Monographs Details: Mouriri dimorphandra Morley
Authority: Morley, Thomas. 1976. Melastomataceae tribe Memecyleae. Fl. Neotrop. Monogr. 15: 1-295. (Published by NYBG Press)
Description:Latin Diagnosis - Arbor usque 25 m alta trunco 35 cm diametro, praeter inflorescentiam glabra; ramuli juvenes tereto-quadrangulares vel canaliculata interdum peranguste 4-alati. Petioli 4.0-8.0 mm longi; laminae 7.0-16.0 cm longae, 3.6-7.5 cm latae, ellipticae usque ovato- vel oblongo-ellipticae, ápice abrupte breviacuminato vel acuto, basi rotundata usque late acuta et abrupte attenuata in petiolo; superficies costae mediae plana vel canaliculata in quoque later, pagina inferior prominens, peranguste 2-alata; nervi laterales manifesti in sicco. Cryptae stomatatae 45-115 µ diametris, 35-55 µ altae, 40-70 in mm2; sclerides terminales foliariae stellatae. Inflorescentiae ad nodos ramulorum aphyllorum usque ad 6.0 mm crassorum, 1-4 in quoque later ad nodos, singulae 1-15-florae, 5.0-27.0 mm longae ad bases pedicellorum secus axes cum inter-nodiis 1-4, ramosae, bracteis ovato-triangularibus 0.8-1.3 mm longis; pedicelli 6.0-9.0 mm longi. Superficies axium inflorescentiae, pedicellorum, et plerumque basis ovarii puberulae. Calyx ovarium inferior includens 3.2-4.3 mm longus in sicco, ca 3.5-4.8 mm in vivo; hypanthium liberum nullum; lobi calycis 0.4-0.8 mm longi, 2.5-3.2 mm lati, 1.0-1.4 mm longi ab staminibus, late rotundati vel triangulares et interdum apiculati. Petala lutea vel purpurea, 7.0-12.3 mm longa, 3.5-6.0 mm lata, ovato-elliptica, elliptica, vel raro obovato-elliptica, apice acuto, basi truncata. Filamenta 3.4-5.5 mm longa; an-therae luteae, dimorphae: antherae lobos calycis oppositae 3.4-4.0 mm longae, thecis 2.9-3.0 mm longis ad basim geniculatis; antherae petalas oppositae 3.1-3.6 mm longae, thecis 2.4-2.8 mm longis rectis; thecae poris apicalibus dehiscentes; glandula 0.4-0.6 mm longa. Ovarium 5-loculare; placentae basilares in quoque loculo, ovula 7-16 undique circum quamque placentam genita, 42-71 singulo ovario; stylus 11.0-13.0 mm longus. Fructus depresso-globosus, calyce coronatus, ca 7.0-8.5 mm altus calyce excluso x ca 9-11 mm crassus in sicco, probabiliter 8.5-10.0 mm altus x 11-13 mm crassus in vivo, 2-5 spermus. Semina fusca, 5.9-7.0 mm longa, 4.8-6.0 mm lata, 4.0-5.0 mm crassa; hilum basale, rotundum vel leviter cordiforme, 26-3.2 mm longum, 2.0-2.4 mm latum.

Description - The epithet refers to the two forms of anthers. Midrib xylem tubular; stomatal crypts Type III, averaging in a leaf ca 62-85 in diam, 42-45 µ high, 45-55 per sq mm (extremes given above); upper epidermis one cell thick, all cells with mucilaginous walls; hypodermis none, although sometimes simulated by the upper layer of palisade cells which may be short and wider than high.; free stone cells of the midrib abundant to its tip in the pith, scattered sparingly for most of its length in the cortex; terminal sclereids stellate, the central body 1-2 times as long as wide, usually roundish, sometimes elliptic or rectangular, sometimes with a strong columnar tendency, the arms abundant, mostly short, sharp, and unbranched.

Discussion:The new species is most notable for its stamens, which approach those of Votomita, and which alone are sufficient to identify it. The puberulence of the inflorescence, and the shorter ovary and calyx lobes, are further distinctions. Except for these differences, M. dimorphandra resembles M. brachyanthera rather closely. After the stamens have fallen the two species can easily be mistaken; however, the anther bases leave impressions in the upper surface of the ovary which aid in the distinction. In M. brachyanthera the maximum widths of the anther imprints opposite the calyx lobes and petals are about the same: those opposite the calyx lobes are 0.9-1.1 mm wide, those opposite the petals are 0.9-1.0 mm wide. In M. dimorphandra one is about twice as wide as the other: those opposite the calyx lobes are 0.9-1.4 mm wide, those opposite the petals are 0.6 mm wide. Also, in M. dimorphandra a minute ridge is left along the middle of each anther imprint, between the two sporangia, in addition to the ridges between the anthers. In M. brachyanthera the central ridges are lacking. Finally, the petal scars in M. dimorphandra are 1.0-1.4 mm wide, while those of M. brachyanthera are 1.4-1.8 mm wide.
Distribution:Amazonas Brazil South America| Rondônia Brazil South America|