Changes in cambial activity are related to precipitation patterns in four tropical hardwood species grown in Indonesia.

PREMISE: Cambial activity in some tropical trees varies intra-annually, with the formation of xylem rings. Identification of the climatic factors that regulate cambial activity is important for understanding the growth of such species. We analyzed the relationship between climatic factors and cambial activity in four tropical hardwoods, Acacia mangium, Tectona grandis, Eucalyptus urophylla, and Neolamarckia cadamba in Yogyakarta, Java Island, Indonesia, which has a rainy season (November-June) and a dry season (July-October). METHODS: Small blocks containing phloem, cambium, and xylem were collected from main stems in January 2014, October 2015 and October 2016, and examined with light microscopy for cambial cell division, fusiform cambial cells, and expanding xylem cells as evidence of cambial activity. RESULTS: During the rainy season, when precipitation was high, cambium was active. By contrast, during the dry season in 2015, when there was no precipitation, cambium was dormant. However, in October 2016, during the so-called dry season, cambium was active, cell division was conspicuous, and a new xylem ring formation was initiated. The difference in cambial activity appeared to be related to an unusual pattern of precipitation during the typically dry months, from July to October, in 2016. CONCLUSIONS: Our results indicate that low or absent precipitation for 3 to 4 months induces cessation of cambial activity and temporal periodicity of wood formation in the four species studied. By contrast, in the event of continuing precipitation, cambial activity in the same trees may continue throughout the year. The frequency pattern of precipitation appears to be an important determinant of wood formation in tropical trees.

Stochastic modelling of tree architecture and biomass allocation: application to teak (Tectona grandis L. f.), a tree species with polycyclic growth and leaf neoformation.

Background and aims: For a given genotype, the observed variability of tree forms results from the stochasticity of meristem functioning and from changing and heterogeneous environmental factors affecting biomass formation and allocation. In response to climate change, trees adapt their architecture by adjusting growth processes such as pre- and neoformation, as well as polycyclic growth. This is the case for the teak tree. The aim of this work was to adapt the plant model, GreenLab, in order to take into consideration both these processes using existing data on this tree species. Methods: This work adopted GreenLab formalism based on source-sink relationships at organ level that drive biomass production and partitioning within the whole plant over time. The stochastic aspect of phytomer production can be modelled by a Bernoulli process. The teak model was designed, parameterized and analysed using the architectural data from 2- to 5-year-old teak trees in open field stands. Key results: Growth and development parameters were identified, fitting the observed compound organic series with the theoretical series, using generalized least squares methods. Phytomer distributions of growth units and branching pattern varied depending on their axis category, i.e. their physiological age. These emerging properties were in accordance with the observed growth patterns and biomass allocation dynamics during a growing season marked by a short dry season. Conclusions: Annual growth patterns observed on teak, including shoot pre- and neoformation and polycyclism, were reproduced by the new version of the GreenLab model. However, further updating is discussed in order to ensure better consideration of radial variation in basic specific gravity of wood. Such upgrading of the model will enable teak ideotypes to be defined for improving wood production in terms of both volume and quality.

The CYCLOIDEA-RADIALIS module regulates petal shape and pigmentation, leading to bilateral corolla symmetry in Torenia fournieri (Linderniaceae).

The diverse pigmentation patterns of flower corollas probably result from pollinator-mediated selection. Previous studies demonstrated that R2R3-MYB factors may have been recruited in the regulation of corolla pigmentation. However, how R2R3-MYBs became so diverse in their regulation of different pigmentation patterns remains unclear. Here, we studied a Lamiales species, Torenia fournieri, which has elaborate zygomorphic flowers with dorsal-ventral asymmetries in corolla pigmentation. We found recent gene duplication events in CYCLOIDEA-like (CYC-like) and RADIALIS-like (RAD-like) genes, and functionally analyzed three dorsal-specific expression factors: TfCYC1, TfCYC2, and TfRAD1. We found that the CYC-RAD module coordinates petal shape and corolla pigmentation, as ectopic expression of TfCYC2 or TfRAD1 disrupted the asymmetric corolla pigmentation pattern and produced strongly dorsalized flowers. Dorsal petal identity was lost when TfCYC2 was down-regulated or when TfRAD1 was knocked out. In T. fournieri, the diversified CYC and RAD genes have evolved regulatory loops, and TfCYC2 binds directly to the regulatory regions of an R2R3-MYB factor gene, TfMYB1, which might lead to its asymmetric expression and ultimately establish the asymmetric pigmentation pattern. These findings support the existence of a regulatory module that integrates dorsal-ventral patterning and asymmetric corolla pigmentation in T. fournieri.

Repeated and diverse losses of corolla bilateral symmetry in the Lamiaceae.

Background and Aims: Independent evolution of derived complex characters provides a unique opportunity to assess whether and how similar genetic changes correlate with morphological convergence. Bilaterally symmetrical corollas have evolved multiple times independently from radially symmetrical ancestors and likely represent adaptations to attract specific pollinators. On the other hand, losses of bilateral corolla symmetry have occurred sporadically in various groups, due to either modification of bilaterally symmetrical corollas in late development or early establishment of radial symmetry. Methods: This study integrated phylogenetic, scanning electron microscopy (SEM)-based morphological, and gene expression approaches to assess the possible mechanisms underlying independent evolutionary losses of corolla bilateral symmetry. Key Results: This work compared three species of Lamiaceae having radially symmetrical mature corollas with a representative sister taxon having bilaterally symmetrical corollas and found that each reaches radial symmetry in a different way. Higher core Lamiales share a common duplication in the CYCLOIDEA (CYC ) 2 gene lineage and show conserved and asymmetrical expression of CYC2 clade and RAD genes along the adaxial-abaxial floral axis in species having bilateral corolla symmetry. In Lycopus americanus , the development and expression pattern of La-CYC2A and La-CYC2B are similar to those of their bilaterally symmetrical relatives, whereas the loss of La-RAD expression correlates with a late switch to radial corolla symmetry. In Mentha longifolia , late radial symmetry may be explained by the loss of Ml-CYC2A , and by altered expression of two Ml-CYC2B and Ml-RAD genes . Finally, expanded expression of Cc-CYC2A and Cc-RAD strongly correlates with the early development of radially symmetrical corollas in Callicarpa cathayana . Conclusions: Repeated losses of mature corolla bilateral symmetry in Lamiaceae are not uncommon, and may be achieved by distinct mechanisms and various changes to symmetry genes, including the loss of a CYC2 clade gene from the genome, and/or contraction, expansion or alteration of CYC2 clade and RAD -like gene expression.

Morphological and phylogenetic investigations for several cryptic ant-plants found in Callicarpa (Lamiaceae) from Borneo.

A tropical small tree, Callicarpa saccata, is known to have a symbiotic relationship with ants. It has sac-like structures at the base of the leaves that are inhabited by ants. No other species has been determined to be a myrmecophyte among the ca. 140 species of this genus. However, our recent field investigation discovered that two other species on Borneo (C. barbata and C. teneriflora) have hollow stems, which seem to be inhabited by ants. We observed the morphological features of these species in relation to their usage by ants, and became convinced that they are mymecophytic species. The molecular phylogenetic analyses using ITS and chloroplast regions suggest that C. saccata and C. teneriflora are closely related, but the differences in the myrmecophytic features of these species should be noted.

[Anatomical structures of Coleus forskohlii transplanted in Tongcheng].

OBJECTIVE: To investigate the vegetative tissues of Coleus forskohlii cultivated in Tongcheng, Hubei Province, and to provide useful information for its planting. METHODS: The root, stem, leaf and enlarged rhizome of Coleus forskohlii were subject to routine paraffin section and staining with safranin and fast green FCF solution before examination by light microscopy. RESULTS: The secondary tissue was well developed in root, and stem showed a higher percentage of cortex and pitch, and 4 large vascular bundles. Leaf epidermis was covered by lots of trichomes, including glandular hairs, glandular scale and linear non-glandular hairs. Mesophyll tissue was poorly differentiated to palisade and spongy tissues. Enlarged rhizome was the same as normal dicotyledons plants. CONCLUSION: Enlarged rhizome, unconspicuous root tuber and poorly differentiated leaf mesophyll cells are 3 main different features of Coleus forskohlii transplanted in Tongcheng. These results provide scientific basis for formulating quality standards, further cultivation and utilization of the plant.

Pair-flowered cymes in the Lamiales: structure, distribution and origin.

BACKGROUND AND AIMS: In the Lamiales, indeterminate thyrses (made up of axillary cymes) represent a significant inflorescence type. However, it has been largely overlooked that there occur two types of cymes: (1) ordinary cymes, and (2) 'pair-flowered cymes' (PFCs), with a flower pair (terminal and front flower) topping each cyme unit. PFCs are unique to the Lamiales and their distribution, origin and phylogeny are not well understood. METHODS: The Lamiales are screened as to the occurrence of PFCs, ordinary cymes and single flowers (constituting racemic inflorescences). KEY RESULTS: PFCs are shown to exhibit a considerable morphological and developmental diversity and are documented to occur in four neighbouring taxa of Lamiales: Calceolariaceae, Sanango, Gesneriaceae and Plantaginaceae. They are omnipresent in the Calceolariaceae and almost so in the Gesneriaceae. In the Plantaginaceae, PFCs are restricted to the small sister tribes Russelieae and Cheloneae (while the large remainder has single flowers in the leaf/bract axils; ordinary cymes do not occur). Regarding the origin of PFCs, the inflorescences of the genus Peltanthera (unplaced as to family; sister to Calceolariaceae, Sanango and Gesneriaceae in most molecular phylogenies) support the idea that PFCs have originated from paniculate systems, with the front-flowers representing remnant flowers. CONCLUSIONS: From the exclusive occurrence of PFCs in the Lamiales and the proximity of the respective taxa in molecular phylogenies it may be expected that PFCs have originated once, representing a synapomorphy for this group of taxa and fading out within the Plantaginaceae. However, molecular evidence is ambiguous. Depending on the position of Peltanthera (depending in turn on the kind and number of genes and taxa analysed) a single, a double (the most probable scenario) or a triple origin appears conceivable.

Taxonomic studies based on leaf epidermal microanatomy using high-resolution microscopy in Lamiaceous species and their antimicrobial effects.

The knowledge of essential oil antimicrobial activity of Lamiaceous species is assessed to describe its effects. The comprehensive foliar trichomes and stomatal morphology of the leaves of essential oil-bearing plants from the family Lamiaceae revealed diverse antimicrobial properties. The aim of this study was to investigate the foliar anatomical traits of 19 Lamiaceous taxa belonging to different tribes using light and scanning electron microscopy to correctly diagnose the species. The microanatomy of the foliar epidermis, trichomes diversity, and the stomatal apertural complex was visualized. Quantitative measurements were noted to describe the variations and the qualitative aspects for example, polygonal shape epidermal cells were examined. The stomatal aperture of four types and trichomes appendages both non-glandular and glandular was identified. Significant variation was found in both quantitative and qualitative traits, including unique ornamentation on the trichomes. The taxonomic key was constructed for accurate identification using qualitative morpho-structural traits. The outcomes of this research explored taxonomically to accurately identify the Lamiaceous species using anatomical characters. This study will provide provides the ecological adaptation linked to evolutionary traits of leaf surfaces that evolve with time to adapt the harsh environmental conditions. RESEARCH HIGHLIGHTS: Investigated foliar anatomical traits of 19 Lamiaceous species The anatomy and antimicrobial activity of essential oil yielding Lamiaceae species. SEM revealed diverse aspects including peculiar sculptured trichomes Microscopic identification of different stomatal complex.

An unusual form of reaction wood in Koromiko [Hebe salicifolia G. Forst. (Pennell)], a southern hemisphere angiosperm.

Koromiko [Hebe salicifolia G. Forst. (Pennell)] is a woody angiosperm native to New Zealand and Chile. Hebe spp. belong to the otherwise herbaceous family Plantaginaceae in the order Lamiales. Reaction wood exerting expansional forces was found on the lower side of leaning H. salicifolia stems. Such reaction wood is atypical for angiosperms, which commonly form contracting reaction wood on the upper side of leaning stems. Reaction wood typical for angiosperms is formed by species in other families in the order Lamiales. This suggests that the form of reaction wood is specific to the family level. Functionally the reaction wood of H. salicifolia is similar to that found in gymnosperms, which both act by pushing. However, their chemical, anatomical and physical characteristics are different. Typical features of reaction wood present in gymnosperms such as high density, thick-walled rounded cells and the presence of (1 → 4)-ß-galactan in the secondary cell wall layer are absent in H. salicifolia reaction wood. Reaction wood of H. salicifolia varies from normal wood in having a higher microfibril angle, which is likely to determine the direction of generated maturation stresses.

Morpho-Anatomical Study And Botanical Identification of Pogostemon auricularius (L.) Hassk. (Lamiaceae).

Pogostemon Desf. includes a wide range of taxa found in subtropical and tropical areas. Few works, however, have studied microanatomical characteristics of Pogostemon species and as yet identified features of Pogostemon auricularius (L.) Hassk. Thus, in this paper, we examined the taxonomic implications of root, stem and leaf morphology for species P. auricularius collected from Quang Tri Province. Light microscopy was mainly used in our study. Qualitative characters like stem quadrangular, hirsute; leaves opposite, ovate, margin serrulate; calyx campanulate; corolla small with separate equal lobes have been found in P. auricularius. Epidermal anatomy on the aerial parts of the species like epidermal cell shape, anticlinal walls, trichomes types, stomata types and calcium oxalate crystals types were examined as well. Quantitative characters like the length and width of leaf blade and inflorescence; the size of oil droplet, stomata and calcium oxalate crystals measured provided taxonomic significance. Based on identifying morphological characteristics of P. auricularius, we aimed to contribute to the taxonomic investigation into the genus Pogostemon and give relative morphological and microanatomical features compared with other taxa.

Authentication of the therapeutic Lamiaceae taxa by using pollen traits observed under scanning electron microscopy.

Herbal medicines are gaining popularity worldwide for human healthcare because of their therapeutic potential. However, adulteration and use of unauthentic raw herbals as substitutes have become a major issue for the local communities and industry for reasons of safety and efficacy. Therefore, the authentication of medicinal plants before their use in herbal medicines is a need of time. Hence, the present study was designed with an aim, to authenticate the therapeutic Lamiaceous taxa by using pollen traits observed under scanning electron microscopy. Pollen micro-morphological studies solve the problem through discrimination and correct identification of the Lamiaceae species from the adulterants. Based on pollen features, Lamiaceae were further divided into two sub-families Lamioideae (tricolpate) and Nepetoideae (hexa-colpate). The pollen grains of Lamioideae were found as small to medium-sized, tricolpate, radially/bilateral symmetrical, sub-spheroidal and oblate shape. Besides, exine patterns bireticulate, reticulate and micro-reticulate, colpus surface sculpturing as psilate, gemmate, scabrate, and verrucate have also been reported. A significant variation was found in the pattern of the reticulum, thickness, and the number of secondary lumina per primary lumen. Similarly, Nepetoideae has a hexa zono-colpate pollen but tri and tetra zono-colpate pollen have also been observed. Hence, this study contributes to the authentication and correct identification of medicinally important Lamiaceae taxa by using scanning electron microscopic techniques and can help to solve the adulteration problem. Highlights Authentication of medicinally important Lamiceous taxa was carried out through scanning electron microscopic techniques. Chemotaxonomic characterization was used for the accurate identification of the therapeutic taxa. The medicinal, palynological and phytochemical significance of Lamiaceae taxa were evaluated. A significant variation was seen in the palynological traits that help in the determination and authentication of the therapeutic Lamiaceous species. Based on the chemotaxonomic characterization, our study can help to solve the adulteration problem for the reason of safety and efficacy.

Foliar micromorphology of selected medicinal Lamiaceae taxa and their taxonomic implication using scanning electron microscopy.

In this research, 25 medicinally used Lamiaceae species belonging to 20 genera have been studied and identified for the nine disorders. We used scanning electron microscopy (SEM) for qualitative and quantitative morphological character identification. The micromorphological characters observed here were important for distinguishing the studied taxa. The highest medicinal values were reported for Vitex negundo and Scutellaria baicalensis for all considered categories except urinary and otorhinolaryngology disorders. The foliar epidermal anatomical characteristics revealed that the micromorphological features of the Lamiaceae species provide taxonomically significant and accurate identification information to delimitate the family species. Moreover, we focused on both qualitative (epidermal cell shape, stomata type, stomatal pore shape, subsidiary cell shape, glandular trichomes, and non-glandular trichome shape) as well as quantitative features (epidermal cell size, stomata size, stomatal pore size, subsidiary cell size, and trichomes size). The trichomes diversity was different in most species' on adaxial and abaxial surfaces. In most species, anomocytic stomata were observed, but other types such as diacytic, paracytic, and tetracytic type stomata were also examined. The diverse pattern of anatomical characters suggests that the studied taxa provide insight evidence for the taxonomic observation of the Traditional Chinese Medicinal plants from the Lamiaceae. This work sets an avenue for future research and taxonomic exploration of medicinal flora through microscopic investigations. RESEARCH HIGHLIGHTS: This research offers a thorough microscopic identification of the family Lamiaceae. Taxonomic information on the trichome characters and types for the accurate authentication. Qualitative and quantitative characterization of 25 medicinally used Lamiaceae taxa.

Marcescent corollas as functional structures: effects on the fecundity of two insect-pollinated plants.

BACKGROUND AND AIMS: Persistence of withered corollas after anthesis ('corolla marcescence') is widespread in angiosperms, yet its functional significance does not seem to have been explored for any species. This note reports the results of experiments assessing the fecundity effects of marcescent corollas in two southern Spanish insect-pollinated plants, Lavandula latifolia (Lamiaceae) and Viola cazorlensis (Violaceae). METHODS: The effect of marcescent corollas on seed production was evaluated experimentally on wild-growing plants. Newly open flowers were randomly assigned to either control or treatment groups in experimental plants. After anthesis, withered corollas of treatment flowers were removed and those in control flowers were left in place. Fruits produced by treatment and control flowers were collected shortly before dehiscence and the number of seeds counted. KEY RESULTS: In V. cazorlensis, removal of withered corollas had no effect on percentage of fruit set, but mean seeds per fruit increased from 9·5 to 11·4. In L. latifolia, corolla removal had no effect on the number of seeds per fruit, but reduced the proportion of flowers ripening fruit from 60 % to 40 %. The detrimental effect of corolla removal on L. latifolia fecundity resulted from the drastic increase in fruit infestation by seed-predatory cecidomyiid larvae, which occurred in 4 % and 34 % of control and treatment fruits, respectively. CONCLUSIONS: Because of their potential effects on plant fecundity, marcescent corollas should not be dismissed a priori as biologically irrelevant leftovers from past floral functions. The simplicity of the experimental layout required to test for short-term fecundity effects of corolla marcescence should help to achieve a better understanding of the ecological and evolutionary correlates of this widespread but poorly understood trait.

Anatomy, micromorphology, and histochemistry of leaves and stems of Cantinoa althaeifolia (Lamiaceae).

This article enumerates the detailed anatomy of Cantinoa althaeifolia (Lamiaceae) illustrated with light and scanning electron microscopy images. The anatomical markers include the presence of branched nonglandular trichomes and capitate, peltate, and clavate types of glandular trichomes; prismatic crystals on the leaf and stem surfaces; and oil droplets in the leaf mesophyll. Histochemical tests and EDS analyses were performed in order to detect the composition of certain cells and their contents. The key findings of the present study can contribute to the taxonomy, species identification, and quality control of Cantinoa althaeifolia.

Comparative pollen and foliar micromorphological studies using light microscopy and scanning electron microscopy of some selected species of Lamiaceae from Alpine Zone of Deosai Plateau, Western Himalayas.

The study was conducted to highlight a detailed account of morphology of pollen chosen species of Lamiaceae through scanning electron microscopy, and the anatomical characteristics of leaf epidermis of seven species using simple light microscopy. In results, Anisomeles indica and Otostegia aucheri belong to subfamily Lamioideae because it has tricolpate pollen while the rest eight species belong to subfamily Nepetoideae (hexacolpate pollen). The exine sculpturing of pollen of studied species was found to be reticulate. In the family Lamiaceae, four kinds of stomata were found anomocytic, anisocytic, diacytic, and actinocytic, respectively. The cell wall patterns of epidermal cells were irregular or polygonal with straight or undulate walls. It was noted that the variety of the epidermal trichomes seems of taxonomically important for the identification of species of Lamiaceae. Both nonglandular and glandular trichomes were analyzed. The nonglandular trichomes were characterized with long, thin, and pointed apical unicellular cells. The nonglandular trichomes were A-shaped in Thymus linearis. In Perovskia abrotanoides, stellate glandular trichomes were observed whereas in A. indica and Mentha royleana both glandular and nonglandular trichomes were found. In A. indica, the nonglandular trichomes were sessile and peltate in M. royleana. For the first time in this study, pollen and foliar micromorphological features of selected species of this area are carried out. These taxonomic characters were found to be important in discrimination of species from each other. In future, the detailed study with comprehensive morphology coupled with other important characters is required for delimitation of taxa at various levels.

Flower nectar trichome structure of carnivorous plants from the genus butterworts Pinguicula L. (Lentibulariaceae).

Pinguicula (Lentibulariaceae) is a genus comprising around 96 species of herbaceous, carnivorous plants, which are extremely diverse in flower size, colour and spur length and structure as well as pollination strategy. In Pinguicula, nectar is formed in the flower spur; however, there is a gap in the knowledge about the nectary trichome structure in this genus. Our aim was to compare the nectary trichome structure of various Pinguicula species in order to determine whether there are any differences among the species in this genus. The taxa that were sampled were Pinguicula moctezumae, P. moranensis, P. rectifolia, P. emarginata and P. esseriana. We used light microscopy, histochemistry, scanning and transmission electron microscopy to address those aims. We show a conservative nectary trichome structure and spur anatomy in various Mexican Pinguicula species. The gross structural similarities between the examined species were the spur anatomy, the occurrence of papillae, the architecture of the nectary trichomes and the ultrastructure characters of the trichome cells. However, there were some differences in the spur length, the size of spur trichomes, the occurrence of starch grains in the spur parenchyma and the occurrence of cell wall ingrowths in the terminal cells of the nectary trichomes. Similar nectary capitate trichomes, as are described here, were recorded in the spurs of species from other Lentibulariaceae genera. There are many ultrastructural similarities between the cells of nectary trichomes in Pinguicula and Utricularia.

Comparative anatomy on the vegetative organs of genus Ziziphora L. (Lamiaceae) from Turkey.

The genus Ziziphora L. (Lamiaceae) is represented by five species (nine taxa) in the Turkish Flora. These taxa are Z. clinopodioides Lam. (subsp. elbursensis, subsp. filicaulis, subsp. kurdica, subsp. rigida), Z. capitata L., Z. persica Bunge, Z. tenuior L., Z. taurica Bieb. subsp. taurica, and Z. taurica Bieb. subsp. cleonioides (Boiss.) Davis which to be an endemic taxon for Turkey. They are strongly aromatic herbs which contain rich pulegone and used as herbal teas and spices and for this reason. In this study, comparative anatomy of the genus Ziziphora growing in Turkey is presented for the first time. In anatomical studies, cross sections of vegetative organs such as the root, stem, and leaf (lamina and petiole) were examined. In addition, to exhibit stomatal distribution and anatomy on adaxial and abaxial leaves were taken surface sections of the lamina and calculated stomatal index. Lamina and petiole anatomy were shown to be of great importance in the taxonomy of the Ziziphora taxa. The presence or absence of sclerenchyma in midrib of lamina and petiole, cortex parenchyma layer, mesophyll structure, and epidermal surface were found to be important characters for identification of Ziziphora taxa.

Leaf shape deters plant processing by an herbivorous weevil.

The shapes of plant leaves are remarkably diverse, but their ecological functions are largely unknown. Reports on the effects of leaf shape on biotic interactions such as herbivory are especially scarce, partly because herbivorous insects rarely rely on leaf shape for host selection. Here, we show that leaf shape acts as a physical deterrent against a leaf-processing herbivore. Plants in the genus Isodon (Lamiaceae) host a specialized leaf-rolling weevil (Apoderus praecellens) whose ovipositing females process an entire leaf into a leaf roll to serve as larval food and shelter. Among the species of Isodon, I. umbrosus var. hakusanensis is exceptional in that it has deeply lobed leaves. Because leaf processing follows a consistent sequence of complex behaviours, the unusual shape of I. umbrosus leaves may disrupt this process. Under both natural and laboratory conditions, female weevils preferred I. trichocarpus, a close relative with non-lobed leaves, over I. umbrosus. Nutritional properties of the leaves do not explain this preference because weevil larvae developed equally well on both hosts. Modifying the non-lobed I. trichocarpus leaves to mimic the shape of I. umbrosus leaves also discouraged leaf processing. Leaf processing often terminated because weevils failed to complete the inspection routine on I. umbrosus leaves. Leaf shape may be an important but overlooked factor that affects the interactions between plants and leaf-processing herbivores.

Taxonomic significance of foliar epidermal morphology in Lamiaceae from Pakistan.

Foliar micromorphological features are useful to elucidate the taxonomy and systematics of the Lamiaceae species. Leaf epidermal morphology using scanning electron microscopy and light microscopy of 22 Lamiaceae species from 15 genera have been investigated with an aim to solve its taxonomic problem in the correct identification. Various foliar micromorphological features were observed to explain their importance in resolving the correct identification of Lamiaceae taxa. Two main types of trichomes were observed; glandular trichomes (GTs) and nonglandular trichomes (NGTs). GTs were further divided into seven subtypes including the capitate, subsessile capitate, sessile capitate, sunken, barrel, peltate, and clavate. Similarly, NGTs were also divided into simple unicellular and multicellular including conical, falcate, cylindrical, dendrite, papillose, and short hook shape. Quantitative measurement includes the length and width of the trichomes, stomatal complex, epidermal cells, stomata, and trichomes index. Based on the foliar micromorphological characters, a taxonomic key was developed to delimit and correctly identify studied taxa. Further molecular, other anatomical and phylogenetic studies are recommended to strengthen the systematics of Lamiaceae.