Leaf anatomy inTigridieae (Iridaceae)

A biometric study of theSarcocapnos crassifolia complex from eastern Andalusia (Spain), Algeria, and Morocco was carried out. Twentytwo populations were used in a principal components analysis based on 14 variables. The results support the recognition of two species,S. crassifolia andS. pulcherrima, spec. nova. The taxon described byBoissier asS. speciosa (S. crassifolia subsp.Speciosa) is maintained inS. crassifolia.     

Leaf anatomy and relationships of Dietes (Iridaceae)

The leaf anatomy of Dietes is described, including all 6 species. Characters support the morphological evidence that Dietes is a distinct genus and related to other Iridoideae. Certain features, notably the epidermal structure and sheath vasculature, distinguish it from other Iridaceous genera, although the sheath vasculature indicates a relationship with some New World Iridoideae. The leaf margin type is similar to that of other Old World Iridoideae. Many leaf anatomical characters in Dietes are associated with xeromorphy. Leaf anatomy supports the division of Dietes into 2 subgenera.     

Floral anatomy of Paepalanthoideae (Eriocaulaceae, Poales) and their Nectariferous structures

BACKGROUND AND AIMS: Eriocaulaceae (Poales) is currently divided in two subfamilies: Eriocauloideae, which comprises two genera and Paepalanthoideae, with nine genera. The floral anatomy of Actinocephalus polyanthus, Leiothrix fluitans, Paepalanthus chlorocephalus, P. flaccidus and Rondonanthus roraimae was studied here. The flowers of these species of Paepalanthoideae are unisexual, and form capitulum-type inflorescences. Staminate and pistillate flowers are randomly distributed in the capitulum and develop centripetally. This work aims to establish a floral nomenclature for the Eriocaulaceae to provide more information about the taxonomy and phylogeny of the family. METHODS: Light microscopy, scanning electron microscopy and chemical tests were used to investigate the floral structures. KEY RESULTS: Staminate and pistillate flowers are trimerous (except in P. flaccidus, which presents dimerous flowers), and the perianth of all species is differentiated into sepals and petals. Staminate flowers present an androecium with scale-like staminodes (not in R. roraimae) and fertile stamens, and nectariferous pistillodes. Pistillate flowers present scale-like staminodes (except for R. roraimae, which presents elongated and vascularized staminodes), and a gynoecium with a hollow style, ramified in stigmatic and nectariferous portions. CONCLUSIONS: The scale-like staminodes present in the species of Paepalanthoideae indicate a probable reduction of the outer whorl of stamens present in species of Eriocauloideae. Among the Paepalanthoideae genera, Rondonanthus, which is probably basal, shows vascularized staminodes in their pistillate flowers. The occurrence of nectariferous pistillodes in staminate flowers and that of nectariferous portions of the style in pistillate flowers of Paepalanthoideae are emphasized as nectariferous structures in Eriocaulaceae.     

Systematic root anatomy of Asparagales and other monocotyledons

Root anatomy of several taxa of Asparagales and some taxa formerly included in Asparagales is described in a systematic context together with a literature review. The presence of a dimorphic outer layer with long and short cells is widespread in monocotyledons, indicating that it originated early in the monocot lineage, but whereas this layer is rhizodermal in most monocotyledons, in Asparagales and Araceae it is usually hypodermal. There may be a correlation between the presence of a velamen or a persistent rhizodermis in many Asparagales and Araceae and the presence of a dimorphic hypodermal layer. Many other root anatomical characters, such as the presence of vascular bundles in the central pith and a multi-layered sclerenchymatous cylinder, are probably xeromorphic and developed convergently.     

Leaf anatomy of the subtribe Hyptidinae (Labiatae)

The leaf anatomy of the subtribe Hyptidinae (Labiatae), which consists of four small genera and the largr genus Hyplis , is dercribed. The leaves may be dorsiventral or isobilateral. Variable characters of the lainina include: frequency and forms of trichomes, cuticular markings, presence of adaxial stoinata, thickness of leaf, thickness of adaxial epidermis, presence of a hypodermis, occurrence of sclcrified tissues (especially sclerified bundle sheath extensions, phloem and xylem fibres), mesophyll structure and venation pattern. Petiole vasculature varies from simple to complex, sometimes with medullary traces present. Most of the variable characters are related to xeromorphy and are tax-onomically useful within the framework of the present classification.     

Leaf anatomy of the subtribe Conceveibinae (Euphorbiaceae)

A comparative study of the leaf anatomy of the subtribe Conceveibinae was carried out. Leaves show a similar structural arrangement in all species, however, there are small variations among the taxa that allow definitions of species or groups. It is not possible to recognize infrageneric divisions or to maintain some genera as different from Conceveiba. The analysis included the study of 11 characters of taxonomic importance of the leaf: the form, the size and the apex of the papillae of the lower side of the blade, the number of layers of the palisade parenchyma, the presence or absence of the midrib pith, the number of vascular bundles of petiole as well as the central cylinder and the medulla, and the presence or absence of the sclerenchyma in the different levels of the petiole. The results are evaluated from a taxonomical point of view. With leaf anatomy characters only, it is possible to separate the genus Conceveiba in the subtribe.     

Author and type of the name Iris cengialti (Iridaceae)

Abstract

A. Kerner is correctly the author of the name Iris cengialti previously ascribed to Ambrosi, and consequently the type of the species is here selected, as lectotype, among Kerner's original material kept in WU.     

Anatomy and morphology of Behnia (Behniaceae) and its relationships within Lilianae: Asparagales

The vegetative and floral anatomy, morphology, embryology and seedlings of Behnia reticulata (Thunb.) Didr. are described, and the relationships of the recently described endemic southern African monocot family Behniaceae Reveal are discussed. Recent molecular studies place the family with the Agavaceae, Hostaceae, Anthericaceae, Herreriaceae and Ane-marrhenaceae. Behnia shows some morphological similarities with this clade, such as the woody shrub habit, a secondary thickening meristem in the rhizomes, small flowers and baccate fruits; but differs in several features, such as reticulate leaf venation, cryptodioecious flowers and seeds lacking phytomelan. Embryologically, the Behniaceae agree with the other members of their clade, although there are no clear synapomorphies by which the group may be defined from other Asparagalean clades.     

Biosystematic studies in European species ofGladiolus (Iridaceae)

Representative specimens of the EuropeanGladiolus species (excl.G. palustris) were used to study variability and relationships. 25 characters were measured for cluster, principal component and Wells hybrid analyses (Figs. 1–3). Three (with PCA) respective five (cluster analysis) main groups are revealed. Bulb characteristics appear to be very useful for indentification. The subspecific status ofG. communis subsp.byzantinus is confirmed. Hybrids of four different parental combinations were detected in our collection. Most species include polyploid series. Partly 3x, 4x, 6x, 8x, 12x and aneuploid cytotypes but no diploids were found. Polyploids as pioneers and hybridization of sympatric species are apparently linked to migrations during the glacial periods.     

Seed coat structure ofCrocus vernus agg. (Iridaceae)

Cytotypes of theCrocus vernus aggregate differ slightly in their seed surface patterns.Crocus albiflorus may be grouped together withCrocus vernus subsp.vernus, both are relatively easily distinguishable by their seed surface patterns from theCrocus scepusiensis—Crocus heuffelianus group.     

Leaf anatomy of the genus Psoralea sensu stricto (Psoraleeae, Papilionoideae, Leguminosae)

Leaf anatomy is described from 17 species of Psoralea sensu stricto which includes four species of the genus Hallia Thunberg. Species of the two genera share many characters including the presence of rod-shaped crystals, similar stipule structure and a possible continuum in secretory cavity anatomy ranging from a small and non-trabeculate to a large and trabci ulate form. Hallia species are distinguished b the presence of large tannin cells in the bundle sheaths and a narrow lcngllv.width ratio of palisade cells. In the light of other floral evidence this is considered insufficient to separate the two genera, a view confirmed by cluster analysis. Thus, Salter's proposal of 1939 for their amalgamation is supported. Leaf anatomy of herbaceous species is compared with that of seedlings of Psoralea sp. to assess the possibility that the herbaceous species may have arisen through neoteny from species that are trees or shrubs. Comparative venation studies between stipules and scale leaves suggest that the scale leaf form arose from pinnate-leaved ancestors by leaf reduction.     

Leaf anatomy of Greyia Hooker & Harvey (Greyiaceae)

The leaves of the three species, viz. Greyia sutherlandii Hooker & Harvey, G, radlkoferi Szyszyl. and G. flanaganii H. Bolus, of the endemic South African genus were studied morphologically and anatomically. Uniseriate branched hairs and uniseriate stalked glands occur on the leaves of G. radlkoferi and G. flanaganii. Mature leaves of G. sutherlandii usually have glands only, but hairs may occur, which are either an ecological adaptation or evidence of a transitional type between G. sutherlandii and G. radlkoferi. The leaves of Greyia are dorsiventral with anomocytic stomata. The latter occur in both leaf epidermides of G. sutherlandii but are rarely present in the adaxial leaf epidermis of G. radlkoferi and G. flanaganii. The uniseriate hypodermis of the lamina is interrupted beneath the stomata only and probably has a conducting function in Greyia , together with the tissues of the epidermis, the bundle sheaths and the bundle sheath extensions.     

Pregamic and postgamic self-incompatibility systems inCrocus (Iridaceae)

Ovule fertilization and seed set were investigated inCrocus thomasii andCrocus vernus subsp.vernus, after different matings. The results gave evidence for a strict ovarian barrier inC. thomasii, which prevents self-fertilization either in self- or mixed- and double-pollination. InC. vernus the ovarian barrier to selfing is not so effective, but a further incompatibility reaction is expressed after self-fertilization resulting in a complete failure of embryogenesis. The implications of the present observations in respect to the mechanisms of pregamic- and postgamic rejection, indicate that a gametophytic system of self-incompatibility controls the ovule fertilization, and a not yet defined system of self-incompatibility controls embryogenesis.     

The systematics of Rigidella (Iridaceae)

Rigidella and the four species contained therein are defined primarily on characters related to, and a direct consequence of, adaptation to hummingbird pollination. The genus is probably derived from either the “multiflora” complex inTigridia subgenusHydrotaenia or is an evolutionary line parallel toTigridia. Illustrations, distribution maps, and a key to the species are included. The rediscovery ofRigidella flammea Lindl. is reported, and a new species,R. inusitata, is described.     

Leaf anatomy and its taxonomic significance in phytelephantoid palms (Arecaceae)

The leaf anatomy of the genera Phytelephas, Palandra and Ammandra (Arecaceae) is described and compared. The anatomical features considered to be of taxonomic importance include: the distribution of fibre bundles and minor veins in mesophyll and hypodermis, the relative size of the cells of the stomatal complex and whether the costal bands of eleongated cells are conspicuous in surface view or not. Species of Palandra and Phytelephas form an anatomically homogenous group. The two species of Ammandra differ in their anatomy, although they have several xeromorphic adaptations in common. This is peculiar as they both grow in humid habitats.     

Self-incompatibility inCrocus vernus subsp.vernus (Iridaceae)

Outcross, self- and mixed pollinations were performed inCrocus vernus subsp.vernus, a species with bicellular pollen, dry stigmas and hollow style. No differences were noted among the above pollinations concerning the germination of pollen and the growth of pollen tubes until the top of ovary. Within 45 min after pollinations 62% of pollen grains germinated. Pollen tubes penetrated the papilla cuticle extending along the papilla wall; on entry into stigmatic lobes they continued growth in the stylar secretion to ovarian locules. Here, however, self-pollen tubes failed to reach or to enter the ovule micropyle; while pollen tubes from either outcross- or mixed pollinations grew until fertilizing ovules. These observations gave evidence of a self-incompatibility system inCrocus, which appeared to be neutralized by mentor effect. The ovary as site of incompatibility response is discussed.     

Crocus sativus and its allies (Iridaceae)

Crocus sativus is an autumn-flowering species, unknown as a wild plant but long-cultivated for its scarlet style branches which yield Saffron, the dye and flavouring agent. There are several naturally-occurring related species from southern Europe and south western Asia which form a natural group within the genus.C. niveus from Greece is similar to these morphologically and is included here but is less closely related. The characters of the group are defined, a key to the taxa is provided and their relationships discussed.     

Radiation in the Cape flora and the phylogeny of peacock irises Moraea (Iridaceae) based on four plastid DNA regions

Phylogenetic analyses of four plastid DNA regions, the rbcL exon, trnL intron, trnL-trnF intergenic spacer, and rps16 intron from each of 73 species in the African genus Moraea (Iridaceae: Irideae) including accessions of all major species clusters in the genus, show Moraea to be paraphyletic when Barnardiella, Galaxia, Hexaglottis, Homeria (all southern African), and Gynandriris (Eurasian as well) were recognized as separate genera. There are several small, isolated species clusters at the basal nodes of the tree that are all restricted to the winter-rainfall zone of southern Africa (the Greater Cape floral kingdom) and a few, highly derived, large species groups that have radiated extensively within the winter-rainfall zone. Mapping of floral traits shows that an Iris-type flower is ancestral in Moraea. Floral changes are associated with shifts in pollination systems, either from passive pollen deposition on long-tongued bees foraging for nectar to active pollen collection by female bees foraging for pollen, fly, or hopliine scarab beetle pollination. Dating the nodes of the phylogenetic tree using non-parametric rate smoothing with a calibration point derived from broad dating of the angiosperms indicates that the divergence between Moraea and its sister genus Ferraria occurred about 25 mya in the early Miocene. The early radiation of Moraea took place against a background of aridification and the spread of open habitats, such as desert, shrubland, and fynbos.     

Intra- and interspecific reproductive barriers inCrocus (Iridaceae)

The reproductive system was studied inCrocus genus (Iridaceae) following intra- and interspecific pollination, by using light and scanning electron microscopy. The results suggest that the stigma-style tract of theCrocus pistil is a mere promoter of pollen tube growth, while intra- and interspecific discrimination of compatible and incompatible pollen occurs in the ovarian tract. Here, the transmitting tissue consists of special epidermal cells, whose granular or floccular secretions provide the selective medium for the growth of pollen tubes. The ovarian self-incompatibility (SI) is widespread within the genus, resulting in a partial or complete suppression of self-fertilization. Moreover, postzygotic SI mechanisms, as well as postzygotic mechanisms of unknown nature, seem to be recurrent and both are responsible for seed abortion. The interspecific ovarian incompatibility concerns only unrelated crosses; crosses between related fertile species succeed both in fertilization and seed-set.