sign in sign up
<<
Home , Amburana, Amburana cearensis, Ateleia, Baphiopsis, Bobgunnia, Bocoa

IAWA Journal, Vol. 22 (2), 2001: 193–199

WOOD ANATOMY OF MATHEWSII

(, PAPILIONOIDEAE, LEGUMINOSAE) by Peter Gasson & Elspeth J. Wray Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AB, United Kingdom

SUMMARY The Cyathostegia consists of one or possibly two from Ecuador and Peru. The wood anatomy of C. mathewsii (Benth.) Schery is described, thereby completing generic coverage of wood anatomy in the tribe Swartzieae sensu Polhill (1994b). In Cyathostegia, vessels are mainly in radial multiples, axial parenchyma is relatively sparse, storied and mainly paratracheal, and rays are 1–2-seriate and irregularly storied. Its wood anatomy is compared with that of other genera in the closely related tribes and Swartzieae, both of which have included Cyathostegia. The similarities and differences between Cyathostegia, and are emphasised. Key words: Amburana, Ateleia, Cyathostegia, Sophoreae, Swartzieae.

INTRODUCTION

Cyathostegia comprises one, or possibly two species of or small in Ecua- dor and Peru. Wood specimens of this genus were unavailable for previous studies of Sophoreae (Gasson 1994) and Swartzieae (Gasson 1996), and no published informa- tion on the wood anatomy of this genus could be found. A wood sample of Cyathoste- gia mathewsii has recently been collected in Ecuador, allowing us to provide a wood description and compare the wood anatomy of the genus with other Sophoreae and Swartzieae. Generic descriptions of the tribe Swartzieae as circumscribed by Polhill (1994b) are now complete (Gasson 1994, 1996; Gasson & Webley 1999). Polhill (1981) associated Cyathostegia with seven other genera of Sophoreae in the Myroxy- lon group. The closest relative of Cyathostegia is considered to be Ateleia (e.g. Rudd 1968; Herendeen 1995; Ireland et al. 2000; Pennington et al. in press). Their seeds share the same uncommon amino acids (Janzen 1989), they have the same type of endothecial thickenings (Manning & Stirton 1994) and their general aspect and habi- tat requirements are similar (Rudd 1968). Cyathostegia has in the past been reduced to synonymy under Ateleia (Hutchinson 1964), and Janzen (1989) was tempted to view Cyathostegia as an Ateleia. This paper compares the wood anatomy of Cyatho- stegia and Ateleia with that of Amburana. Amburana is sister to these two genera in Herendeenʼs cladograms (1995, see also Polhill 1994a), but is widely separated from the “Swartzioid” clade recognized by Ireland et al. (2000) and Pennington et al. (in press), which includes , and (the latter consisting of the two African “Swartzia” species, see Kirkbride & Wiersema 1997), but not Amburana.

Downloaded from Brill.com09/30/2021 03:38:03AM via free access 194 IAWA Journal, Vol. 22 (2), 2001 Gasson & Wray — Wood anatomy of Cyathostegia 195

MATERIAL AND METHODS

The wood description of Cyathostegia mathewsii is based on a sample collected in 1997 by G.P. Lewis and A. Bruneau in Loja province, Ecuador (altitude 1900 m, c. 79° 27' W; 3° 57' S), field collection number 3537, Kew wood collection number Kw 74937. The species was found growing as shrubs up to 1.5 metres high, in dry ravines and along the roadside, especially on calcareous soil. The wood sample was approximately 2 cm in diameter, including bark, from the largest stem found, al- though Rudd (1968) describes the species as a or to 8 metres tall and larger wood samples may become available in the future. In view of the juvenile nature of the wood, the vessel and ray measurements in the description should be treated with some caution. Note that Bentham (1870) incorrectly spelt the specific epithet as mat- thewsii in the protologue. Helen Ireland has pointed out that the species was named after the original collector of Cyathostegia material held at the Natural History Mu- seum, who was probably either William Mathews or Ferdinand Schuyler Mathews, but no initials were given. For details of the wood collections for wood samples cited in the Discussion (Tw = Tervuren, CTFw = Nogent-sur-Marne), see Stern (1988).

WOOD DESCRIPTION (Figures 1–6)

Cyathostegia mathewsii: wood diffuse-porous without growth rings. Vessels solitary (24–29%), in pairs, many radial multiples of 3 to 4, and occasional clusters of up to 5. Vessel elements 14–(34)–62 μm in tangential diameter, relatively short (124–(159) –200 μm), with alternate, polygonal vestured pits (6.5–8 μm in diameter) and simple perforation plates. Vessel-ray pitting similar to intervascular pitting in shape and size. Fibres mainly gelatinous, thick-walled with narrow lumina, non-septate, with some apparently simple pits. Axial parenchyma scanty paratracheal, diffuse, occasionally winged aliform and confluent, also in irregular bands up to 3 cells wide; storied, usu- ally 2 cells per axial parenchyma strand, occasionally 3- to 5-celled. Rays 8–12 per mm, 3 to 35 cells high, mainly 2 cells wide, occasionally uniseriate; irregularly storied, sometimes axially fused over 2 storeys. Most rays homocellular, composed of procum- bent ray cells, but some heterocellular, with procumbent, square and upright cells mixed throughout the ray. Crystals not found.

SYSTEMATIC DISCUSSION

The taxonomic status of Cyathostegia has long been a matter of debate. It was ini- tially included as a section of Swartzia in the tribe Swartzieae (Bentham 1865) and raised to generic level by Schery (1950). Cyathostegia occupies an ambiguous posi- tion among genera of the tribes Swartzieae and Sophoreae, having been switched repeatedly between the two (see Rudd 1968; Cowan 1981; Polhill 1981, 1994b). It has also been placed either within (e.g. Rudd 1968) or Papilionoideae (Polhill 1981), or in a transitional zone between them (see Polhill 1994a). This area of systematics is still controversial, but it is now accepted that Swartzieae and

Downloaded from Brill.com09/30/2021 03:38:03AM via free access 194 IAWA Journal, Vol. 22 (2), 2001 Gasson & Wray — Wood anatomy of Cyathostegia 195

Fig. 1–4. Cyathostegia mathewsii. – 1 & 2: TS, vessels mainly in radial arrangement, many gelatinous fibres, relatively sparse axial parenchyma, some banded and apparently marginal. – 3 & 4: TLS, rays 1 to 2 cells wide and irregularly storied. — Scale line for 1 & 3 (on 1) is 200 μm, for 2 & 4 (on 2) is 100 μm.

Downloaded from Brill.com09/30/2021 03:38:03AM via free access 196 IAWA Journal, Vol. 22 (2), 2001 Gasson & Wray — Wood anatomy of Cyathostegia 197

Fig. 5 & 6. Cyathostegia mathewsii. – 5: RLS, vestured vessel-ray pitting. Scale is 25 μm. – 6: SEM, vestured intervessel pitting seen from outer (middle lamella) side of vessel. Scale is 5 μm.

Sophoreae are para- or polyphyletic (e.g., see Herendeen 1995; Doyle 1995; Ireland et al. 2000; Pennington et al. in press). Polhill (1981) originally included Cyathostegia in Sophoreae, recognising the tribe as one of convenience, and subsequently sug- gested absorption of the basal members of the tribe, including Cyathostegia, into a revised Swartzieae (Polhill 1994a, b). Cladistic analyses of pollen morphology (Ferguson & Schrire 1994) and of flower, fruit, pollen and leaf characters (Herendeen 1995) demonstrated that Swartzieae is polyphyletic, and Herendeen (1995) suggested the transfer of all genera of Swartzieae to Sophoreae. Chappill (1995), using a cladistic analysis of largely morphological data, found Sophoreae to be polyphyletic as well, and the heterogeneous distribution of a 50 kb chloroplast DNA inversion within these tribes (Doyle et al. 1996) and studies of variation in the chloroplast gene rbcL also indicate para- or (Doyle 1995). This heterogeneity is reflected in previous studies based on wood anatomy, where there is no clear delimitation between the two tribes (Gasson 1996). The wood anatomy of Cyathostegia is compared here with that of all genera in Swartzieae and Sophoreae described by Gasson (1994, 1996), Fujii et al. (1994), Gasson and Webley (1999) and Baretta-Kuipers (1981). Cyathostegia has a distinctive wood anatomy, the principal differences from other genera being in vessel grouping, axial parenchyma distribution and ray structure. Radial multiples of vessels are common in Cyathostegia but relatively uncommon in other Sophoreae and Swartzieae, occurring in , Bocoa alterna and some species of , and (Gasson 1994, 1996). Intervessel pit diameter is a significant diagnostic feature in some papilionoid (Gasson 1999), and is very similar in Cyathostegia (6–8 μm), Ateleia (5–9 μm) and Amburana (6–10 μm), which are compared below in more detail. The axial parenchyma distribution is

Downloaded from Brill.com09/30/2021 03:38:03AM via free access 196 IAWA Journal, Vol. 22 (2), 2001 Gasson & Wray — Wood anatomy of Cyathostegia 197

paratracheal, and the overall pattern is similar to that in , Lovanafia, Ca- dia, , Baphia, , Candolleodendron, , , and Swartzia. However, axial parenchyma often shows considerable variation within a single genus, and occurs in many different forms in the Swartzieae and Sophoreae (Gasson 1994, 1996). Since only one wood sample of Cyathostegia was examined, the full range of variation in this species may not have been explored. Calcium oxalate crystals, present in chambered axial parenchyma cells in virtually all papilionoid gen- era, and in ray cells in some genera, were not found in Cyathostegia. However, they are of varying abundance in many legume genera and can be overlooked when rare. Their absence is particularly surprising in a species that favours calcareous soils. Polhill (1981) associated Cyathostegia with seven other genera in the Sophoreae, in the Myroxylon group. In the absence of Cyathostegia, Gasson (1994) found the group to be reasonably coherent in terms of wood anatomy. Most genera in this group have regularly storied rays (, Myroxylon, , and ), but varies from having short, regularly storied rays that are 1–2-seriate (e.g. Tw 20041 from Peru) to taller, wider rays that show a clear ten- dency towards storeying only when they are adjacent to axial parenchyma (e.g. CTFw 30577 from ). This range of variation in ray storeying is mirrored in Ateleia. Amburana and some species of Ateleia (e.g. A. glazioveana) have very similar pat- terns of abundant aliform and confluent parenchyma, butCyathostegia and other spe- cies of Ateleia (e.g. A. popenoei) have much less abundant parenchyma. Cyathostegia is grouped with Ateleia and Amburana by both Polhill (1994b) and Herendeen (1995). In Cyathostegia and Ateleia, the axial parenchyma is storied (2–4-celled), the shorter rays (generally 1 to 2 cells wide) are storied and the taller rays are axially fused over two or more parenchyma storeys. The rays in Amburana tend to be wider and taller (3–5 cells wide and up to 25 cells high). All three genera share predominantly irregu- larly storied rays, unlike the other Myroxylon group genera which have regularly storied rays. The rays in the three genera are also often heterocellular, although sometimes only slightly so. Axial parenchyma is much less abundant in Cyathostegia, greatly affecting the appearance of the wood and the ease with which parenchyma storeying can be seen in TLS. Gelatinous fibres are particularly abundant in Cyathostegia, but also often present in Ateleia and Amburana. Their presence could be linked to the seasonally dry habitats they inhabit (Rudd 1968; Lorenzi 1992; G.P. Lewis, pers. comm.), but may also be due to differences in habit (Ateleia and Cyathostegia tend to be shrubs or small trees, whereas Amburana is a larger, timber-producing tree), since gelatinous fibres are often found in tension wood.Amburana , Ateleia and Cyathostegia are the only three genera in the basal Papilionoideae that exclusively inhabit season- ally dry tropical forests rather than more mesic vegetation (Pennington, pers. comm.). In comparison with all other genera of Sophoreae and Swartzieae, Cyathostegia shows an overall similarity to genera traditionally regarded as belonging to Swartzieae (sensu Polhill 1981, 1994b). Using the character coding in Gasson (1994, 1996), the wood anatomy of Cyathostegia is identical to that of Candolleodendron, and very similar to Swartzia, Bocoa prouacensis/viridiflora, Zollernia and Baphiopsis. Cyatho- stegia fits most comfortably into a basal group centred around some of the original

Downloaded from Brill.com09/30/2021 03:38:03AM via free access 198 IAWA Journal, Vol. 22 (2), 2001 Gasson & Wray — Wood anatomy of Cyathostegia 199 members of Swartzieae. This echoes Doyle et al. (1996), who found that a 50-kb chloroplast DNA inversion was absent from representatives of all Caesalpinioid tribes, Mimosoideae, and some Swartzieae and Sophoreae, but present in other Papilionoideae. The Papilionoideae could therefore be divided into a ʻcoreʼ group of genera lacking the inversion, to include most Swartzieae and some Sophoreae, and a higher clade possessing it (see Ireland et al. 2000; Pennington et al. in press). Although Cyatho- stegia was not included in the molecular analyses, Ateleia was found to lack the inversion, indicating that Cyathostegia too should be placed within the ʻcoreʼ group. Both molecular and wood anatomical data indicate that following further analysis, Ateleia, Cyathostegia, Swartzia, Bocoa and perhaps a few more genera could consti- tute a redefined Swartzieae.

ACKNOWLEDGEMENTS

We would like to thank Gwilym Lewis for supplying the wood sample, and Helen Ireland for her helpful advice on Ateleia and Cyathostegia. Paula Rudall suggested numerous improvements to the original manuscript, and Pat Herendeen and Toby Pennington are thanked for their thoughtful reviews.

REFERENCES

Baretta-Kuipers, T. 1981. Wood anatomy of the Leguminosae: its relevance to . In: R.M. Polhill & P.H. Raven (eds), Advances in Legume Systematics, Part 2: 677–705. Bentham, G. 1865. In: G. Bentham & J.D. Hooker, Genera Plantarum 1 (2): 581. Bentham, G. 1870. In: J.D. Hooker (ed.), Icones Plantarum: 51. Icon 1064. Chappill, J.A. 1995. Cladistic analysis of the Leguminosae: the development of an explicit phylogenetic hypothesis. In: M. Crisp & J.J. Doyle (eds), Advances in Legume System- atics, Part 7: 1–9. Cowan, R.S. 1981. Swartzieae. In: R.M. Polhill & P.H. Raven (eds), Advances in Legume Systematics, Part 1: 209–212. Doyle, J.J. 1995. DNA data and legume phylogeny: a progress report. In: M. Crisp & J.J. Doyle (eds), Advances in Legume Systematics, Part 7: 11–30. Doyle, J.J., J.L. Doyle, J.A. Ballenger & J.D. Palmer. 1996. The distribution and phylo- genetic significance of a 50-kb chloroplast DNA inversion in the flowering family Leguminosae. and Evolution. 5 (2): 429–438. Ferguson, I.K. & B.D. Schrire. 1994. A cladistic analysis of the pollen morphology of the tribe Swartzieae (Leguminosae). Acta Bot. Gallica 141: 207–215. Fujii, T., P. Baas, P. Gasson & J. Ridder-Numan. 1994. Wood anatomy of the Sophora group. In: I.K. Ferguson & S. Tucker (eds), Advances in Legume Systematics, Part 6: 205–249. Gasson, P. 1994. Wood anatomy of the tribe Sophoreae and related Caesalpinioideae and Papil- ionoideae. In: I.K. Ferguson & S. Tucker (eds), Advances in Legume Systematics, Part 6: 165–203. Gasson, P. 1996. Wood anatomy of the tribe Swartzieae with comments on related Papilionoid and Caesalpinioid Leguminosae. IAWA J. 17: 44–75. Gasson, P. 1999. Wood anatomy of the tribe Dipterygeae with comments on related Papilionoid and Caesalpinioid Leguminosae. IAWA J. 20: 441–455. Gasson, P. & P. Webley. 1999. Wood anatomy of venusta (Swartzieae, Papilionoideae, Leguminosae). IAWA J. 20: 1–8.

Downloaded from Brill.com09/30/2021 03:38:03AM via free access 198 IAWA Journal, Vol. 22 (2), 2001 Gasson & Wray — Wood anatomy of Cyathostegia 199

Herendeen, P.S. 1995. Phylogenetic relationships of the tribe Swartzieae. In: M. Crisp & J.J. Doyle (eds), Advances in Legume Systematics, Part 7: 123–132. Hutchinson, J. 1964. The Genera of Flowering 1: 320–331. Clarendon Press, Oxford. Ireland, H., R.T. Pennington & J. Preston. 2000. Molecular systematics of the Swartzieae. In: P.S. Herendeen & A. Bruneau (eds), Advances in Legume Systematics, Part 9: 217–231. Janzen, D.H. 1989. Natural history of a wind pollinated central American dry forest legume tree (Ateleia herbert-smithii Pittier). In: C.H. Stirton & J.L. Zarucchi (eds), Advances in Legume Biology. Monogr. Syst. Bot. Missouri Bot. Gard. 29: 293–376. Kirkbride, J.H. & J.H. Wiersema. 1997. Bobgunnia, a new African genus of tribe Swartzieae (, ). Brittonia 49: 1–23. Lorenzi, H. 1992. Arvores Brasileiras: 191 Editora Plantarum, Brasil. Manning, J.C. & C.H. Stirton. 1994. Endothecial thickenings and phylogeny of the Legumi- nosae. In: I.K. Ferguson & S. Tucker (eds), Advances in Legume Systematics, Part 6: 141–163. Pennington, T., M. Lavin, H. Ireland, B. Klitgaard, J. Preston & J-M. Hu. [In press]. Phylo- genetic relationships of basal papilionoid legumes based upon sequences of the chloroplast intron trnL. Systematic . Polhill, R.M. 1981. Sophoreae. In: R.M. Polhill & P.H. Raven (eds), Advances in Legume Systematics, Part 1: 213–230. Polhill, R.M. 1994a. Classification of the Leguminosae. In: F.A. Bisby, J. Buckingham & J.B. Harborne (eds), Phytochemical Dictionary of the Leguminosae, Part 1: xxxv–xlviii. Polhill, R.M. 1994b. Complete synopsis of legume genera. In: F.A. Bisby, J. Buckingham & J.B. Harborne (eds), Phytochemical Dictionary of the Leguminosae, Part 1: xlix–lvii. Rudd, V.E. 1968. A resumé of Ateleia and Cyathostegia (Leguminosae). Contrib. U.S. Nat. Herb. 32: 385–411. Schery, R.W. 1950. Cyathostegia (Benth.) Schery, gen. nov. Ann. Missouri Bot. Gard. 37: 401. Stern, W.L. 1988. Index Xylariorum: Institutional wood collections of the world. Third edi- tion. IAWA Bull. n.s. 9: 203–252.

Downloaded from Brill.com09/30/2021 03:38:03AM via free access