Trichilia septentrionalis C.DC.

  • Authority

    Pennington, Terence D. 1981. Meliaceae. Fl. Neotrop. Monogr. 28: 1-359, 418-449, 459-470. (Published by NYBG Press)

  • Family

    Meliaceae

  • Scientific Name

    Trichilia septentrionalis C.DC.

  • Type

    Type. Spruce 1890, Brazil, Rio Negro between Manaus and Barcelos, young fl, fr (holotype, G-DC; isotypes, BM, G, K, M, P).

  • Synonyms

    Trichilia moritzii C.DC., Trichilia polyneura C.DC., Trichilia lanceolata Pittier, Trichilia magnifica Baehni & J.Macbr., Trichilia eurysepala Harms, Trichilia krukovii A.C.Sm., Trichilia grandis Lass. & Maguire

  • Description

    Species Description - Young branches finely puberulous or rarely short pubescent, indumentum persistent, pale brown, without lenticels. Bud scales absent. Leaves imparipinnate (15-)20-40(-56) cm long; petiole narrowly winged or semiterete, rhachis ± terete, densely puberulous to glabrous; petiolule (1.5-)3-10(-15) mm long, terminal one often much longer. Leaflets nearly always opposite rarely alternate, (5-)7-11, elliptic, oblong or oblanceolate, apex narrowly or broadly, short to long acuminate or attenuate, base usually narrowly to broadly cuneate or attenuate rarely ± truncate, terminal leaflet often with a longer more tapering base than laterals, chartaceous or less frequently subcoriaceous, (9-) 14-26(-32)[ 19.9] cm long, (4-)5-12(-16)[7.7] cm broad, lower leaflets often much smaller, upper midrib usually puberulous and lamina glabrous or with a few granular red papillae, lower midrib and lamina puberulous or glabrous, often intermixed with granular red papillae, often faintly glandular-punctate and -striate; venation eucamptodromous, secondaries (10-)15-25(-32) on either side of midrib, ascending, straight or arcuate, usually parallel rarely convergent; intersecondaries short or absent; tertiaries faint to prominent, oblique, ± parallel. Flowers unisexual, plants monoecious or ?dioecious; inflorescence axillary, 10-40 cm long, a laxly-branched, narrowly to broadly pyramidal panicle, flowers rather densely clustered on lateral branches, usually minutely puberulous; pedicel very stout, to 0.5 mm long or flowers sessile. Calyx patelliform to cyathiform, (1-)1.5-2.5(-3) mm long, sepals (4-)5, free, strongly imbricate, broadly ovate, orbicular or reniform, apex rounded, puberulous, ciliate. Petals 5-7, strongly imbricate, (2.5-)3-5.5(-6) mm long, (1.5-)2-3(-4) mm broad, usually broadly spathulate, oblanceolate or oblong, less frequently elliptic or ovate, apex rounded or obtuse, appressed puberulous to sericeous outside, glabrous inside. Staminal tube cyathiform, urceolate or short cylindric, 2-4.5 mm long, 1-2.5(-3.5) mm broad; filaments usually completely fused, occasionally free at apex or tube split down one side; margin of tube with 6-10 subulate appendages (each appendage sometimes subdivided to base) alternating with anthers and 0.25-1.5 times their length, outside sparsely hairy in upper half or glabrous, inside sparsely hairy to barbate in throat or glabrous; anthers 6-10, (0.8-) 1-1.4 mm long, glabrous; antherodes narrow, shrunken, not dehiscent, without pollen. Nectary in [male] flowers a thick glabrous annulus fused with base of staminal tube, in [female] flowers reduced to a small annulus around base of enlarged ovary or absent. Ovary ovoid or conical, (2-)3 (-4)-locular, loculi uniovulate, densely to sparsely pubescent or tomentose rarely subglabrous; style short, rather stout, pubescent or glabrous; style-head ± discoid, bearing a conical 3-lobed stigmatic area, below or equalling anthers. Pistillode usually greatly reduced and embedded in fleshy nectary containing small nonfunctional ovules, style thin and usually glabrous. Fruit produced in large axillary clusters to 25 cm long. Capsule oblong, obovoid or ellipsoid, apex acute to rounded, base rounded to tapered, smooth to slightly verrucose, densely puberulous, 1.3-3.2 cm long, 0.9-1.7 cm broad, 3-valved, valves opening widely and sometimes reflexing; pericarp 1-2 mm thick; endocarp cartilaginous. Seeds 1-2 in each fruit, 1-2.5 cm long, surrounded by a thin 3-partite fleshy arillode which completely covers seed except for small patch at base; arillode attached to seed coat at apex and along part of adaxial surface; seed coat thin and soft. Embryo with thick, plano-convex, collateral cotyledons; radicle apical, included. Endosperm absent.

  • Discussion

    It is not yet clear whether this species is ever dioecious. Personal observations in central Amazonia showed it to be monoecious, all fallen flowers beneath the tree were male and all those remaining on the inflorescences female. Examination of many herbarium specimens has not revealed any in which both male and female flowers are present on the same inflorescence or on different inflorescences on the same plant. Herbarium material therefore gives the impression of dioecy. Male flowers are very ephemeral (cf. Carapa guianensis, where these last for 810 hours only) (Pennington, pers. obs.). Many apparently female inflorescences probably contained male flowers which have fallen, but it is difficult to account for those inflorescences bearing only male flowers unless the species is dioecious or male and female flowers are produced on different inflorescences on the same plant.

    Relationships Trichilia septentrionalis is a variable species but the variation is diffuse and involves only one or a few quantitative characters in any one part of its range. The characters are leaf and leaflet size, number of secondary veins and their distribution, size of calyx, number of anthers and size of fruit.

    Leaf and leaflet size vary widely within single populations and on single individuals (e.g. Pennington et al. 9902, 9929 from central Amazonia). The secondary veins are typically 15-25 on either side of the midrib, ± straight and parallel. A few collections are known from western Amazonia in which the leaflets have only

    10-15 rather convergent secondary veins. In the type collection of T. eurysepala (Tessmann 4435) this feature is correlated with a rather large calyx and a flower containing only 6 anthers (typically 9-10). However, there are some specimens (e.g. Klug 2934) from the same area in which the anther number is reduced but the leaflet venation is that of typical T. septentrionalis and other specimens (e.g. Klug 2742) in which the anther number is normal but the secondary venation convergent. Anther number is now known to vary continuously from 6-10 within and between populations.

    Trichilia moritzii was described by C. de Candolle from two collections from northern Venezuela (Moritz 1681, Fendler 138) which were supposedly characterized by large fruit (ca. 3 cm long) and flowers with 6 anthers. However the flowers of Fendler 138 have 10 anthers which just confirms the variability of this character. Other large-fruited collections have been made from the same general area and all appear to be from 1000-2000 m altitude. Other collections from the same region have smaller fruit (e.g. Pittier 15387) which are no bigger than those of the lowland populations. Apart from the fruit size some of the higher elevation specimens also have a rather coriaceous leaflet but again these intergrade with specimens from lower altitudes.

    The differences in fruit size and leaflet texture between lowland and highland plants of this species is similar to that between lowland and highland populations of Guarea kunthiana in Costa Rica and Andean South America. In both species these features are probably a response to the differences in altitude and climate, but they are not great or consistent enough to be used to subdivide species.

    Flowers: Floral biology. Male and female flowers (Fig. 21B, C) show well marked morphological differences, the male having a reduced pistillode and well developed fleshy annular nectary, and the female a well developed ovary and a reduced or absent nectary. The disposition of the anthers is also characteristic. They are curved inwards to restrict the entrance into the staminal tube, which in the female flowers is effectively blocked by the position of the style-head and stigma between or slightly below the anthers.

    Field characters: Trichilia septentrionalis is a small to medium sized tree up to 20 m high with smooth grey or grey-brown bark, which may be finely longitudinally cracked or lenticellate. The species is distinctive on account of the pale green undersurface of the leaflets, the rather prominent parallel secondary venation, and the large erect axillary panicles. The flowering season throughout its range extends from May to October but in western and northern Amazonia there are a few records from January to March. Mature fruit is recorded from January to July. The flowers are greenish-cream in color and sweet-scented. The fruit ripens red and contains a seed surrounded by a red arillode.

  • Common Names

    Bicauy, Sacha Requia

  • Distribution

    From Costa Rica and Panama to Venezuela, also in Amazonian Ecuador, Colombia and Peru, western and central Amazonian Brazil, the Guianas, Amapa Territory and Para, Brazil. Usually a tree of non-flooded lowland forest, but in Venezuela ascending to 2000 m in the Coastal Cordillera. In the region of Manaus in central Amazonia, it is common in forest on brown sands.

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