IAWA Bulletin n.s., Vol. 2 (1),1981 41
A NEW RECORD OF VESTURED PITS IN CISTACEAE
by
Pieter Baas* and Ella Werker**
Summary Vestured pits are recorded and documented Bailey (1933) in his classical paper on ves for the genus Cistus. They also occur in some tured pits in dicotyledons included one (un other representatives of the family Cistaceae. specified) species of Cistaceae in his survey, This is their first record for the family as well and found the pits non-vestured. In later ac as for the order Cistales, Bixales or Violales, to counts of the wood anatomy of Cistaceae (e.g. which Cistaceae are usually assigned. Metcalfe & Chalk, 1950; Greguss, 1959) ves tured pits also remained unnoticed. Records of vestured pits in families not considered to have In the course of a wood anatomical survey them by Bailey have been published by several of trees and shrubs from Israel and adjacent authors (e.g. Meylan & Butterfield, 1974; But regions, rather indistinctly vestured pits in ves terfield & Meylan, 1974; Miller, 1977) and con sel walls and fibre-tracheid walls were observed cerned families for which the presence of ves with the light microscope in the two woody tures was not constant (i.e. Proteaceae and species Cistus creticus L. and Cistus salvifolius Boraginaceae). In spite of these and other ex L. In order to establish the true nature of the amples of restricted taxonomic value at the vesturing, tangen tial surfaces were thoroughly family level cited by Bailey himself (1933), the cleaned with household bleach for one hour to occurrence of vestured pits remains of great remove any vessel contents or protoplasmic general taxonomic interest, mainly because debris from the pit chambers, washed in water, they help define and recognize large taxa like critical point dried, and sputter coated with Rubiaceae, Dipterocarpaceae and all truly Myr gold for scanning electron microscopy. talean families (Baas & Zweypfenning, 1979). Small, poorly branched, but distinct vestures, In recent classification systems (Hutchinson, attached to the edge of the apertures could fre 1959; Cronquist, 1968; Takhtajan, 1969; Dahl quently be observed in the vessel walls (Fig. 1 gren, 1975; and Thorne, 1976) Cistaceae are and 2). This conforms to Van Vliet's (1978) placed in Bixales, Violales or Cistales, varying type B form 3, although the vestures are a min greatly in delimitation according to the author. iature version of the massive vestures of this It is interesting to note that none of the pre type as described for Combretaceae by Van sumed relatives of the Cistaceae in these sys Vliet. Non-vestured pits are also of common tems of classification are known to have ves occurrence. Since almost all vessels in Cistus tured pits. Ochnaceae pro parte and Diptero are solitary and embedded in a ground tissue of carpaceae, which do have vestured pits, and fibre-tracheids, the pits pictured in Fig. I and 2 were listed in the same assembly (Parietales) as must be vessel to fibre-tracheid pits. Cistaceae by Bailey (1933) are currently re A superficial light microscopical study of garded to belong to other plant orders by most some other species of Cistus and of the genus authors. Recently Dahlgren transferred Cista Fumana represented in the Rijksherbarium ceae as well as Dipterocarpaceae and Sarcolae wood collection indicated the presence of ves naceae to his widely delimited Malvales. Inter tured pits of varying distinctness. In Helianthe estingly enough the important characters of mum apeninnimum, presence or absence of ves vestured pits, solitary vessels, ground tissue of ture could not be unambiguously established fibre-tracheids are shared by Cistaceae (p.p.), using the light microscope. A detailed scanning Dipterocarpaceae (p.p. : Monotoideae and Paka electron microscopical survey of all Cistaceae raimoideae, cf. De Zeeuw, 1977) and Sarco would be necessary to evaluate the diagnostic laenaceae. Wood anatomically these families and taxonomic value at and below the family differ rather strongly from the Malvales as un level in this group of woody to herbaceous derstood by most authors, but their possible plants. mutual affinity deserves further consideration.
* Rijksherbarium, P.O. Box 9514, 2300 RA Leiden, The Netherlands. **Botany Department, Hebrew University of Jerusalem, Israel.
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References Baas, P. & R.C.V.L Zweypfenning. 1979. Wood Hutchinson, 1. 1959. The families of flowering anatomy of the Lythraceae. Acta Bot. plants. I. Dicotyledons. Clarendon Press, Neerl. 28: 117-155. Oxford. Bailey,I.W. 1933. The cambium and its deriva Metcalfe, C.R. & L. Chalk. 1950. Anatomy of tive tissues. VIII. Structure, distribution the Dicotyledons. Clarendon Press, Ox and diagnostic significance of vestured ford. pits in Dicotyledons. 1. Am. Arbor. 14: Meylan, B.A. & B.G. Butterfield. 1974. Occur 259-273. rence of vestured pits in the vessels and Butterfield, B.G. & B.A. Meylan. 1974. Vestured fibres of New Zealand woods. New Zeal. vessel and fiber pits in Persoonia toru A. 1. Bot. 12: 3-18. Cunn. (Proteaceae). IAWA Bull. 1974/1: Miller, R.B. 1977. Vestured pits in Boragina 10-15. ceae.IAWABull. 1977/3: 43-48. Cronquist, A. 1968. The evolution and classifica Takhtajan, A. 1969. Flowering plants. Origin tion of flowering plants. Nelson, London. and dispersal. Oliver & Boyd, Edinburgh. Dahlgren, R. 1975. A system of classification Thome, R.F. 1976. A phylogenetic classifica of the Angiosperms to be used to demon tion of the Angiospermae. In: Hecht, strate the distribution of characters. Bot. Steere & Wallace (eds.), Evolutionary Bio Notiser 128: 119-147. logy 9: 35-106. -- 1980. A revised system of classification of Vliet, G.J.C.M. van. 1978. Vestured pits of the Angiosperms. Bot. 1. Linn. Soc. 80: Combretaceae and allied families. Acta 90-124. Bot. Neerl. 27: 273-285. Greguss, P. 1959. Holzanatomie der europii Zeeuw, C. de. 1977. Pakaraimoideae, Diptero ischen LaubhOlzer und Striiucher. Akade carpaceae of the Western hemisphere. III. miai Kiado, Budapest. Stem anatomy. Taxon 26: 368-380.
Fig. 1. Cistus salvifolia L. Vestured pit viewed from the vessel lumen side, x 13000. - Fig. 2. Cistus creticus L. Vestured pits viewed from the pit chamber side; note non-vestured pit (arrow), x 3400.
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