Descripción de Aeonium urbicum ssp. boreale (Crassulaceae), una nueva subespecie de uno de los endemismos más representativos de Tenerife, islas Canarias

Abstract

Se describe e ilustra Aeonium urbicum ssp. boreale, un nuevo endemismo del extremo más septentrional de la isla de Tenerife. Los caracteres morfológicos de este nuevo taxón apoyan su descripción en el rango de subespecie. Se realiza el diagnóstico diferencial con las otras dos subespecies conocidas de A. urbicum, la ssp. urbicum de la vertiente Norte de Tenerife y la ssp. meridionale de la vertiente Sur y Suroeste de la isla. Se especifica su área de distribución, las características de su hábitat y su estado de conservación. Se incluye una tabla con los principales caracteres diagnósticos que diferencian a las tres subespecies de A. urbicum y una clave que facilita su identificación. Se deposita material tipo en los herbarios TFC de la Universidad de La Laguna y TFMC/ PV del Museo de Ciencias Naturales de Tenerife

Principles governing F1 hybridization in the genera Aeonium and Greenovia in La Gomera, Canary Islands

“…As mentioned above, all F1 hybrids in La Gomera always occurred when the geographical areas of distribution of the parents coincided (Arango 2023c). This was also the case for the 28 new hybrids studied in other islands of the archipelago (T, GC, P, H) (Arango 2015(Arango , 2016a(Arango , 2016b(Arango , 2017(Arango , 2019a(Arango , 2019b(Arango , 2019c(Arango , 2021a(Arango , 2021b(Arango , 2021c(Arango , 2023a.…”

“…Finally, each of the observational data collected in the field and the laboratory was assigned a score of 0, 1 or 2 (0: the parameter does not exist in the hybrids; 1: it exists but is not constant; 2: it exists and is shared by all natural hybrids), which allowed me to know the common characters in natural hybrids of Aeonium and Greenovia, and from this information I synthesized the principles governing the phenomenon of hybridization in La Gomera. Then, the analysis of the information stored in the database obtained from the observation of numerous natural hybrids in all the islands and my publications confirm that these principles can be extrapolated to the rest of the mountainous islands of the Canary Archipelago (Arango 2015(Arango , 2016a(Arango , 2016b(Arango , 2017(Arango , 2019a(Arango , 2019b(Arango , 2019c(Arango , 2021a(Arango , 2021b(Arango , 2021c(Arango , 2023a.…”

“…Analysis of the results of this work and those of Voggenreiter (1999), plus studies of numerous natural hybrids on other mountainous islands of the archipelago (GC, H, P, T), and methodical observations (Arango 2015(Arango , 2016a(Arango , 2016b(Arango , 2017(Arango , 2019a(Arango , 2019b(Arango , 2019c(Arango , 2021a(Arango , 2021b(Arango , 2021c(Arango , 2023a have provided essential information to better understand the natural history of F1 hybrids of the genera Aeonium and Greenovia, which I have synthesized into the following eight principles. The principles governing hybridization in the F1 generation in the genera Aeonium and Greenovia have been expressed as principles and not as laws because, in natural sciences, laws are universal, while principles are subject to biological evolution and changes in the natural environment and may have exceptions (Elgin 2003;Martínez & al.…”

“…They based this conclusion on their counts of taxa and hybrids in different islands resulting in Gran Canaria (more recently colonized by the genus) having a larger percent of hybrids than Tenerife (colonized earlier). Unfortunately, it appears that these authors finished their sampling in 2019 and have not considered all the novel taxa validly published of the genera Aeonium (two species, one subspecies, and ten nothospecies) and Greenovia (two species and one nothospecies) since then (Arango 2019a(Arango , 2019b(Arango , 2019c(Arango , 2019d(Arango , 2021a(Arango , 2023a(Arango , 2023b. When all the available data are considered, the numbers of hybrids known in every island are the following: Tenerife 30, La Palma 18, La Gomera 17, Gran Canaria nine and El Hierro six.…”