Wood Anatomy of Onagraceae: Additional Species and Concepts

Abstract

Wood anatomy of Epilobium colchicum subsp. colchicum, Fuchsia excorticata, and Hauya heydeana is described qualitatively and quantitatively. For the latter two species, large logs were available and wood portions from both inside and outside were analyzed. Although these three species offer no features new for Onagraceae, each adds features new for its respective genus. By means of numerical indices which are termed vulnerability and mesomorphy, respectively, values are presented to show the range in ecological characteristics of woods of the three species, .as well as of all Onagraceae studied earlier. Onagraceae show a wide range in these indices and probably form a good model of what use indices in families with a broad ecological range will demonstrate. Wood from inside of logs of Fuchsia excorticata and Hauya heydeana is more xeromorphic than wood from the periphery. In my monograph of wood anatomy of Onagraceae (Carlquist, 1975a), I attempted a sampling of woods based largely on availability of portions of suitable size. In any family in which herbs predominate, one is faced with arbitrary decisions as to whether some species which form little secondary xylem should be included. However, after the appearance of the monograph, Dr. Peter H. Raven placed at my disposal three wood samples with abundant secondary xylem for their respective genera, and otherwise of more than passing interest. MATERIALS AND METHODS Epilobium colchicum Alboff subsp. colchicum (sect. Chamaenerion) was collected by Dr. Peter H. Raven from a streambed near the Lagodekhi Hotel in eastern Georgia, U.S.S.R., and is unusually woody for an Epilobium. The species of Fuchsia that forms perhaps the largest trees in that genus (and perhaps also in the family) is F. excorticata (J. R. & G. Forst.) L. f. A section from the base of a -tree approximately 0.9 m in diameter (outline of section irregular) was supplied by the New Zealand Institute of Forestry. Dr. Dennis E. Breedlove's mesoamerican field work yielded a log, approximately 25 cm in diameter, of Hauya heydeana Donnell Smith. Because all the Hauya wood samples utilized in my earlier study were of H. elegans subsp. cornuta, material of the second species of this interesting genus was especially welcome. All three wood samples were dried. Methods of study were the same as those employed for dried samples in the earlier paper. Dr. Larry DeBuhr's work in preparing sections and macerations and in obtaining data is gratefully acknowledged. Because differences in wood anatomy were observed (Carlquist, 1975a) in samples of different diameter in Hauya elegans subsp. cornuta, both inner and outer portions of 'This study has been aided by a grant from the National Science Foundation, BMS 7307055-Al. The wood of Fuchsia excorticata was provided by Dr. E. J. Godley, D.S.I.R., Christchurch, New Zealand. 2 Claremont Graduate School, Pomona College, and Rancho Santa Ana Botanic Garden, Claremont, California 91711. ANN. MissouRi BOT. CARD. 64: 627-637. 1977. This content downloaded from 207.46.13.109 on Sun, 24 Apr 2016 06:46:10 UTC All use subject to http://about.jstor.org/terms 628 ANNALS OF THE MISSOURI BOTANICAL GARDEN [VOL. 64 I *~~~~~~~~~~~~~~~~~~~~~~~k FIGURES 1-4. Wlood sections of Epilo)ioon and Haiiya.-1-3. Epil)obioio colchicirn Alboff slubSp. colchicuin, Raven 26519 (NO) .-1. Transection; parenchyma blands not shown in this photograph.-2. Tangential section; rays few, inconspicuous.-3. Portion of vessel awall from tangential section.-4. Hauya heydeana Donnell Smith, Breedlove 15653 (MO). Radial section of ray cells showing nature of walls and starch grains embedded in dark-staining amorphous materials. [Magnification indicated by photograph of stage micrometer enlarged at same scale as applicable photomicrographs. Figs. 1-2, scale above Fig. 2 (finest divisions 10 Binm). Figs. 3-4, scale above Fig. 4 (divisions = 10 um).] This content downloaded from 207.46.13.109 on Sun, 24 Apr 2016 06:46:10 UTC All use subject to http://about.jstor.org/terms 1977] CARLQUIST-WOOD ANATOMY OF ONAGRACEAE 629 the logs of Fuchsia excorticata and Hauya heydeana were studied. Quantitative data for both portions are reported below. Qualitative features of inner and outer portions are the same unless otherwise mentioned. ANATOMICAL DESCRIPTIONS Epilobium colchicum subsp. colchicum, Raven 26519 (MO), Figs. 1-3. Growth rings present as parenchyma bands that are discontinuous in places around the stem. Mean vessel diameter, 50 Km; mean vessel element length, 184 ,um. Vessels mostly solitary (Fig. 1); if grouped, in radial chains or multiples; mean number of vessels per group 1.36. Mean number of vessels per mm2 of transection 38.1. Perforation plates simple. Lateral wall pitting of vessels basically alternate, appearing somewhat scalariform because pits are laterally elongate (Fig. 3). Pits conspicuously vestured (Fig. 3). Mean libriform fiber length 277 Km. Mean libriform fiber wall thickness 1.6 jum. Libriform fiber walls not gelatinous; pits simple. Axial parenchyma in the form of bands, with also a few vasicentric cells forming strands of one to three cells. Bands of axial parenchyma probably contain interxylary phloem, but determination uncertain because of lack of liquid preservation. Multiseriate rays more frequent than uniseriates, but both inconspicuous (Fig. 2) because upright cells predominate in multiseriates, with only a few square and procumbent cells. Uniseriate rays consist of upright cells only. Mean height of multiseriate rays 567 Km; uniseriates, 84 Km. Ray cells thin to moderately thick, the latter sometimes with bordered pits. No crystals observed. Amorphous deposits of dark-staining materials in some ray cells (Fig. 1). Wood not storied. Fuchsia excorticata, Figs. 5-8. Growth rings inconspicuous in inner wood (Fig. 5), with narrower vessels in latewood, wider vessels in earlywood. Growth rings not evident in outer wood. Mean vessel diameter 73 um in outer wood, 63 km in inner wood. Mean vessel element length 325 .km in outer wood, 259 ytm in inner wood. Vessels solitary or in multiples (Fig. 5), averaging 1.52 per group. in outer wood, 1.76 per group in inner wood. Mean number of vessels per mm2 of transection 32 in outer wood, 57 in inner wood. Perforation plates simple. Tyloses present in vessels, numerous, thin-walled (Fig. 6, right). Lateral wall pitting of vessels (Fig. 8) consists of alternate pits, angular and rhomboidal in outline or laterally elongate. Pits conspicuously vestured. Mean libriform fiber length 598 tm in outer wood, 562 jum in inner wood. Libriform fiber wall thickness 2.5 ytm in outer wood, 2.9 /im in inner wood. Libriform fiber walls not noticeably gelatinous. Libriform fibers prominently septate (Fig. 7). Extremely minute vestiges of borders observed on pits of some libriform fibers (Fig. 7). Interxylary phloem absent. Axial parenchyma scanty vasicentric; strands consisting of three to five cells per strand. Rays predominantly multiseriate (Fig. 6); uniseriates infrequent, virtually absent in inner wood. Mean multiseriate ray height 755 um in outer wood, 494 tm in inner wood; uniseriates (outer wood), 224 tm. Multiseriates composed of upright, square and procumbent cells. Uniseriates composed wholly of erect cells. No crystals observed. A few ray cells with dark-staining contents (Fig. 6). Wood not storied. This content downloaded from 207.46.13.109 on Sun, 24 Apr 2016 06:46:10 UTC All use subject to http://about.jstor.org/terms 630 ANNALS OF THE MISSOURI BOTANICAL GARDEN [VOL. 64