IAWA Bulletin n.s., Vol. 3 (1),1982 15 SYSTEMATIC WOOD ANATOMY OF DESMOPSIS, SAPRANTHUS AND STENANONA (ANNONACEAE) by Ben J.H. ter Welle and Jan van Rooden Institute of Systematic Botany, Heidelberglaan 2, 3508 TC Utrecht, The Netherlands Summary The wood anatomy of three related genera record and at the same time description of Sa­ of the Annonaceae has been studied and de­ pranthus as a genus was by Seemann in 1866. scribed as part of a research project on the Afterward authors as e.g. Bentham and Hooker taxonomy of neotropical taxa of the family. (1867) and Prantl (1891), included Sapranthus The wood anatomy of the three genera is char­ in other genera and it was not until 1900 that acterised by the occurrence of many fine apo­ Fries reinstated Saprallthus as a separate genus. tracheal continuous concentric bands of paren­ In the first monographic treatment of Sapran­ chyma. The genera Desmopsis, Sapranthus, and thus (Fries, 1931 a, b) seven species are listed. Stenanona, restricted to Central America, can Desmopsis, consisting of inconspicuous under­ be separated on wood anatomical characters storey treelets, was erected by Safford in 1916, such as element length, ray height and the partly as a segregate from the heterogeneous number of parenchyma bands per mm. A key genus Ullonopsis. He recognised five species. for the genera is presented and the possible Fries (1931 a, b) recognised nine species in his phylogenetic relationships are discussed. Final­ monograph of Desmopsis. The genus Stenallo­ ly, the wood anatomical results are correlated na erected by Standley (1929) is based on Ste­ with data on pollen morphology, flower mor­ nallona pallamellsis, a collection ofG.P. Cooper phology and morphology of fruits and leaves. in the Almirante region of Panama. It is still the only collection of the type species. After­ Introduction wards only one other species was added. More This study forms part of a research project new species were found in Saprtmthus and Des­ on the systematics and wood anatomy of neo­ mopsis. Fries's monograph of the Annonaceae tropical Annonaceae. The genera Desmopsis, (1959) finally included 8 Sapranthus and 16 Sapranthus, Stenanona, Anaxagorea and Rolli­ Desmopsis species. In a forthcoming revision nia have been monographed (to be published in of the three genera treated here, several new the near future) and the wood anatomy of the species will be described (Van Rooden, in three former genera is presented here. Separate prep.). publication seems justified because Desmopsis, Sapranthus and Stenanona form a coherent Wood anatomy group of mutually very closely related genera Since Solereder published his 'Systematische (Fries, 1931a, b; Van Rooden, in prep.). It Anatomie der Dicotyledonen' (1899 & 1908), should be realised that some conclusions pre­ in which he stated that the wood anatomy of sented here might need reconsideration after representatives of the Annonaceae is character­ more genera will have been studied. ised by the presence of fine tangential bands of parenchyma, much research has been carried Historical Survey out. Although many more samples of mature wood have been studied, his general remarks Taxonomy have always been confirmed. So far, Moll and Probably due to their uncommon occurrence, J anssonius (1906) have given the most detailed the genera Desmopsis, Sapranthus, and Stena­ description of Annonaceous woods (21 species nona were recognised as distinct taxa only fair­ belonging to 13 genera). Their descriptions in­ ly recently. In the first monograph of the family dicate that the Javanese Annonaceae are very on a world-wide scale by Dunal (1817) we find similar in their wood anatomy. Nevertheless, the first record of a representative of the pres­ they separated these taxa into four groups. ent genus Sapranthus; the species was collected Hess (1946) studied 21 American genera of this by Mocino and Sesse in Mexico during one of family. He states that th'e woods of all Ameri­ their field trips from 1781 ~ 1803 and was can genera are so similar that it is impossible to­ placed by Dunal in the genus Unolla. The next make a workable key for their identification. Downloaded from Brill.com09/23/2021 07:58:46PM via free access 16 IAWA Bulletin n.s., Vol. 3 (1),1982 Ingle and Dadswell (1953) described the wood Materials and Methods anatomy of 12 genera from the southwest Paci­ A total of 10 species of 3 genera (18 sam­ fic area. Again the wood anatomy of these ples) was examined. Only samples backed by genera is very similar. Nevertheless, some of herbariu~ vouchers, and identified by the sec­ these genera can be separated anatomically, e.g. ond author were used for this study. Sections on the size of the intervascular pits. and macerations were obtained using standard A treatment of the wood anatomy of the techniques. The wood anatomical descriptions Annonaceae, without geographical limitations, are according to the terminology proposed by was made by Vander Wyk and Can right (1956). the Committee on Nomenclature of the lAW A Their main goal was to establish the relation­ (1964). The average element length in samples ships of this family in the Ranalian complex. is based on at least 25 measurements. In the About 400 species (61 genera) were examined. generic descriptions the range of the averages They state: "The wood anatomical features of are given and, between brackets, the minimum the family revealed a remarkable consistency, and maximum values are given. The ray heights which emphasizes the belief that this is a well­ (in cells and !.lm) were obtained by measuring defined natural group. However, there exists a and counting the highest rays in the tangential considerable degree of generic overlap for the sections, exceptions being eliminated. majority of anatomical features, which, there­ The same procedure was followed for the fore, are of doubtful value in attempting to width of the rays in !.lm, i.e., values are based understand the intrafamiliar relationships of on the widest, yet commonly occurring rays. the Annonaceae." This generic overlap has also The bands of tangentially arranged parenchyma been described by Metcalfe and Chalk (1950). are quoted as number per mm. Values were cal­ Asimina is the only genus which can easily be culated from ten countings over distances of 3 distinguished, as also stated by Vander Wyk mm each. The averages of the element lengths and Canright (1956), by the presence of ring­ were also used to calculate the ratio of fibre porous wood. In a study to establish phylo­ length/vessel member length and parenchyma genetic schemes for the Magnoliales, Gottwald strand length/vessel member length, in the de­ (1977) studied 40 genera of the Annonaceae. scription referred to as F /V and P/V ratio. He also concluded that the family forms a very homogeneous structural group in spite of the Results large number of genera and species. Apart from these more or less comprehen­ Desmopsis Safford (Figs. 3, 6) sive studies, various papers, dealing with one or A genus of c. 17 species consisting of small several taxa of the Annonaceae, have been pub­ trees and shrubs up to 7 m and occurring in lished, e.g. Balan Menon (1959), Benoist (1927), Central America. Its distribution centre is Cos­ Jutte (1958), Lindeman and Mennega (\ 963), ta Rica and Panama. The genus has its northern­ Loureiro (1969. 1970, 1971), Loureiro and Da most extension in the state of Veracruz, Mexi­ Silva (1968), Monteiro and Franca (\ 971). co and reaches as far south as the Dept. of Cho­ Normand (1950), Normand and Paquis (1976), c6, Colombia. Nearly all species of Desmopsis and Perez Mogo1l6n (1973). inhabit the shady understorey of moist forests The wood anatomy of Desmopsis, Sapran­ at low altitudes. Only a few species are known thus, and Stenanona has never been described from altitudes up to 1500 m. in detail. Some remarks have been made by Record and Hess (1943) and by Vander Wyk Material studied: D. bibracteata (Robin­ and Canright (1956). A few characters can be son) Safford: Costa Rica, ARG I (Uw 26771), extracted from the tables they present. diam. 6 cm; provo San Jose, Caffrey 159 (Uw At first view. this literature survey makes it 26774), diam. 4 cm; D. stenopetala (Donn. unattractive to embark on a comprehensive Sm.) R.E. Fries: Belize, Crique Negra, Steven­ study of the wood anatomical diversity in An­ son 105 (Uw 24298, ex SJRw 14889), diam. nonaceae. However. in view of the envisaged 6 cm; D. tuxtlensis Van Rooden (ined.): Mexi­ taxonomic and systematic studies at the Insti­ co, region of Los Tuxtlas. slope of the Volcano tute of Systematic Botany in Utrecht, and the San Martin. Edo. Veracruz. Van Rooden 755 availability of pollen morphological data for (Uw 26193), diam. 3 cm; Van Rooden 760 comparison (Walker, 1971) it seemed worth­ (Uw 26195), diam. 3 cm; D. spec.: Panama, while to re-investigate the wood anatomy of region of Almirante. proVo Bocas del Toro, this family in greater detail. in order to com­ Cooper & Slater 47 (Uw 24086, ex SJRw pare various data sets for the clarification of 10146). diam. 4 em. the intrafamily relationships of the Annona­ N.B.: Uw 24455 from Mexico, Los Tuxtlas ceae. (MEXU II). diam. 15 cm. may be identical Downloaded from Brill.com09/23/2021 07:58:46PM via free access IAWA Bulletin n.s., Vol. 3 (1),1982 17 with D. tuxtlensis from the same region, but no Van Rooden 820 (Uw 26209), diam. 4 cm; herbarium specimen is available. Costa Rica, provo Cartago, Turria1ba, Poveda 84 (Uw 26773), diam. 9 cm;S. palanga R.E. Fries: Growth rings faint or absent, marked by an Costa Rica, between Sardinal and EI Coco, increase in the number of tangential bands of provo Guanacaste, Van Rooden 868 (Uw 26216), parenchyma or by zones of fibres with a thicker diam.