Comparative leaf morphology and anatomy of some neotropical Philodendron Schott (Araceae) species

Abstract

aBstract. A comparative morphological and anatomical study on the petioles and lamina of 22 taxa (species, subspecies and cultivars) of the genus Philodendron (subgenera Meconostigma, Pteromischum and Philodendron) has been made in order to investigate interspecific differences which may be useful in species identification. All species have bifacial leaves with petioles, amphistomatic with a strongly reduced density of stomata on the adaxial leaf surface. The species differ in the size and shape of their epidermal cells, the distribution and types of stomata and cuticle ornamentation in the lamina, thickness of epicuticular layer, presence or absence of hypodermis, structure of spongy mesophyll, thickness of palisade and spongy mesophyll layers, as well as types of raphides, and in the structure and forms of petioles. A combination of these characters may be useful in species identification. This study shows that there is some variation in petiole and leaf morphological and anatomical characters among the 22 taxa of Philodendron. However, many characters are present in all of them and may be typical of the genus. The study revealed several detailed interesting epidermal and anatomical features that have not previously been reported in the genus.

Calcium oxalate crystals in some Philodendron Schott (Araceae) species

“…Raphides were not observed in P. crassinervium, P. hederaceum var. hederaceum or P. erubescens (Table 3), similarly as it was in an earlier study by KliMKo et al (2014). croat (1997) stated that in petioles of Philo dendron subgenus Philodendron narrow raphide cells occur occasionally and are oriented across aerenchyma partitions with ends pointing into air cavities, or with cells randomly oriented.…”

“…Results presented in this study based on new leaves in relation to a paper by KliMKo et al (2014) supply new data concerning the occurrence of raphides in six species: P. melanochrysum, P. ornatum, P. bi pennifolium, P. imbe, P. martianum and P. lacerum (Table 3). Raphides were not observed in P. crassinervium, P. hederaceum var.…”

“…Since then, various systematic accounts of raphides have been published (solereder & Mayer 1928, Franceschi & horner 1980, genua & hillson 1985, Keating 2003, 2004a. There are very few literature reports on calcium oxalate crystal in species of Philodendron (croat 1997, Keating 2003, 2004a, KliMKo et al 2014. Calcium oxalate exists in two chemical forms, the monohydrate and the dihydrate, and both of these are found in plants.…”

Phylogeny and diversification history of the large Neotropical genus Philodendron (Araceae): Accelerated speciation in a lineage dominated by epiphytes

“…(, ) documented some morphological similarities supporting a closer phylogenetic relationship between Adelonema and subgenus Pteromischum (e.g., anisophyllous sympodial growth with several or many leaves per stem article, absent or highly inconspicuous cataphylls, and sheathing petioles). However, apart from the different life forms (species of subgenus Pteromischum are vines while Adelonema species are strictly terrestrial herbs), floral characters used in the taxonomic circumscription of the genus Philodendron (e.g., shape and vascularization patterns in the stamens, style morphology, and number of ovules per locule; Grayum, ) as well as certain anatomical characters (e.g., presence of three types of raphide cells; Klimko et al., ) are evidence for a closer relationship of Philodendron subgenus Pteromischum to the other two subgenera of the genus Philodendron than to Adelonema .…”

“…The monophyly of Philodendron is strongly supported by our results. Although there is no single morphological feature that unambiguously distinguishes Philodendron from closely related genera, the combination of the following characters supports its monophyly: plants usually climbing or epiphytic (if terrestrial herbs, adult plants with conspicuous cataphylls and petiolar sheath much reduced); inflorescences secreting resin at anthesis, either from the adaxial canals of the spathe or from the spadix, rarely from both; spadix with distinct sterile staminate zone between pistillate zone and fertile staminate zone; endothecium nearly always with cell wall thickenings; female flowers without staminodes; ovary with two to many completely separate locules, with axile to basal placentation; and ovules one to many per locule, usually hemiorthotropous, rarely hemianatropous (Grayum, ; Croat, ; Klimko et al., ).…”