taxonID	type	description	language	source
03C387E6FE32FFF82286FF18AED4FDD3.taxon	description	E t y m o l o g y. The specific name, heterogenum, is due to the presence of heterocellular rays. T y p e h o r i z o n. Touro Passo Formation. A g e. Late Pleistocene, 14,600 years (TL). T y p e l o c a l i t y. (29 º 23 ' 55.9 " S / 56 º 42 ' 05.9 " W), Itaqui city, Rio Grande do Sul State, Brazil. D i a g n o s i s. Angiosperm wood, diffuse porosity, numerous vessels in tangential bands; vessels generally solitary, sometimes in radial multiples of 3 to 5, circular to oval in outline, with narrow diameter and short length, helical thickenings absent, tyloses present; simple perforation plates; alternate intervessel pits, vestured, circular, small with lenticular irregular aperture slightly oblique; vessel-ray pits and vessel-parenchyma pits bordered; libriform fibres, non-septate, extremely short and narrow, with simple minute pits; paratracheal axial parenchyma, vasicentric and scanty and apotracheal axial parenchyma diffuse; rays are nume. rous, exclusively heterocellular, composed of procumbent and square marginal cells, short and extremely narrow, simple pits of minute size; mostly uniseriate, less frequently biseriate and triseriate, rarely tetraseriate; aggregate rays are absent. D e s c r i p t i o n. Distinctive growth rings, alternately separated by light and dark bands (Pl. 1, Fig. 1), marked by radially flattened thick-walled latewood fibres versus thin-walled earlywood fibers. Absence of stratification in secondary xylem elements. Wood diffuse-porous (Pl. 1, Figs 1 – 2). Vessels in tangential bands (Pl. 1, Figs 1 – 2), numerous (16 – 36 / mm ²), occupying 25.6 % of the cross section (Pl. 1, Figs 1 – 2). Vessels generally solitary, sometimes in radial multiples of 3 to 5, circular to oval in outline (Pl. 1, Figs 2 – 3). Mean tangential diameter 65.5 (32 – 96) µm, mean length 186.5 (48 – 360) µm. Helical thickenings in vessel elements are absent. Simple perforation plates (Pl. 2, Fig. 4), intervessel pits alternate, small 4.1 (2 – 8) µm, vestured, with lenticular irregular slightly oblique apertures (Pl. 1, Figs 4 – 5). Vessel-ray pits with distinct borders, rounded and bordered (Pl. 1, Figs 4 – 5). Vessel-parenchyma pits are similar to vessel-ray pits. Tyloses (Pl. 1, Figs 2 – 6) and prismatic crystals are present in the marginal square ray cells (Pl. 2, Figs 4 – 6). Fibres libriform, non-septate, with simple and minutely bordered pits 2.3 (1 – 4) µm (Pl. 2, Figs 1 – 4), occupying 45 % of the wood. The fibres are extremely short, mean length 162 (30 – 360) µm, narrow 3.2 (1 – 8) µm and thin-walled 1.9 (1 – 4) µm, with a narrow diameter of 3.9 (2 – 8) µm. The paratracheal axial parenchyma is vasicentric and scanty, occupying only 5.45 % of total wood volume (Pl. 1, Figs 2 – 3). The apotracheal axial parenchyma is diffuse, with dispersed cells between the fibers (Pl. 1, Fig. 2 – 3). Axial parenchyma cells are rectangular (Pl. 2, Fig. 2), mean length 36.9 (16 – 80) µm and mean width 18.5 (8 – 32) µm, constituting a series with mean length 364.8 (176 – 896) µm, composed of 13 (3 – 6) cells. Rays are numerous, occupying 24 % of the volume of the wood (Pl. 1, Figs 1 – 2). They are mostly uniseriate (44 %), less frequent biseriate (27 %), triseriate (21 %) and tetraseriate (8 %) (Pl. 2, Figs 1 – 3). Aggregate rays are absent. Rays are heterocellular, composed of procumbent cells and 1 – 4 rows of square marginal cells, most commonly 2 rows (Pl. 2, Figs 4 – 5). Uniseriate rays extremely short, mean length 204.9 (112 – 424) µm, and extremely narrow, mean width 12.4 (8 – 24) µm, 7 to 27 cells high (Pl. 2, Figs 1 – 3). The multiseriate rays are narrow, mean width 26.8 (16 – 40) µm, 1 to 4 cells wide, and very short, mean length 241.5 (120 – 556) µm, 8 to 27 cells high (Pl. 2, Figs 1 – 3). In tangential section, the ray cells are circular to oval (Pl. 2, Figs 1 – 3) with minute simple pits, ranging from 1 to 4 µm.	en	Benicio, Jose R. W., Pires, Etiene F., Da Rosa, Átila A. S., Spiekermann, Rafael, Uhl, Dieter, Jasper, André (2016): A New Fossil Fabaceae Wood From The Pleistocene Touro Passo Formation Of Rio Grande Do Sul, Brazil. Fossil Imprint 72 (3 - 4): 251-264, DOI: 10.14446/FI.2016.251, URL: http://dx.doi.org/10.14446/fi.2016.251
