Phytolaccaceae

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Phytolaccaceae

Description

Herbs, shrubs or lianas (vines), rarely trees. Leaves alternate, simple, entire, usually petiolate; petiole deeply sulcate adaxially; stipules present or absent. Inflorescence a terminal or pseudoaxillary raceme, spiciform raceme, spike or panicle; pedicels bracteate. Flowers bisexual or unisexual, regular; tepals 4 or 5, united below in a 4- or 5-lobed perianth, inconspicuous or petaloid; stamens 3-20, free or the filaments united at the base, filaments in 1 or 2 whorls, sometimes borne on a hypogynous disk, anthers 2-locular, dorsi- or basifixed, longitudinally dehiscent; ovary superior or half-inferior, 1- to 16-locular, free or partly to wholly connate carpels, ovule 1 per carpel, basal in single carpels, axile in syncarpous ovaries, campylotropous, style, if present, as many as carpels, usually free, stigma capitate, or sessile and penicillate. Fruit a berry, achene, capsule, samara or drupe; seeds 1-numerous, perisperm copious to absent, embryo curved.

Distribution

Guianas: present
A mostly neotropical family of 17 genera and approximately 70-120 species; in the Guianas 6 genera and 9 species.

Wood

Included phloem present in tangential concentric zones, consisting of bundles of xylem and phloem, separated by conjunctive parenchyma (); bands sometimes anastomosing, 200-400 μm wide, 5-6 per cm. Many cells filled with rhombic crystals or long styloids.
Vessels round to oval, solitary and in small multiples, diffuse, regularly distributed or lacking in narrow tangential zones at the outer side of the phloem bands; diameter 40-125 μm, small and large vessels intermingled; 25-40 vessels per mm². Perforations simple. Intervascular pits oval, 4 x 6 μm. Vessel-ray pits similar to intervessel pitting. Vessel member length 300-400 μm.
Rays 1-5-seriate, the multiseriates with short to long uniseriate margins; multiseriate parts up to 750 (2000) μm high, often slightly irregularly built, mainly composed of procumbent cells, the larger rays with sheath cells; margins like uniseriate rays composed of procumbent, square and upright cells; up to 1250 μm, 8 cells high, 5-8 per mm.
Parenchyma very scanty paratracheal as fusiform cells or 2-celled strands; strands 120-150 μm high; as conjunctive tissue in the alternating with the islands of included phloem.
Fibres with moderately thick-walled, walls 3-4 μm, lumina up to 15 μm wide. Pits simple, slit-like, numerous on radial walls, scanty on tangential walls.
Crystals of different size and shape, varying from rhombic and fusiform crystals to styloids in the included phloem (Carlquist 1988).
In the Guianas, three genera occur that are known to include woody species. The only species represented in the Utrecht wood collection is the scandent shrub Seguieria americana.
As far as known the wood is of no commercial value.
A. Carlquist, S. - in Comparative Wood Anatomy. Systematic, Ecological, and Evolutionary Aspects of Dicotyledon Wood. 1988, B. Lindeman, J.C., A.M.W. Mennega and W.J.A. Hekking. - in Bomenboek voor Suriname. Herkenning van Surinaamse houtsoorten aan hout en vegetatieve kenmerken. 1963, C. Metcalfe, C.R. & L. Chalk., Wood structure and conclusion of the general introduction in Anatomy of the Dicotyledons vol. II. 1983, D. Record, S.J. & R.W. Hess. - in Timbers of the New World. 1943

Notes

ACHATOCARPACEAE is closely related to PHYTOLACCACEAE, differing from the latter by the absence of raphides and styloids, the morphology of the sieve element plastids, the compound, 1-ovulate ovaries and the absence of anomalous secondary growth (Bittrich, 1993). The genus Achatocarpus Triana ranges from Texas and Mexico south to Argentina, and has an unconfirmed report from the Guianas. No Guianan specimens have been received for study. The South American Achatocarpus pubescens C.H. Wright, with racemes to 4.5 cm long and 2 stigmas, superficially resembles Trichostigma octandrum (L.) H. Walt. (PHYTOLACCACEAE) which has racemes to 13 cm long and 1 stigma.