuervoi.    

       Bowler and Marsh (2004) failed to account for the chemical relationships when they erroneously placed Niebla homaleoides in synonymy with N. homalea (divaricatic acid); i.e. in following their taxonomic scheme they should have lumped it with N. josecuervoi.  Just because N. homaleoides does not react to p-phenylenediamine (PD-) does not mean that it is related to other species that are PD-.   The resemblance to N. homalea is seen in the blade morphology in the one specimen from Punta Cono.  The relationship of N. homaleoides to the depsidone group is also evident by the pycnidia that develop at the tips of the spine-like branchlets, some of which are shortly bifurcate.

      Chemically deficient thalli in the genus Niebla occur at one other location, Arroyo Sauces for which a specimen is shown above.  It  differs from N. homaleoides in having more flattened lacerated branches as in N. flabellata. This lacerated branch form was also collected at Punta Cono.  Their similar morphology at two disjunct locations would seem to represent another acid-deficient species, referred to as Niebla sp. undescribed, shown above for the one from Arroyo Sauces. 

Additional Reference Cited:

Molnára, K.  and E. Farkas. 2010. Current results on biological activities of lichen secondary metabolites: A review. Z. Naturforsch. 65 c, 157 – 173.