Anatomical Support for the Taxonomy of Calophyllum (Guttiferae) in Panama

Abstract

Leaves of eight species of Calophyllum growing in Panama were sectioned and characterized anatomically. A number of characters seemed useful in clarifying the taxonomy and evolution of the genus. Apparently useful characters at the species level include midrib shape, primary vein V angle, presence or absence of transcurrent ducts, and presence or absence of a hypodermis. The species C. nubicola D'Arcy & Keating is described. Taxonomic relationships among the Panamanian species have been clarified. Old World species introduced into Panama can be distinguished anatomically, but they are not separable statistically as a group from New World species examined. The genus Calophyllum comprises well over 100 species of New and Old World flowering plants. In preparing the treatment of the genus for the Flora of Panama, species were difficult to separate on herbarium morphological evidence, so anatomical studies of leaves were undertaken. Such studies had been used to good advantage in the Guttiferae by Vesque (1889, 1893), Schofield (1968), and Stevens (1974, 1976). Smith & Darwin (1974) discussed anatomy of the fruit, but only Vesque had touched on plants of the New World. Although Vesque established three sections for Old World species of Calophyllum, he did not classify the New World species into sections. Our anatomical studies summarized in Table 1 tended to confirm tenuous conclusions drawn from study of herbarium sheets, and they suggested changes that might not otherwise have been made, namely, recognition of a new species and separation of Calophyllum rekoi and Panamanian plants formerly known as C. longifolium from C. brasiliense. They also showed the anatomical basis for the leaf ribs which are a useful taxonomic character. A less satisfactory conclusion is that two specimens studied in detail cannot be assigned to any of the known species from Panama, and the herbarium material is insufficient for description of new species. While it is possible that these species have already been described based on material from other countries, our investigations suggested no likely candidates among the relatively few species that have been described from the New World. These results suggest that further realignments will be required, but these possibilities could not be pursued within the limitations of this study. MATERIALS AND METHODS Following careful study of material available from several herbaria (A, F, GH, MO, DUKE, PMA, SCZ, US) a number of elements were selected for ' We acknowledge support from National Science Foundation Grant DEB77-04300 (W. G. D'Arcy, Principal Investigator) and the Research and Projects Office, Southern Illinois University. 2 Missouri Botanical Garden, Post Office Box 299, St. Louis, Missouri 63166. 3 Department of Biological Sciences, Southern Illinois University, Edwardsville, Illinois 62026. ANN. Missoum BOT. GARD. 66: 557-571. 1979. 0026-6493/79/0557-0571/$1.65/0 This content downloaded from 157.55.39.177 on Tue, 15 Nov 2016 03:59:00 UTC All use subject to http://about.jstor.org/terms 558 ANNALS OF THE MISSOURI BOTANICAL GARDEN [VOL. 66 anatomical study. This selection included specimens of plants believed to be native to the neotropics, and two species known to have been introduced into cultivation from the Old World. One of these Old World species, C. inophyllum, has been studied anatomically by several other workers so this species provides a reference of our work to that of others. Specimens of leaves of eight species of Calophyllum were removed from nine herbarium collections (see Table 1) and restored using Aerosol OT (Ayensu, 1967) at 450C for one week. Two pieces from approximately the center of each leaf were selected and oriented to produce transverse sections of the midrib and transverse sections of the parallel secondary veins. Following restoration, the specimens were fixed in 50% formalin-propiono-alcohol, dehydrated in a tertiary butyl alcohol series (Johansen, 1940), embedded in Paraplast and sectioned at 10 lim. The sections were stained in Safranin O-Fast Green FCF and photographed at 100X magnification. Drawings of the midrib areas were made using a microprojector. Hand sections were made of leaves of many other available specimens to confirm results drawn from paraffin sections. In addition counts of vein frequency were made of all specimens available.