Monographs Details: Mouriri dumetosa Cogn.
Authority: Morley, Thomas. 1976. Melastomataceae tribe Memecyleae. Fl. Neotrop. Monogr. 15: 1-295. (Published by NYBG Press)
Scientific Name:Mouriri dumetosa Cogn.
Description:Description - Glabrous tree to 15 m high, often low and shrub-like; young twigs 4-winged, sometimes purplish above, dark gray beneath; bark dark brown; wood hard and fibrous. Leaves tending to be crowded on the twigs, 2.3-4.5 times as long as the internodes, handsome green above, paler beneath; petioles 1.0-1.6 mm long; blades 2.2-5.3 cm long, 1.3-2.8 cm wide, mostly elliptic, sometimes slightly ovate- or obovate-elliptic, rounded to acute or sometimes abruptly acute at the apex, rounded to shallowly cordate at base; midrib grooved above, rounded below; lateral nerves invisible above and below when dry; margins often somewhat revolute. Margins of midrib xylem turned in and downward, sometimes nearly breaking up into two or three individual strands; stomatal crypts a highly modified Type II, averaging in a leaf ca 23-35 µ in diam, 60-66 µ high, 70-128 per sq mm (extremes 20-49 µ diam, 55-70 µ high, 50-150 per sq mm); upper epidermis varying from one to two cells thick in the same leaf, the inner cell of a pair where double much larger than the outer as seen in section, mucilaginous walls occasional, mostly in the inner cell of a doubled set, sometimes in unpaired cells; hypodermis none; free cortical stone cells present along the length of the midrib, becoming much elongated below; terminal sclereids filiform, running from epidermis to epidermis at various angles, weaving about, without a columnar tendency, turning at the epidermises and running next to them before ending, branching very rarely next the upper epidermis, seldom next the lower, with longer ends next the lower than in M. densifoliata. Inflorescences terminal and in the upper leaf axils, 1 per axil, each 1-3-flowered, 13.0-33.0 mm long to base of farthest pedicel measured along the axes and with 2 internodes in that distance; bracts 1.6-3.5 mm long, the upper ones ovate and acute and usually shorter than the lower ones, the latter triangular, the bracts all deciduous by anthesis, the lower and middle ones falling sooner, the uppermost the last to drop. Flowers with a pleasant odor near that of lilies. True pedicels 0.6-2.0 mm long, including those of single flowers and of the center flower in a dichasium, pedicels 0.9(-l.l) mm in diameter when dry; calyx including inferior ovary 3.0-3.6 mm long, broadly campanulate to bowl-shaped overall, the ovary itself rather obconic; free hypanthium none; top of ovary with 10 upright wings radiating outward from the style base, the wings 0.2-0.3 mm high at the center, 0.4-0.6 mm high at each end, bounding the hollows containing the anther ends before anthesis; calyx lobes 0.6-1.0 mm long, 2.0-3.4 mm wide, 1.2-2.0 mm long from top of stamen scar, broadly rounded to truncate, the calyx not splitting between the lobes at anthesis. Petals usually white, sometimes whitish-yellow or pale sulfur-yellow, wide-spreading at anthesis, 8.0-11.0 mm long, 4.0-5.5 mm wide, oblong to ovate-oblong, elliptic-oblong, or ovate-elliptic, acute or short-acuminate at the apex, sessile or narrowed to a short broad claw at base, often notched on one or both sides near the base at least in dry material, the notch apparently a split developed at maturity or perhaps in drying; adaxial surface densely papillose, abaxial one glabrous or papillose. Filaments white, the antesepalous ones 5.0-6.5 mm long, the antepetalous ones 7.0-9.5 mm long; anthers blue to purple, 2.7-3.9 mm long; sporangia horseshoe-shaped, curved over the apex of the anther, extending 1.8-2.1 mm on the side opposite the gland, 1.3-1.5 mm on the gland side, dehiscing by lengthwise slits; gland 0.6-1.2 mm long with a gap of 0-0.15 mm between it and the sporangia; cauda 0.7-1.05 mm long. Ovary 5-locular; placentae basal in each locule, the ovules borne on all sides of a short basal column, 3-5 per placenta, ca 19-22 in all; style 9.5-13.0 mm long, 0.6-0.8 mm in diameter at base when dry and sharply 5-angled there. Fruit yellow, unavailable for study.

Discussion:Mouriri dumetosa and M. densifoliata are very similar; undeniable differences between them exist, but their overall resemblance raises the question of whether they are best considered as species, subspecies, or even varieties. The question cannot be answered satisfactorily at present and therefore the original species rank has not been altered here. The two taxa have different distributions, a matter already discussed under the topic of Distribution, Speciation, and Variation Patterns. The greatest morphological difference between the two lies in the calyx lobes, which are distinctly longer and triangular in M. densifoliata rather than short and broadly rounded. The difference in length of pedicel in single flowers and in the central flower of dichasia is moderately decisive. Lesser differences occur in the wings of the upper internode of the young twigs, which are somewhat wider in M. densifoliata; in the size and frequency of the stomatal crypts; in the form of the terminal foliar sclereids; in the diameter and ridging of the dry pedicel, both of which are greater in M. densifoliata; in the notching of the dry petals; in the size of the gap between the anther gland and sporangia; in the height of the radiating wings on top of the ovary; in the height of the ovary itself, which is greater in M. dumetosa although hard to measure; and in the color and shape of the dry ovary, which in M. densifoliata is usually yellow-orange and is more obconic and with a sharper demarcation where it joins the pedicel, often with a slight constriction there, whereas in M. dumetosa the dry ovary is olive-brown and is more rounded and curved, without any constriction where it joins the pedicel.

In several respects it will be noted that M. densifoliata has larger dimensions than M. dumetosa, which fact might be construed to mean that only a single character is being expressed; however, M. dumetosa has the longer ovary of the two. Opposing trends are also seen in the calyx lobes and leaves, the lobes being more acute in M. densifoliata and the leaves less so, often emarginate, never abruptly acute, while in M. dumetosa the calyx lobes are never acute and the leaves are never emarginate, often abruptly acute.
Distribution:French Guiana South America| Amapá Brazil South America| Pará Brazil South America| Maranhão Brazil South America|

Common Names:Bois perdrix