Pinus sp.
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publication ID |
https://doi.org/ 10.37520/fi.2023.004 |
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persistent identifier |
https://treatment.plazi.org/id/4D2487A3-EF55-826F-FEF7-F97C6DF0FED9 |
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treatment provided by |
Felipe |
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scientific name |
Pinus sp. |
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Pinus sp. S6
Text-fig. 3t View Text-fig
M a t e r i a l. USNM PAL 619965, 622044, 622339,
623123, 776561.
L o c a l i t i e s. Disbrow Creek and Park.
D e s c r i p t i o n. Winged seed linear, at least 12.9– 21.4 mm long, 3.9–6.4 mm wide; seed body circular on proximal edge 1.8–2.1 mm wide; abmedial side of wing gradually or abruptly widens partly along seed body; striations undulatory and different widths.
R e m a r k s. Pinus subg. Pinus has seed bodies that are adnate to the wing and do not disarticulate ( Wolfe and Schorn 1990). This pine has an adnate wing, admedial edge longer than one cm and seed body smaller than 3 mm conforms to Wolfe and Schorn’s (1990) atypical Pinus 3 group.
Comments on Pinus
The Kishenehn pine seeds are summarized in Tab. 2. Pines are common and widespread amongst western North American Eocene and Oligocene localities. Erwin and Schorn (2005) recognized both hard and soft pines from the mid-Eocene Thunder Mountain flora of Idaho from Axelrod’s (1998) initial material: Pinus cf. crossii AXELROD (fascicle, Pinus subg. Strobus ), Pinus cf. sanjuanensis AXELROD (fascicle, Pinus subg. Strobus ) and Pinus cf. baileyi AXELROD (ovulate cone, Pinus subg. Pinus ). Ecologically, Pinus subg. Pinus tends to be more fire-adapted than Pinus subg. Strobus which is more tolerant to precipitation and temperature stresses ( Singh et al. 2021). Thus, either the Kishenehn Basin experienced both fire and drought and/ or severe cold temperatures or the basin is picking up a regional signature with Pinus subsp. Strobus coming in from the highlands. Incidentally, Pinus sp. Seed 6 likely would have been the more efficient disperser due to its small seed body and large wing ( Singh et al. 2021). Seeds weighing less than 90 mg are likely to be dispersed by the wind rather than animals, although secondary dispersal by animals may occur even in wind-dispersed pines ( Van der Wall 1992, Benkman 1995). It is also difficult to say if all six pine seed morphotypes represent six truly distinct species because pines often hybridize ( Critchfield 1975) and seed shape and size can vary depending on the part of the cone it developed in ( Erwin and Schorn 2005).
Summary of the conifers
Here, we recognize leaves and possible miniature seeds of Metasequoia ; a Juniperus leafy twig; four morphospecies of cupressaceous foliage that differ in leaf size, apex shape, leaf overlap patterns and branching patterns; one Abies seed; one Larix seed and a likely Larix cone; two species of Picea seeds; a Pinaceae leaf that cannot be assigned to genus; three Pinaceae cones that cannot be assigned to genera; a Pinus cone that cannot be identified to the subgenus level; a Pinus subg. Strobus cone; three species of Pinus subgenus Strobus seeds; a cone scale from Pinus subg. Pinus and three species of Pinus subg. Pinus seeds. The Dewey Mine florule of the mid-Eocene Thunder Mountain flora of Idaho, in comparison to the Kishenehn, represents a coniferous forest, unusual for its time considering most paleofloras of mid-Eocene age are broadleaf or mixed ( Axelrod 1998). The Kishenehn shares Cupressoideae foliage, Abies , Larix , Picea and Pinus (both Pinus subg. Strobus and Pinus subg. Pinus ) with the Thunder Mountain flora but lacks cf. Tsuga and cf. Sequoia ( Erwin and Schorn 2005) . The Kishenehn also has Metasequoia and Juniperus and contains a larger diversity in Cupressoideae foliage, which is not present in the Thunder Mountain flora. The presence of Metasequoia in the Kishenehn flora may be due to the fact that there was a paleolake at Kishenehn or that the Thunder Mountain flora, estimated to have been between 1,730 and 3,163 m by Axelrod (1998), may have been higher than Metasequoia ’s elevational tolerance ( Silba 1986).
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