Magnolia guatemalensis Donn.Sm.
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Authority
Vázquez García, J. Antonio. 1994. Magnolia (Magnoliaceae) in Mexico and Central America: A Synopsis. Brittonia. 46 (1): 1-23.
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Family
Magnoliaceae
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Scientific Name
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Discussion
Magnolia guatemalensis Donn. Sm., Bot. Gaz. (Crawfordsville) 47: 253. 1909. TYPE: GUATE- MALA. Alta Verapaz: "In palude profunda prope Tactic," 1550 m, Mar 1908 (fl), H. von Tuerck- heim 11 2165 (HOLOTYPE: US!).
Magnolia guatemalensis is a rather polymorphic species in that the leaves occa- sionally lack pubescence on the lower sur- face and are variable in size and shape as are the petals. The following variations are observed in the specimens examined: 1) Characteristic populations of M. guatemalensis are represented by a large series of Steyermark collections from Tactic, Alta Verapaz, Guatemala (the type locality) with leaves broadly obovate to almost round. Additional collections from Alta Verapaz are similar. 2) A collection from Sierra de Las Minas, Zacapa (Steyermark 42540, F), with very large leaves (32 x 14 cm), was treated by Standley and Steyermark (1946) as doubtfully referable to M. guatemalensis. Comparing this specimen and many others from Zacapa with a specimen with relatively small leaves (16 x 8 cm) from the type locality (Standley 92385, F) and a second with intermediate-sized leaves (23 x 1 1 cm) from Santa Rosa (Cook & Doyle 259, US) makes it clear that all represent a size gradient, having in common glabrous leaves, wax at the base of the petiole, and propor- tionally large, stiff, asperous, dark brown to black stipules. These specimens, therefore, are cited here under M. guatemalensis. 3) In El Salvador, several specimens from a single locality, Cerro de Monte Cristo Na- tional Park, have broadly elliptic to oblong- elliptic, mostly very small leaves, possibly related to the low humidity characteristic of the less mesic slopes facing the Pacific Ocean. Two specimens from the same locality, however, have larger elliptic leaves, resem- bling those of the geographically closest population at Intibuca, Honduras. 4) Pop- ulations from Honduras, mainly from three cordilleras (Opalaca, Montecillos, and Gua- jiquiro), tend to have narrower, oblong-el- liptic leaves (19 x 5-7 cm) and were iden- tified by A. R. Molina as M. hondurensis A. R. Molina. I have not however, observed any significant differences between these populations and M. guatemalensis. In fact, M. hondurensis and M. guatemalensis share many features, e.g., fruit structure, number of carpels, shape of floral parts, and pubes- cence of abaxial leaf surface, flower buds, and peduncle. Nevertheless, the lack of ad- equate flowering and fruiting specimens for most populations prevents a detailed cir- cumscription of this variability. Thus, M. hondurensis differs from M. guatemalensis in only a few characters, namely narrower leaves and petals. Because these characters are correlated with geography, the two dis- tributions being allopatric, it is appropriate to consider M. hondurensis a subspecies of M. guatemalensis.