Heteroflorum M. Sousa, Novon 15: 213. 2005.
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publication ID |
https://dx.doi.org/10.3897/phytokeys.240.101716 |
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persistent identifier |
https://treatment.plazi.org/id/AB6F7F0D-D206-0431-91BF-1021854AF747 |
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treatment provided by |
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scientific name |
Heteroflorum M. Sousa, Novon 15: 213. 2005. |
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Heteroflorum M. Sousa, Novon 15: 213. 2005. View in CoL
Figs 67 View Figure 67 , 70 View Figure 70 , 75 View Figure 75
Type.
Heteroflorum sclerocarpum M. Sousa
Description.
Unarmed small trees to 15 m, forked near the base, forming a wide spreading umbrella crown (Fig. 67J View Figure 67 ), the trunk with horizontal lines of conical corky protuberances, these not or barely spinescent, otherwise bark smooth pale to mid metallic grey (Fig. 67K View Figure 67 ). Stipules acicular to setiform, caducous. Leaves bipinnate, petiole eglandular, canaliculate, sulcate with (2) 4-7 pairs of pinnae, 10-14 pairs of alternate leaflets per pinna, these elliptic-oblong. Inflorescences more or less erect axillary racemes, flowers subtended by jointed pedicels, bracts persistent. Flowers unisexual by reduction of the androecium or gynoecium, dioecious, a well-developed hypanthium at the base; sepals 5, free; petals 5, homomorphic elliptic to obovate, yellow, lacking a claw; stamens 10, free, exserted beyond the corolla, inserted at the apex of the hypanthium; pollen not studied; ovary sessile, 9-13 ovules, style tubular, widened at apex, stigma circular, broad, flat or slightly concave. Fruits indehiscent, cylindrical, hard, weakly woody, the mesocarp thickened and fibrous, the valves smooth, glabrous, pale orange-brown when ripe (Fig. 70K, M View Figure 70 ), with fibrous-spongy septae between the seeds forming marked seed cavities (Fig. 70L View Figure 70 ). Seeds discoid to subspherical, integument hard, hilum apical.
Chromosome number.
Unknown.
Included species and geographic distribution.
Monospecific. A narrowly restricted endemic of southern Mexico, disjunctly distributed close to the Pacific coast in the lower reaches of the Río Balsas watershed around El Infiernillo ( Michoacán and Guerrero) and in coastal Oaxaca (Fig. 75 View Figure 75 ). Heteroflorum sclerocarpum and hence the genus as a whole, is categorised as Endangered (Machuca- Machuca et al. 2021).
Ecology.
Confined to seasonally dry tropical forest, occasionally forming dominant stands ( Urrea-Galeano et al. 2018). Trees are strongly deciduous, flowering when leafless or as new leaves flush. Fruits indehiscent and reported to be consumed by terrestrial mammals facilitating release of the seeds and accelerating germination ( Urrea-Galeano et al. 2018), and potentially endozoochorous seed dispersal. Flowers pollinated by large Xylocopa bees.
Etymology.
The name Heteroflorum is derived from hetero - (Greek = different, uneven) and - florum (plural of flos; Latin = flower) in reference to the different sized functionally male and female flower forms associated with dioecy.
Human uses.
Unknown.
Notes.
Heteroflorum is robustly supported as sister to a second monospecific Mexican endemic genus, Conzattia (Fig. 66 View Figure 66 ; Haston et al. 2005; Ringelberg et al. 2022). These two genera share similar tree growth habit and bark (Fig. 67J-M View Figure 67 ), and flowers, but have completely different fruits (Fig. 70K-M View Figure 70 ).
Taxonomic references.
Sousa (2005) with illustration.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.