Magnolia lacandonica A. Vázquez, Pérez-Farrera & Mart.

Vázquez-García, J. Antonio, Tribouillier-Navas, Erick, Archila, Fredy, Aguilar, Rudy Eduardo & Shalisko, Viacheslav, 2022, Two new species of Magnolia (Magnoliaceae) from Alta Verapaz and Quiché, Guatemala, Phytotaxa 559 (1), pp. 35-44 : 40-41

Magnolia lacandonica A. Vázquez, Pérez-Farrera & Mart. -Camilo in Vázquez-García et al. (2013c: 31) .

Type:— MEXICO. Chiapas: Municipality Marqués de Comillas , Boca Chajul, 0.4 km al NO de la casa del Sr. Manuel Lombera, selva alta perennifolia, 150 m elevation, 16°7’18.37”N, 90°55’32.44”W, 8 May 2012 (fl. bud & fl.), Vázquez-García et al. 9341 (holotype: IBUG!, isotypes: HEM!, MEXU!) .

Magnolia lacandonica belongs to M. sect. Talauma and has been previously confirmed only from populations in the lowland tropical rainforest of Chiapas, México. Based on morphology and supported by shared climate (similar rainfall and temperature regimes) and vegetation type, M. lacandonica is here confirmed from Alta Verapaz, Guatemala ( Fig. 4 ) (further details in Aguilar 2022).

Voucher specimen for this record. GUATEMALA. Alta Verapaz: Cobán, aldea El Triunfo Nueve Cerros, 184 m a.s.l, 16°02”45” N , 90°44”43.5” O, 30 August 2021 Mendoza et al. 275 ( BIGU!).

Notes:— Our present and recent discoveries of Magnoliaceae in Guatemala support the hypothesis that our current knowledge of global tree diversity remains incomplete. Botanical inventories are geospatially biased to certain areas, where the sampling coverage includes abundant and rare species, but vast areas outside of such preferred remain poorly sampled ( Ter Steege et al. 2016). The challenge of describing this unknown tree diversity is great because most undiscovered species are likely to be narrow endemics with small population sizes. Because they are rare plants, they are potentially threatened by anthropogenic factors ( Enquist et al. 2019, Gatti et al. 2022).

The case of Magnolia in Guatemala demonstrates that the appreciation of having a relatively good knowledge of Guatemalan flora may be misleading because only 11% of Magnolia richness was included in Standley & Steyermark (1946). Even in the case of tree species that are less prone to escape a botanist’s attention, the current knowledge is far from sufficient. The search for rare and endemic tree species is of special importance in the case of the flora of Guatemala because it is a region with one of the highest levels of tree endemism among mainland regions worldwide, ranked in tenth position (Sandell et al. 2019). The extremely diverse flora of Guatemala with 7132 species recognised in the published flora ( Standley & Steyermark 1946, Steyermark 1950) was estimated to have about 8000 vascular plant species ( Gentry 1978) and looked to be fairly well collected and studied when compared with some other underexplored Neotropical areas.

The study presented here allows us to formulate the following conclusions about Guatemalan Magnoliaceae :

1. Guatemala, with 18 species of Magnolia , is fourth among Neotropical countries, surpassed by Colombia (40 spp.), México (36 spp.) and Ecuador (23 spp.) ( Vázquez-García et al. 2014).

2. These findings add to the high endemism of Magnoliaceae in Guatemala (10 out 18 species) increasing from 53 to 56% ( Vázquez-García et al. 2021b). Endemism in Alta Verapaz increased from three to four species of Magnolia , whereas Quiché increased from two to three species ( Vázquez-García et al. 2021b).

3. Simultaneously with the exploration of Magnolia diversity in Guatemala, progress has been made in ex-situ and in-situ conservation. Plant nurseries have been created to produce endangered Magnolia species for reforestation ( Vázquez-García et al. 2013 a, Tribouillier-Navas et al. 2019, Vázquez-García et al. 2021b).

4. The new species here discovered are already propagated and maintained as ex-situ collections in the recently established National Magnoliarium of Guatemala, Coban, Dept. Alta Verapaz, at the beginning of 2022 (Archilarum 2021, Magnoliarum, Facebook: https://fb.watch/ceLstJOJ86/).

Figures

FIGURE 4. Distribution of Magnolia quichensis, M. weerakitana and other Magnolia species from the centre of Magnolia endemism in the Guatemalan north-west-arc.