Monographs Details: Mouriri froesii Morley
Authority: Morley, Thomas. 1976. Melastomataceae tribe Memecyleae. Fl. Neotrop. Monogr. 15: 1-295. (Published by NYBG Press)
Scientific Name:Mouriri froesii Morley
Description:Description - The epithet acknowledges the invaluable collecting activities of Ricardo de Lemos Froes, the discoverer of this species. Midrib xylem tubular; stomatal crypts Type III, averaging in a leaf ca 46m in diam, 25 µ high, 130 per sq mm (extremes given above); upper epidermis basically one cell thick but occasional cells enlarge and slide partly under the adjoining cells; these enlarged cells contain mucilaginous walls; hypodermis none; free cortical stone cells extending along the midrib for its length; terminal sclereids when stellate with central bodies round to rectangular, 1-2 times as long as wide, with few to many short to medium mostly blunt horizontal arms and prominent columnar arms.

Latin Diagnosis - Plantae glabrae lignosae, habitu ignoto; ramuli juvenes 4-alati. Petioli 1.2-1.8 mm longi; laminae 6.7-10.5 cm longae, 2.9-4.1 cm latae, ovato-ellipticae vel ellipticae, ápice acuto usque acuminato, basi acuta usque rotundata et cordata incisura 0.2-0.6 mm profunda; superficies costae mediae canaliculata, pagina inferior prominens, anguste 2-alata ad ángulos; nervi laterales desuper obscure visibiles, desubter visibiles in sicco. Cryptae stomatatae 22-73 µ diametris 20-31 µ altae, 100-160 in mm2; sclerides terminales foliariae stellatae usque columnares. Pedunculi 1-flori, 1-2 in quoque later ad nodos ramulorum aphyllorum usque 2.0 mm crassorum et ad nodos aphyllos intra zonam foliorum, singuli 1.7-2.8 mm longi cum internodiis 2;bractaeae 1.0-1.4 mm longae, triangulares, saltern sub anthesi persistentes; pedicelli 1.4-2.2 mm longi. Calyx ovarium inferior includens 10.5-11.2 mm longus, fere omnino connatus, lobis 0.1 mm longis, 0.3 mm latis, regulariter vel irregulariter rumpens sub anthesi, 5.3 mm findens, 5.3 mm longus ab staminibus; hypanthium liberum 3.2-3.8 mm longum. Petala immatura 5.0 mm longa, 4.0-4.4 mm lata, late ovata usque elliptica, acuta, ungue basali. Antherae 4.6-5.0 mm longae; thecae 4.3-4.7 mm longae; glándula 0.8-1.0 mm longa cum centro 2.3-2.7 mm ab apice antherae. Ovarium 4-loculare, placentatione axialibasilari; ovula 3-4 in quoque loculo. Fructus ignotus.

Discussion:The major characteristics of this species are the grooved midrib, the single flowers on their short peduncles, the nearly complete fusion of the calyx, and the high position of the anther gland. The closest relative of M. froesii is undoubtedly M. tessmannii. Unfortunately, the only material of the latter was destroyed at Berlin, so that comparisons can only be made from the photograph of the type and from the description. On these bases M. froesii differs from M. tessmannii in having smaller leaves, a slightly cordate leaf base, shorter petiole, distinctly grooved midrib, invisible lateral nerves on dry mature leaves, shorter peduncles and pedicels, glabrous calyx and pedicel, smaller flower, and shorter anthers. The character of the upper surface of the midrib in M. tessmannii is not certain, but appears to vary from flat to slightly grooved. In addition, the blade surface of the latter species appears to be minutely rugose and pitted, where as it is rather smooth in M. froesii, and finally, the petals in M. tessmannii are reported by Markgraf to be laterally fused, while the immature ones in the buds of M. froesii are separate in the lower 3/4 and stuck together above; probably they separate completely at maturity. No open flowers nor mature petals are present in Froes’ collection.

Two other species seem of fairly close relation to M. froesii, M. rhizophorifolia and M. completens. From M. rhizophorifolia, M. froesii is distinguished by its narrower leaf proportion and grooved midrib, its stomatal crypts, single epidermis and less specialized terminal sclereids, its flower bud which lacks an abruptly acuminate tip, and its longer anthers with their high-placed glands. From M. completens, M. froesii differs in having smaller leaves, a smaller notch at the blade base, the grooved midrib, stomatal crypts, and single and smaller flowers.
Distribution:Brazil South America| Amazonas Brazil South America|