Tepuianthus yapacanensis Maguire & Steyerm.
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Authority
Maguire, Bassett. 1978. The botany of the Guayana Highland--part XI. Mem. New York Bot. Gard. 32: 1-391.
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Family
Tepuianthaceae
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Scientific Name
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Description
Latin Diagnosis - Arbor 8-10-metralis, ramosa, ramulis ad apices dense tomentellis; foliis alternis vel oppositis petiolatis, laminis adscendentibus coriaceis supra nitidis glabris subtus dense sericeo-tomentosis stramineo- vel argenteo-luteis oblanceolatis apice rotundatis vel subtruncatis haud vel obsolete mucronatis basi acutis subacutis vel paullo subobtusis 3.0-4.5 cm longis 1.0-1.8 cm latis, costa media supra impressis subtus dense tomentosa pilis laxe adscendentibus vel fere patentibus obtecta conspicue elevata 0.7-1.0 mm lata, nervis lateralibus supra utroque latere 16-23 subelevatis 1-2 mm remotis subtus manifeste subelevatis 0.5-1.0 mm ante marginem anastomosantibus, venulis tertiariis supra obscuris subtus paullo manifes tis, petiolis 3-5 mm longis sericeo-tomenteUis; inflorescentia terminah vel subterminali, floribus paullo aggregatis, pedunculis 2-3 mm longis 3-4-floris, pedicellis 1.0-2.5 mm longis dense tomentosis; sepalis paullo inaequalibus exterioribus paullo latioribus ovato-oblongis vel late oblongis apice rotundatis vel obtusis 2.1-4.0 mm longis 1.5-2.5 mm latis extus sericeo-tomentellis pilis stramineo-argenteis obtectis intus glabris; petalis glabris obovatis 3.0-4.5 mm longis supra medium 1.5-2.0 mm latis unguiculatis 0.9-1.2 mm longis 0.1 mm latis; disco cum 5 glandulis late lunulatis discretis 0.5 mm longis 0.8-1.0 mm latis extus glabris; staminibus 12-16, 2-3-seriatis, antheris suborbiculari-ovalibus vel suborbiculari- oblongis, 0.3-0.8 mm longis, connectivo apice appendice minuto rotundato integro instructo, filamentis 1.5-3.0 mm longis; stylis 0.7-0.9 mm longis hirsutulis bifidis, ramulis 0.5 mm longis glabris; capsulis late ovato-suborbicularibus apicem versus gradatim angustatis 6 mm longis 5 mm latis extus dense sericeis pilis stramineo-griseis instructis, pericarpio 0.1-0.2 mm crasso intus glabro; seminibus atrobrunneis lanceolato-ovatis 4-6 mm longis supra medium in acumen 2 mm longum abrupte prolongatis, infra medium dilatatis 2.5 mm longis 2.5 mm latis glabris.
Distribution and Ecology - Distribution. Known only from the summit of Cerro Yapacana, in dwarf woodland, Amazonas, Venezuela (Map 1).
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Discussion
2. Tepuianthus yapacanensis Maguire & Steyermark, sp nov Type. Tree to 10 m high, flowers yellow, dominant cumbre tree, Cerro Yapacana, 1200 m alt, Territorio Federal Amazonas, Venezuela, 3 Jan 1951, Bassett Maguire, R. S. Cowan & John J. Wurdack 30683 (holotype NY). This species resembles Tepuianthus auyantepuiensis in the similar, loosely ascending to subspreading dense tomentum of the lower midrib of the leaf, the manifest lateral and tertiary venation of the lower leaf surface, and erect congested inflorescences on short peduncles and pedicels. It differs in the more numerous stamens, the obtuse to rounded apices of the calyx lobes, the greater number of lateral nerves of the leaf blades with non-mucronate apex, and in its habit as a well branched tree instead of that of a small subshrub with simple to sparsely branched stems.