Nutlet Morphology Research Articles

The nutlet morphology of the Genus Glechoma L. (Lamiaceae) and its related taxa

The nutlet morphology and pericarp structure of 14 taxa (4 taxa of the genus Glechoma and related taxa) were studied by light and scanning electron microscopy, and a detailed description of nutlet morphological features for all examined taxa is provided. The shape of the nutlet is ovate to elliptic. Its size is 1.36-3.83 mm in length and 0.80-2.65 mm in width. The largest one was found in Marmoritis rotundifolia, while the smallest one was in Agastache nepetoides. Three different surface types were recognized in the studied taxa based on differences in cell outline and cell boundary relief (rectangular, pitted, and ridged negative reticulate-cell). Three types of trichome (uni-cellular non-glandular trichome, multi-cellular non-glandular trichome, and peltate glandular trichome) were distributed in the nutlets. The pericarp is formed in three layers (i.e., exocarp, mesocarp, and endocarp including sclenchyma tissue), and the pericarp in the studied species is 39.0-237.5 thick. The morphological and anatomical features (the nutlet shape, surface type, and trichome distribution) in the genus Glechoma and related taxa are described and discussed.

Micromorphology and Character Evolution of Nutlets in Tribe Mentheae (Nepetoideae, Lamiaceae)

Mentheae is an economically important tribe in Lamiaceae with many ornamentals and culinary herbs. Although its monophyly is well supported by molecular data, the subtribal delimitation and the intergeneric relationships are still poorly understood. The nutlet morphology (SEM) of the tribe and the presence/absence of myxocarpy is documented here for 57 out of 65 genera in order to assess the systematic value of nutlet characters and to evaluate the existing molecular phylogenies for this group. Significant variation was found in nutlet shape, morphology of the abscission scar, distribution of trichomes, and surface sculpture. Five different surface types were recognized in Mentheae based on differences in cell outline, anticlinal walls, cell boundary relief, and curvature of the outer periclinal wall. Representative nutlet features proved to be phylogenetically informative in Mentheae mainly at the generic level. Cladistic analyses were performed based on 15 morphological nutlet characters and/or available molecular data (nuclear ribosomal ITS and chloroplast trnL-trnF spacer sequences). The resulting topologies indicate that the addition of nutlet characters to the DNA-data matrix improved the overall resolution and also increased bootstrap support values in comparison with exclusively molecular phylogenetic analyses. The evolution of major nutlet characters within the tribe Mentheae is discussed.

Nonea palmyrensis (Boraginaceae): morphology and phylogenetic affinities of a rare endemic of the Syro–Iraqi desert

Based on collections by the authors from the Syrian desert, the morphology and phylogenetic affinities of the rare species Nonea palmyrensis were investigated. An original description and iconography of the species are given, and a lectotype is designated. Micro‐characters were examined by means of scanning electron microscopy (SEM). Clear palynological affinities with the Irano–Turanian species N. longiflora were found. The two taxa share five‐aperturate pollen grains and a micro‐reticulate ornamentation of the tectum. Phylogenetic relationships were analysed using ITS1 sequences of nuclear DNA obtained from 26 species of Nonea. Bayesian and Parsimony analyses retrieved N. palmyrensis as sister to the Mediterranean N. echioides. Together with the Irano–Turanian species N. melanocarpa, they form a moderately supported clade with unresolved relationships. No clear synapomorphies between the three species could be detected in terms of pollen or nutlet morphology. The possibly adaptive nature of some morphological traits peculiar to N. palmyrensis are discussed.

Nutlet morphology and anatomy of the genus Lycopus (Lamiaceae: Mentheae)

Nutlet morphology and pericarp structure of 16 species in the genus Lycopus were studied by light microscopy (LM) and scanning electron microscopy (SEM), and a detailed description of nutlet morphological features for all examined taxa is provided. The nutlets of all taxa in the genus Lycopus are well adapted to typical hydrochory (or nautochory) with an air-filled pericarp, and myxocarpy was not at all found. It is noteworthy that the nutlet morphology (in particular the shape of corky crests and corky ring and the distribution of glandular trichomes) and pericarp anatomy of Lycopus are unique and are well distinguished from the other genera in the tribe Mentheae. We also found some groups of the species within the genus Lycopus by the present nutlet morphological and anatomical data that appear to be useful as diagnostic characteristics for delineation purposes at the specific/interspecific levels. The earlier infrageneric classification for the genus Lycopus is, however, not well supported by the present results. In addition, the systematic and biological implications of the nutlet characteristics investigated are briefly discussed.

Fruit morphology, anatomy and taxonomy of tribe Nepeteae (Labiatae)

The results of a detailed SEM study of nutlet morphology in 156 species of tribe Nepeteae (Labiatae) are presented. Two main types, smooth and sculptured, are described; within them such subgroups as reticulate, cellular, verrucose and tuberculate are defined. The taxonomic significance of these characters is discussed. Pericarp structure was investigated in 34 species. Mucilaginous tubercles were found on the surface of the nutlets in Nepeta, Drepanocaryum and Lophanthus, and their structure is described. In the 10 genera of this widespread tribe, three informal generic groups are recognized, based on a combination of nutlet morphology, pericarp structure and vegetative and floral features.

POLLEN AND NUTLET MORPHOLOGY IN MOSLA (LABIATAE) AND THEIR SYSTEMATIC VALUE

An SEM study of pollen morphology inMoslaand the representative species of the allied genera,Collinsonia, Elsholtzia, Keiskea, Perilla, andPerillula, reveals that the pollen surface sculpture ofMosla(exceptM. cavaleriei) andPerillahas discontinuous ridges, while that of the other genera has the suprareticulate ornamentation. The nutlet surface ornamentation ofMoslaandPerillais also unique. Both pollen and nutlet morphology suggest thatMoslaandPerillaare the most closely related and highly specialized among these genera. The SEM examination of pollen and nutlet ofMoslaprovides no support to the sectional subdivision in this genus.

A new Anchusa from Israel

A new Anchusa (A. negevensis) (Boraginaceae) from the Negev of Israel is described. It is referred to subgen. Hormuzakia (Guşul.) D. F. Chamb. on account of its helmet shaped nutlets with a hollow base and with a basal dentate ring around the ventral side. Although the only other species in this subgenus (A. aggregata Lehm.) is annual, nutlet morphology is strikingly similar between these two taxa. The new species is a perennial, herbaceous plant with succulent roots and reproduces vegetatively by adventitious shoots from its roots. It is known only from a 0.2 hectare area of weathered, Neogene sandstone outcrop, situated with a sloping aspect and subject to high wind erosion, located 10km SE of Dimona, Israel.

Energiedispersive Röntgenmikroanalyse (EDX) von Boraginaceae subfam. Boraginoideae - Klausenoberflächen: (Sind Silicium- und Calcium-Einlagerungen in die Fruchtwand systematisch verwertbare Merkmale?)

The mericarpids ("nutlets") of the four Boraginaceae subfam. Boraginoideae tribes, the Anchuseae. Cynoglosseae. Eritrichieae , and Lithospermeae are known to possess anatomical differences aside from the morphological ones. They differ in the shape of sclerified outer and inner epidennis (exocarp and endocarp) and the presence or absence of a mesocarpal stone cell layer. With its three-layered mesocarp, the Lithospermeae exhibit the most elaborate pericarp anatomy. The stability of the fruit wall is increased by additional deposition of calcium and/or silicon compounds. The exact location of deposition has not yet been identified. The aim of this investigation was to localize these elements within the pericarp and to test whether the depositions are of any systematic relevance within the Boraginoideae (tribal demarcation). Energy dispersive X-ray microanalysis (EDX) was used to investigate the surfaces and inner fruit walls of Boraginoideae nutlets Silicon is present in large amounts on the nutlet surface. Protuberances and glochids in the Eritrichieae and Cynoglosseae tribes contain a particularly high amount of this element. In contrast, calcium is found mainly in cell walls of both meso- and endocarp. Only within the Lithospermeae the lumina of the sclerenchymatic mesocarp are filled with calcium compounds. Potassium always occurs with calcium. The deposition of Ca, K, and Si takes place shortly before nutlet maturity. The distribution of these elements on the nutlet surface does not allow assignment of a species to a particular tribe. Nutlet morphology, pericarp anatomy, and surface sculpturing are better suited for this purpose.

Cruciptera, A New Juglandaceous Winged Fruit from the Eocene and Oligocene of Western North America

Propeller-like samaras from the Eocene and Oligocene of Oregon and from the Eocene of Washington and Wyoming have characters of internal nutlet morphology, sepal and bract con- figuration diagnostic of the Juglandaceae. These fruits, given the new generic name Cruciptera, consist of a globose unilocular nutlet with incomplete primary and secondary septa, four free epigynous sepals, and four elongate wings that radiate from the equatorial plane of the nutlet in the shape of a cross. The wings have subparallel, dichotomizing venation. The genus is also rec- ognized from the middle Eocene of southern England and western Germany. Although the associated foliage and pollen have not been recognized, available fruit characters support placement of Cru- ciptera in the tribe Juglandeae, near extant Cyclocarya and extinct Polyptera. The appearance of Cruciptera in the fossil record post-dates the earliest appearances of Cyclocarya and Polyptera and predates the first confirmed records of Pterocarya. The new combination, C. simpsonii, is also described. The Juglandaceae, with eight extant genera and about 60 species, are distributed in tem- perate to tropical areas, mostly in the Northern Hemisphere. Although the family is best known for the genera with large edible nuts such as Juglans and Carya, most genera possess winged

VARIATION IN NUTLET MORPHOLOGY OF LIMNANTHES

Morphological features of nutlets of all members of the genus Limnanthes were examined by light and scanning electron microscopy (SEM). Eight distinct nutlet types are recognized on the basis of presence or absence, size, shape, density, and color of tubercles and associated filamentous or globular background structures. Some taxa (e.g., L. macounii, L. bakeri) display only one nutlet type, some (e.g., L. floccosa floccosa) have different types in different populations, and others (e.g., L. alba, L. striata) have two or more types within populations. Four classes of nutlets are designated as subtypes on the basis of their forms varying between the eight types recognized. The relationships among various taxa on the basis of nutlet types are schematically diagrammed and compared with other classification schemes. Results suggest that the proposed details of nutlet morphology should be considered in an identification key. Preliminary evidence indicates that certain highly sculptured (tuberculate) nutlet types with large surface areas occur more often in wetter habitats and that variation in this trait in different Limnanthes species might be adaptively associated with geographical distribution patterns.

Variation in Nutlet Morphology of Limnanthes

Variation in Nutlet Morphology of Limnanthes