Pinus tecunumanii Eguiluz & J.P.Perry

  • Authority

    Farjon, Aljos K. & Styles, Brian T. 1997. Pinus (Pinaceae). Fl. Neotrop. Monogr. 75: 1-291. (Published by NYBG Press)

  • Family

    Pinaceae

  • Scientific Name

    Pinus tecunumanii Eguiluz & J.P.Perry

  • Type

    Type. Guatemala. Baja Verapaz: San Jeronimo,  collected at finca INAFOR, 60 m (NE) down from the tower of GUATEL, Eguiluz 2 (holotype, GH).

  • Synonyms

    Pinus patula subsp. tecunumanii (F.Schwerdtf. ex Eguiluz & J.P.Perry) Styles, Pinus oocarpa var. ochoterenae Martínez

  • Description

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    Species Description - Tree, usually tall, height to 50-55 m, dbh to 120-140 cm. Trunk monopodial, erect, straight, terete, bole of large trees usually clear of branches for 2030 m. Bark on lower part of the trunk thick (ca. 5 cm), grey-brown, above 3-4 m thinning, reddish brown, on young trees and branches thin, exfoliating in thin flakes, light reddish brown. Branches long, slender, spreading or slightly ascending, the higher-order branches flexible but not pendulous. Shoots rough, with persistent bases of decurrent pulvini, reddish brown, often glaucous. Cataphylls spreading or recurved after the leaves have fallen, subulate, erose-ciliate at margins, scarious, brown, weathering to blackish grey. Vegetative buds oval-oblong to cylindrical, the terminal bud 15-20 mm long, the laterals smaller, not resinous; the scales spreading, subulate, ciliate at margins. Fascicle sheaths initially long, up to 25 mm, (light) orange-brown, the imbricate scales with ciliate, whitish margins, in mature fascicles reduced to 12-18 mm, persistent, tight, weather-ing slowly, grey-brown, sometimes blackish brown. Leaves in fascicles of 4(3-5), in lax, spreading tufts, persisting 2-3 years, drooping but not pendent, (14-) 16-18(-25) cm X 0.7-1 (-1.3) mm, serrulate at margins, acute, bright green. Stomata on all faces of the leaves, in (3-)5-8 lines on the convex abaxial face and in 2-5 lines on each adaxial face. Leaf anatomy: Triangular to transverse-triangular in cross section; hypodermis with a double layer of cells except in marginal areas where it is thicker; resin ducts (2-)3-4(-5), medial, occasionally 1 internal, or septal by connection with additional hypodermal cells; stele transverse-obovate in cross section; cells of the endo-dermis thin-walled or rarely slightly thickened; vascular bundles 2, the xylem strands connate. Pollen cones crowded near the proximal end of a new shoot, spreading, subtended by scarious bracts, ovoid-oblong to cylindrical, 15-20 X 5-6 mm when shedding pollen, yellowish, turning yellowish brown. Seed cones subterminal, in whorls of 2-4, rarely solitary, on (15-)20-25 mm long peduncles, semi-serotinous, persisting 1-3 years after shedding seeds, falling with the peduncles. Immature cones broadly ovoid, with acutish apex, on long, recurved peduncles with persistent cataphylls, purplish, soon light brown, maturing in two seasons (or equivalent time). Mature cones ovoid to broadly ovoid, with acutish apex when closed, nearly symmetrical or asymmetrical, with a rounded base in open cones, (3.5-)4-7(-7.5) X (3-)3.5-6 cm when open. Seed scales ca. 100-140, parting usually within 1-2 years after maturity, oblong, straight or slightly curved, the proximal scales remaining connate, purplish brown to reddish brown, with light brown marks of seed wings adaxially. Apophysis raised, transversely keeled, on proximal scales more or less gibbous, rhombic to obtrullate in outline, or with a rounded, but crenate, upper margin, striate, dull light brown or slightly lustrous. Umbo dorsal, flat or slightly raised, 3-5 mm wide, with a minute, deciduous prickle, grey. Seeds obliquely ovoid, slightly flattened, 4-7 X 2-4 mm, dark grey-brown, with blackish dots, or blackish grey. Seed wings articulate, effective, held to the seed by two thin claws, obliquely ovate, 10-13 X 4-8 mm, grey-brown. Cotyledons (4-)5-6(-7), of equal length.

  • Discussion

    Uses. While occasionally still abundant and of very tall stature, this pine is now usually scattered in small, disjunct populations and has been depleted by overexploitation and forest clearing, especially at lower elevations, to such an extent that many of these populations are now vulnerable to extinction (Dvorak & Donahue, 1992). This taxon has received considerable interest from foresters as a species for potential plantation forestry to be introduced in tropical countries. A comprehensive collection of seed and specimens was carried out by the Oxford Forestry Institute (OFI), as well as by other organizations, throughout its entire range.

    Schwerdtfeger (1953), as explained by Styles (1984), studied the pines of Guatemala in connection with a pathological outbreak of a bark beetle and carne to the conclusion that a species new to science occurred there. He named it “Pinus tecumumamii," misspelling the name while commemorating the 16th-century Indian leader Tecun Umán, but his description is invalid under the Code (Art. 36.1, see Greuter et al., 1994). Eguiluz and Perry (1983) later described the species as new (no type specimen had been indicated by Schwerdtfeger), using the correct orthography and designating a type specimen.

    Martinez (1940) described a new variety of Pinus oocarpa, var. ochoterenae, from Chiapas, Mexico. In the protologue, he did not designate a type specimen but cited collections he had seen from three locations: Ocosingo, Coapilla, and Las Casas [San Cristóbal de las Casas). On some of the labels he wrote “var. nov.” and “tipo.” Martinez. 3461 is here designated as the lectotype. Martinez enumerated five characters that differentiate var. ochoterenae from P. oocarpa. The first character state-leaves in fascicles of (3-)4-5 (mostly 4 in Martinez 3461)- is intermediate between P oocarpa and P. patula. The medial resin ducts described by Martinez are a state rarely encountered in P oocarpa but are the rule in P. patula. The cones of Martinez’s taxon have characters of both P. oocarpa and P. patula but are, on the whole, less persistent and serotinous than either of these. Field studies carried out by Styles (1976) in the highlands of Chiapas pointed to further differences with “typical” P. oocarpa, which is sympatric in this region.

    In their paper describing P. tecunumanii, Eguiluz and Perry (1983) present an evaluation of comparative characters of this species and P. oocarpa var. ochoterenae, using morphological as well as chemical (terpenoids) characters or traits. These show slightly greater mean size for most character states in P. oocarpa var. ochoterenae. However, several of them indicated as highly significant-the sequence cone size, seed scale size, seed wing size-are, in fact, fully interdependent morphologically. This leaves only the size of the cones to be considered, which, singularly, being much more variable than their limited samples suggest, taxonomically is not a very informative character.

    Meanwhile, Barnes and Styles (1983), Styles and Hughes (1983), and Styles (1984) had concluded that P. tecunumanii should be classified as a subspecies of P. patula. In the opinion of the authors, the application of statistical methods supported the classification of this taxon as distinct from P. oocarpa. However, a complex sequence of calculations involving continuous character states is necessary to arrive (by their method) at identification, whereby a possibility of error remains (McCarter & Birks, 1985; Birks & Barnes, 1985). They found such a high level of “continuities in the variation patterns'’ within the two taxa that “orthodox taxonomic methods . . . are largely unsatisfactory.” The second study looked primarily at growth performances of provenances (in part sampled from those used in the first study) in plantation trials, which indicated genetically based differences between them. It is difficult, however, to determine the significance of these outcomes for species delimitation, given the great geographical and ecological ranges of the taxa involved.

    Eguiluz (1986) undertook a comparative phenetic and biochemical study to determine the taxonomic relationships of Pinus tecunumanii. The two closest related taxa, P. oocarpa var. ochoterenae and P. patula var. longipedunculata, as well as P. maximinoi (but not P. oocarpa var. oocarpa or P. patula var. patula) were chosen for this evaluation of relationships. Apart from the apparent undersampling (15 trees from one locality for each of the two varieties against more than 100 trees from five localities in Guatemala for P. tecunumanii), there is the familiar misunderstanding among forest geneticists turning to phenetics that a t-test performed on the means of morphological measurements with a “high significance level” is proof of taxonomic distinction at species level. In reality, the character states found in the analysis are not only quite similar (e.g., a mean leaf length of 17.5 cm and 19.4 cm found for P. tecunumanii resp. P. oocarpa var. ochoterenae) but also of a continuous nature, with overlapping states in many trees. Furthermore, of the morphological characters used, several are interdependent, such as length of seed scale and seed wing, and cannot be “added up” to argue differences or similarities. The outcome of the cluster analysis, which placed P. tecunumanii at a greater “taxonomic distance” from the two varieties of P. oocarpa and P. patula than these are from each other, is for these reasons not conclusive.

    In a detailed study of this taxon, Styles and McCarter (1988) clearly point out the difficulties with the identification, especially in distinguishing it from P. oocarpa “at middle elevations (900-1600 m) on sites where the two species occur together.” Yet they maintain Styles’s classification of the taxon as P. patula subsp, tecunumanii, but agree that its status is likely to remain controversial. Indeed, Squillace and Perry (1992), in a paper using mainly terpene compounds as characters, maintained specific status for this taxon. They also maintained P. oocarpa var. ochoterenae, which in Perry’s (1991: 188-189) morphological comparison appeared to score 7 times toward P. patula and only 3 times toward P. oocarpa.

    Finally, a molecular approach to the problem using RAPD markers on bulked DNA samples of these pines (Grattapiglia et al., 1992) pointed at an “unexpected distinctiveness between P. patula and P. tecunumanii." Until more, and perhaps more informative, DNA characters have been found, the debate is likely to circle around the interpretation of old data. Introgression, assumed to play a role especially at lower altitudes, with P. oocarpa (Dvorak & Donahue, 1992) may complicate even this more direct genetic approach. For these reasons, it seems prudent to recognize this taxon in its original rank of species until its relationship with P. oocarpa and P. patula and their respective varieties has been clarified, if it ever will be.

    Distribution and Ecology: Essentially Mesoamerican, distributed throughout low- to high-montane regions of Chiapas (Mexico), Guatemala, Belize, Honduras, El Salvador, and Nicaragua. Pinus oocarpa var. ochoterenae (here treated as a synonym) was reported from Nicaragua into Oaxaca; it was also said to occur in SE Guerrero (Perry. 1991). The altitudinal range of this species is considerable: (300-) 550-2500(-2900) m. In Belize it is found at 300760 m. It is a major constituent of more or less open to closed-canopy pine and pine-oak forests in climatic zones that receive annual rainfall of at least 1000 mm, and up to 2500-3000 mm in some places. The dry season is usually long, lasting from November to May, so that at lower to middle altitudes fires are an integral phenomenon in the ecosystem (the frequency, however, having been greatly accelerated by humans). Here, open pine stands with grasses, Pteridium aquilinum, Rubus, Calliandra, and Leucaena are predominant as long as the disturbances do not lead to further degradation. In less disturbed areas, mostly at higher altitudes, P. tecunumanii is often associated with other pines, such as P. oocarpa, P. maxi mino i, P. pseudostrobus, and, at the more mesic sites, P ayacahuite and P. strobus var. chiapensis. Abies guatemalensis and Cupressus lusitanica are other conifers on these high mountain ridges. On the Atlantic slopes in Chiapas, a mixed angiosperm forest with Liquidambar, Magnolia, Clethra, Carpinus, Symplocos, Quercus, and many other species predominates; and Pinus tecunumanii and other pines occur either on poorer sites or at an earlier stage in a sere leading back to dominance of broad-leaved trees.

    Phenology: Pollen dispersal occurs in February-March in the highlands of Guatemala and Chiapas, and may be earlier at lower altitudes in tropical regions.

  • Distribution

    Mexico North America| Chiapas Mexico North America| Oaxaca Mexico North America| Guatemala Central America| Baja Verapaz Guatemala Central America| Chiquimula Guatemala Central America| El Progreso Guatemala Central America| Quiché Guatemala Central America| Guatemala Guatemala Central America| Huehuetenango Guatemala Central America| Totonicapán Guatemala Central America| Zacapa Guatemala Central America| Belize Central America| Cayo Belize Central America| Honduras Central America| Comayagua Honduras Central America| Cortés Honduras Central America| La Paz Honduras Central America| Lempira Honduras Central America| Olancho Honduras Central America| Chalatenango El Salvador Central America| Santa Ana El Salvador Central America| Nicaragua Central America| Estelí Nicaragua Central America| Jinotega Nicaragua Central America| Matagalpa Nicaragua Central America| Nueva Segovia Nicaragua Central America|