Taxonomic significance of leaves in family Aizoaceae

Abstract

Aizoaceae is one of the most important and widespread succulent plant families in both tropical/subtropical regions and arid zones. In this study, 27 species were collected from various floristic regions in Egypt, Kingdom of Saudi Arabia and cactus farms (Kalupia - Egypt). The morphological characteristics of every taxon were recorded. The important morphological features included: the number of leaves per plant; leaf types; leaf position (cauline or radical; the latter indicates leaves arising from, or near, the roots); leaf arrangement; petiolate or sessile leaves; leaf sheath present or absent; leaf shape; leaf margin; leaf tip; presence of leaf 'window area'; leaf texture; and presence of white or dark miniscule dots (white miniscule dots from calcium carbonate and dark miniscule dots from tannin sacs). The investigated anatomical features were as follows: shape of the transverse section; the type of epidermal cells; the presence of large epidermal cells (bladder cells); presence of papilla and simple hairs; presence of tannin sacs; shapes of calcium oxalate crystals; shape of the xylem vessels; and the presence of Kranz unit (the unit that constitutes the vascular bundle/s, parenchyma sheath, and surrounding mesophyll) or collenchyma sheath. All data were recorded in a data matrix (as either text or numerical data), which was used to construct the identification key and phylogeny tree using a multi-variate statistical package. The results of our analysis may open the possibility of using the morphological and anatomical features of leaves to distinguish between the subfamilies, genera, and species of Aizoaceae.

Keywords: Aizoaceae; Leaf anatomy; Leaf morphology; Numerical analyses; Plant taxonomy.

Plate 1

included figures 1–16, which showing some important morphological features: 1- Zaleya pentandra, 2- Lithops aucampiae, 3- Trianthema portulacastrum, 4- Aptenia cordifolia, 5- Aizoon canariense, 6- Faucaria bosscheana, 7- Carpobrotus acinaciformis, 8- Fenestraria rhopalophylla, 9- Faucaria tuberculosa, 10- Glottiphyllum linguiforme, 11- Delosperma echinatum, 12-Aloinopsis malherbei, 13- Drosanthemum floribundum, 14- Oscularia deltoids, 15- Lampranthus aureus and 16- Tanquana prismatica.

Plate 2

included Figures 17–24, which showing some important anatomical features: 17- Lithops pseudotruncatella(40X), 18- Sesuvium portulacastrum(100X),19- Aloinopsis malherbei(100X), 20- Lithops aucampiae(650X), 21- Aptenia cordifolia(Epidermal peel-100X), 22– Aptenia cordifolia (transvers section100X), 23– Trianthema portulacastrum(100X), 24- Lithops pseudotruncatella(40X). Abbreviations: R = ridge, F = furrow, u = united cells, e = epidermis, m = mesophyll, me = multiplicative epidermis, k = kranz unite, dc = druses crystals, ie = internal epidermis.

Plate 3

included Figures 25–32, which showing some important anatomical features:25- Mesembryanthemum nodiflorum(40X), 26- Lampranthus aureus(100X), 27- Faucaria tuberculosa(100X), 28- Carpobrotus edulis(100X), 29- Tanquana prismatica(100X), 30- Lithops pseudotruncatella(100X), 31- Carpobrotus edulis(100X), 32– Trianthema portulacastrum(100X). Abbreviations: p = papilla, sc = storage cells, rc = raphides crystals, vb = vascular bundles, ts = tannin sacs, xv = xylem vessels, cs = collenchyma sheath.

Fig. 33

Phylogeny tree for 27 taxa of Aizoaceae depending on 16 morphological features and 20 anatomical features.