Acta Botanica Neerlandica 15 (1966) 117-129 Wood anatomy of the genus Euplassa and its relation to other Proteaceae of the Guianas and Brazil Alberta+M.W. Mennega (Botanical Museum and Herbarium, Utrecht) (received December 7th, 1965) Abstract Three of the Proteaceae the in genera belonging to tribe Grevilleeae occur the Guianas and Brazil: Roupala, Panopsis, and Euplassa. The microscopical wood of ofthese has been described structure one genera, Euplassa, not before. Anatomically it identical with proves to be nearly Panopsis which it also resembles in general in the properties. Roupala differs several respects. Within genera differences are fundamental and matter of dimensions. not chiefly a numbers and A key to the is genera given. The relation of these three the other of genera with two members the tribe in South America, Orites and Gevuina, is discussed. Introduction who With the exception of Manieri (1958) included one un- identified of species Adenostephanas (a synonym of Euplassa) in his key of the handbooks to the principal timbers of Brazil, none or publi- cations dealing with the anatomy of South or Central American woods mention the wood of Euplassa (Acosta-Solis, 1960; Basgope, 1962; Kribs, 1928; Record and Mell, 1924; Record and Hess, 1943; Williams, 1936) 1 ). Miss Chattaway (1948a) in her detailed study of the wood anatomy of the Proteaceae did not treat Euplassa, this considered genus not being to comprise any species developing into sizable trees. Neither did Metcalfe and Chalk (1950) give any about the in their of the As particulars genus account family. our material contains several samples of Euplassa from large forest trees from as well as samples small trees, it seemed interesting to study the wood of this genus and to compare its structure with that of other of the Grevilleeae. genera Furthermore it may be worth-while to note whether the results of comparison of the wood anatomy are in agreement with the views of the Johnson and Briggs (1963) on taxonomic interrelationship of the genera. Benoist the of t) (1931) cited Euplassa among genera the Proteaceae known French but he did of the wood of this from Guiana, not give a description genus the other nor of genera. 117 118 A. M. W. MENNEGA Material and methods All wood specimens studied have been collected with herbarium vouchers. Most of the herbarium specimens, either originals or in of the Institute duplicates, are the herbarium Utrecht [U]. Nearly all specimens from Brazil belong to collections identified by Sleumer (1954) and are cited in his treatment of the American Proteaceae; other specimens, mainly from Suriname and French Guiana, were identified by myself. The wood samples are cited fully with particulars about sizes the end of the of each tree at descriptions genus. microtome As far as possible the wood sections were prepared by Treatment without previous treatment except boiling. with hydro- for fluoric acid was necessary only Roupala. Stained and unstained In order sections as well as macerations were prepared. to make the of silica inclusions noticeable sections treated presence more were with crystalline phenol followed by eugenol. For of the testing burning qualities a match-size splinter was taken from the; heartwood. The of the with the terminology descriptions agrees partly Glossary of the International Association of Wood Anatomists (1957), and is partly adapted to the special needs of this family. For classification of numbers and dimensions the recommandations of the Council of the International Association of Wood Anatomists (1937, 1939) have been followed. Besides average data for numbers and sizes the gener- ally occurring lowest and highest figures have been added in brackets. Instead of the usual counting of the rays per mm on a tangential surface the uniseriates have been counted per sq. mm on a tangential section. of macerated For the drawings of elements material a camera of The lucida with a magnification 148 x was used. photographs of from the the transverse surfaces at 10 x magnification were made blocks used for sectioning. Anatomy of the family The main features of Proteaceous woods which can be observed by hand lens are: wide and several millimeters on all Rays very high, conspicuous surfaces; vessels partly in tangential multiples or in tangential chains, always in contact with parenchyma bands which are contiguous with vessels their abaxial the bands and the on sides; narrow, numerous, less with the side parallel, usually more or convex, concave facing broad the vessels the bark, running as festoons between the rays; broad 2 hardly ever in contact with the rays ). in of the three treated here and However, two genera (Euplassa the Panopsis) the characteristic pattern is less pronounced, because 2) For microscopical details, see the paragraph: Remarks on the anatomy. WOOD ANATOMY OF THE GENUS EUPLASSA 119 vessels are scarce and scattered, and the parenchyma bands, moreover, often of the and are independent pores nearly straight. No generic descriptions are included. Though the differences between the of be species one genus are not very important (as may concluded from the descriptions of the species), the discrepancy between the number of species studied and the actually known numbers as given by Sleumer (1954) does not seem to permit a detailed generic account. Roupala has 51 species, Panopsis 11, and Euplassa 20 species; of these 4, 2 and 4 respectively, were studied. The structural differences between the most important genera may be taken from the key. Key 1. Every parenchyma band associated with solitary vessels or vessel fibres thick-walled groups; very with extremely narrow lumen; intervascular 2-4 of vessel members 500 pits ji; average length u Roupala b. Parenchyma bands partly not associated with vessels; fibres moderately thick-walled with a lumen equal to or mostly ex- ceeding the thickness of the walls; intervascular pits medium- sized vessel members the 900 2 ; on average [i long 2.a. Uniseriate rays often over 6 cells high; parenchyma strands often consisting of 6 or 8 or more cells Panopsis 4 b. Uniseriates rarely over cells high; parenchyma strands mostly of 4 cells Euplassa Euplassa Salisb. Euplassa pinnata (Lam.) Johnst. (Plate I, fig. 1; Plate II, fig. 3; Plate III, A) (syn. Adenostephanus guianensis Meisn.) Heartwood pinkish brown, clearly differentiated from the cream- 1.5 3.5 wide the wide coloured, to cm sapwood; rays very conspicuous all on surfaces, producing a silvery ribbon pattern on radial surfaces; rather texture coarse; grain straight; volume weight 0.60-0.70; a of the heartwood burns in 4 of 5 in splinter out samples to grey ash, Uw 4722 to charcoal. Wood structure Growth rings: Absent. Vessels'. A variable percentage solitary, others in tangential pairs or tangential rows of 3-4 (7) or in small clusters, rarely in radial scattered pairs, though often with a tendency to tangential arrangement, 5 in on average (0-10) per sq. mm, in Uw 4722 more variable and some 9-18 places crowded, per sq. mm; cross-section roundish or oval with dimension least for vessels greatest tangentially, at solitary ; 120 A. M. W. MENNEGA diameter on 150 but rather variable tangential average (75-250) fx for various in the clusters often vessel elements the samples, narrower; 880 “tails” often of on average (690-1070) [x long, included, irregular horizontal form ; perforations usually large, nearly or slightly oblique, sometimes in the small in the narrow vessels as openings lateral intervascular walls; wall 5-7 [x thick; pits alternate, nearly round, 6-7 included; with resinous con- [x, apertures occasionally yellowish tents. the di- Tracheids : Often present, associated with vessel clusters, ameter 30-60 800-1000 fi, length /x. Fibre tissue: Walls moderately thick (5-8.5, fx), lumen always wider than the thickness of the walls, generally much wider, diameter fibre in Uw 5754 20-45 /x, length on average 2430 (1500-3850) fx, the 3350 with small borders and extended average length /x ; pits very slitlike ca. 7 numerous on radial and apertures, fx long, equally tangential walls. of Rays: Of two sizes: uniseriates, composed 1 to 2, or up to 4 the cells 100-160 square or upright cells, upright mostly /x axially; multiseriates 10-15 cells wide 325-450 and mostly (6—22) (or // up 800 7-8 in Uw 5754 1.5 to fx); mostly cm high, up to cm; composed of procumbent cells of variable sizes, radially elongated low cells with much shorter and almost irregularly mingled higher, square cells, in the on tangential sections widest cells often more numerous middle formed of a ray; sheath cells locally present; margins usually by one, 1-4 of the latter not occasionally rows square or upright cells, over 150 to vessels rather scarce as the are in contact /z high; pits rays rarely and with vessels, similar to the intervascular pits or larger elongate; cells often with reddish brown contents, which may be concentrated several with around silica bodies; in one sample (Uw 1905) rays sclerified cells Uniseriates 2-5 wide (Plate II, 3). per sq. mm, rays 8—10 per cm. Parenchyma: Predominantly banded, the bands partly associated characteristic with the vessels and vessel multiples in a very way them adjoining laterally and on the abaxial sides; the bands mostly width 1-2 (4) cells wide, running, one pore apart, fairly straight or curved between the few bands slightly large rays, a interrupted or tracheal be beside ending blindly; para parenchyma may present, with the cells the where the bands are contiguous vessels as a few on of adaxial sides of the vessels or as a vasicentric ring one cell layer; number of bands 7 strands variable, on average (5-10) per mm; mostly of4 (2-8) cells; pits to vessels half bordered, generally similar in much to the intervascular pits, part larger and elongate; cells often with brown contents, sometimes with small silica bodies.