IDIOSPERMUM AUSTRALIENSE (IDIOSPERMACEAE)—ASPECTS OF VEGETATIVE ANATOMY

Vegetative structural features of Idiospermum, a monotypic ranalean genus rediscovered in 1972, are described and contrasted with comparable features of Calycanthus and Chimonanthus (Calycanthaceae) to note resemblances and differences. The leaf trace pattern and nodal anatomy of Calycanthaceae and Idiospermaceae (one-trace and unilacunar) are very similar. The nodal anatomy of certain highly reduced leaves (scale leaves) of Idiospermum is, however, two-trace and unilacunar. The microscopic wood anatomy of Idiospermum is distinctively different in a number of respects from that of the Calycanthaceae. Although there are similarities, it is suggested that the floral anatomy and vegetative features of Idiospermum set it apart sufficiently from the Calycanthaceae to justify family rank as the Idiospermaceae.     

Pollination Processes in Idiospermum australiense (Calycanthaceae), an arborescent basal angiosperm of Australia’s Tropical Rain Forests

Idiospermum australiense (Diels) S.T. Blake, a rainforest canopy tree restricted to a few small populations in northeast Australia, is the only southern hemisphere representative of the Calycanthaceae. Pollination processes in Idiospermum were investigated. Flowers are protogynous, with some populations of the species being andromonoecious, whilst others are hermaphrodite. Over their 10 – 16 day floral lifespan, movements of floral organs enforced spatial and temporal separation of male and female floral function. Changes in colour and intensity of fragrance may also influence their attractiveness to potential pollinators. Pollen is present in large quantities, and appears to act as a reward for floral visitors. Insect trapping was carried out both within flowers, and immediately adjacent to inflorescences. A wide variety of arthropods was trapped, with thrips being the most abundant. Other arthropods were trapped, including fourteen species of beetle. For arthropods other than thrips, the mean numbers of adults trapped on flowers remained more or less constant throughout the floral lifetime. However, there was a significant interaction between floral age and the number of pre-adult arthropods present – as the flower aged, the mean number of larvae and eggs per flower increased. The flowers appear to act as sheltered mating and brooding sites for small insects.     

VASCULAR ORGANIZATION IN SHOOTS OF CACTACEAE. I. DEVELOPMENT AND MORPHOLOGY OF PRIMARY VASCULATURE IN PERESKIOIDEAE AND OPUNTIOIDEAE

Primary shoot vasculature has been studied for 31 species of Pereskioideae and Opuntioideae from serial transections and stained, decorticated shoot tips. The eustele of all species is interpreted as consisting of sympodia, one for each orthostichy. A sympodium is composed of a vertically continuous axial bundle from which arise leaf- and areole-trace bundles and, in many species, accessory bundles and bridges between axial bundles. Provascular strands for leaf traces and axial bundles are initiated acropetally and continuously within the residual meristem, but differentiation of procambium for areole traces and bridges is delayed until primordia form on axillary buds. The differentiation patterns of primary phloem and xylem are those typically found in other dicotyledons. In all species vascular supply for a leaf is principally derived from only one procambial bundle that arises from axial bundles, whereas traces from two axial bundles supply the axillary bud. Two structural patterns of primary vasculature are found in the species examined. In four species of Pereskia that possess the least specialized wood in the stem, primary vascular systems are open, and leaf traces are mostly multipartite, arising from one axial bundle. In other Pereskioideae and Opuntioideae the vascular systems are closed through a bridge at each node that arises near the base of each leaf, and leaf traces are generally bipartite or single. Vascular systems in Pereskiopsis are relatively simple as compared to the complex vasculature of Opuntia, in which a vascular network is formed at each node by fusion of two sympodia and a leaf trace with areole traces and numerous accessory bundles. Variations in nodal structure correlate well with differences in external shoot morphology. Previous reports that cacti have typical 2-trace, unilacunar nodal structure are probably incorrect. Pereskioideae and Opuntioideae have no additional medullary or cortical systems.     

ULTRASTRUCTURAL DEVELOPMENT OF THE BEETLE FOOD TISSUE OF CALYCANTHUS FLOWERS

The flower of Calycanthus traps a wide variety of beetles which, while imprisoned, effect pollination. During their occupancy the insects eat a protein-rich tissue developed at the tips of the inner tepals, stamens, and staminodia. Cells of this food tissue differentiate a large number of cytoplasmic protein tubules by using a protein vacuole as an assembly site. The cells comprising the food tissue represent a very specialized plant cell type and one which facilitates this particular plant/insect relationship.     

Vascular floral anatomy of the east asianHeloniopsis orientalis (Thunb.) C. Tanaka (Liliaceae-Helonieae)

Observations on the vascular floral anatomy, carpel morphology and floral biology ofHeloniopsis orientalis are presented. The lower flowering pedicel has six large bundles which lack an enclosing sclerenchymatous sheath. At mid-pedicel, branch bundles originate via radial divisions from each of these bundles. Subsequently, there is a vascular ring of 12 bundles below the receptacle. The six smaller bundles which are derived from alternate pedicel bundles eventually establish all of the ventral gynoecium supply. The six larger bundles supply the tepals, stamens and dorsal gynoecial vasculature. The simple dorsals do not branch or fuse in their vertical ascent. The ventral and placental supplies are far more complex. Fusion occurs between paired sets of the six smaller pedicel bundles along the septal radii and results in a submarginal laminal ventral network. An independent ventral plexus is formed in each septum and from each plexus two septal axials, of which the innermost has a reversed xylem-phloem disposition, and four placental bundles are derived. Two placental bundles are associated with each septal axial. Basally the septa are fused centrally, but are freed at mid-gymoecial height. The broadly tri-lobed, tri-carpellate gynoecium is depressed terminally where the erect, hollow style with its capitate stigma is attached. Dorsal grooves are present: the fruit is loculicidally dehiscent. There are no septal glands due to complete lateral fusion of the septal wings. Basally each of the six equal tepals has a saccate nectary. The similarity in vascular anatomy and carpel morphology of the AsianHeloniopsis and eastern North American endemic,Helonias bullata, justifies their position in the same tribe. Research and publication supported in part by the M. Graham Netting Research Fund through a grant from the Cordelia Scaife May Charitable Trust, the U. S.—Japan Cooperative Science Program Grant GF-41367, the Japan Society for the Promotion of Science, and Grant-in-Aid No. 934053 from the Ministry of Education, Japan.     

Population genetic structuring in a rare tropical plant: Idiospermum australiense (Diels) S.T. Blake

Idiospermum australiense (Diels) S.T. Blake is considered to be one of the few remaining species of an ancient assemblage to have survived the attrition of Australian tropical rain forest during historically drier periods. This monotypic species is currently restricted to two very wet lowland rain forest locations in Australia’s wet tropical World Heritage Area that are thought to have provided refuge for humid-adapted taxa during the last glacial maximum. Two dominant (RAPD and ISSR) molecular marker sets were employed to investigate whether the genetic structure of Idiospermum could be attributed to its restriction to these quite disjunct localities. The results reveal that neither its restriction to purported Pleistocene refugia nor the geographic distance between populations could fully explain the distribution of variation in the Idiospermum data set, with evidence to suggest that potentially deeper time events have played a role in population structuring and the distribution of diversity. Although there is sufficient evidence in the data to suggest that gene dispersal is quite limited in the species, further investigation is still needed to yield more informative detail on additional factors, such as breeding and germination strategies and their potential influence over population structuring and diversity levels within each population and refugium.     

Morphological evolution in the graminid clade: comparative floral anatomy of the grass relatives Flagellariaceae and Joinvilleaceae

New comparative data are presented on the reproductive morphology and anatomy of two genera closely related to grasses, Flagellaria and Joinvillea, in which the flowers are superficially similar, especially in stamen morphology. This investigation demonstrates some anatomical differences between the two genera. For example, both genera depart from the ‘typical’ condition of tepal vasculature (three‐traced outer tepals and one‐traced inner tepals): in Flagellaria, each tepal receives a single vascular bundle and, in Joinvillea, each tepal is supplied by three vascular bundles. Joinvillea possesses supernumerary carpel bundles, as also found in the related family Ecdeiocoleaceae, but not in Flagellaria or grasses. In the anther, the tapetum degenerates early in Flagellaria, and is relatively persistent in Joinvillea, in which the pollen grains remain closely associated with the tapetum inside the anther locule, indicating a correlation between peripheral pollen (a feature that is common in grasses) and a persistent tapetum. This study highlights the presence of a pollen‐tube transmitting tissue (PTTT) or solid style in the gynoecium of Flagellaria, as also in many Poaceae, but not in Joinvillea or Ecdeiocoleaceae. We speculate that the presence of a PTTT could represent one of the factors that facilitated the subsequent evolution of the intimately connected gynoecia that characterize grasses. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 170 , 393–404.     

THE ORGANIZATION OF THE VASCULAR SYSTEM IN THE STEMS OF THE NYMPHAEACEAE. I. NYMPHAEA SUBGENERA CASTALIA AND HYDROCALLIS

The vascular system in the stems of Nymphaea odorata and N. mexicana subgenus Castalia, and N. blanda subgenus Hydrocallis consists of continuing axial stem bundles with eight being the usual number. The stem bundles are concentric and xylem maturation is mesarch. Xylem elements consist of tracheids with spirally or weakly reticulated secondary wall thickenings. The phloem is made up of companion cells and short sieve tube members with simple sieve plates that are nearly transverse. At the node each leaf is supplied with two lateral leaf traces and a median leaf trace. A root trace is also present and supplies a series of adventitious roots borne on the leaf base. Flowers and vegetative buds develop directly from the apical meristem and occupy leaf sites in a single genetic spiral. Each flower or vegetative bud is related to a leaf through specific spatial and vascular association. The related leaf is separated from the related flower by three members of the genetic spiral and occupies an adjacent orthostichy. Vascular tissue for the related flower arises from the inner surfaces of the four stem bundles supplying leaf traces to the related leaf and extends through the pith to the flower or vegetative bud via a peduncle fusion bundle. The vascular system organization in the investigated species of Castalia and Hydrocallis is not typically monocotyledonous or dicotyledonous, nor can it be considered transitional between them. The ontogeny of the vascular system is similar to typical dicotyledons and the investigated species of Nymphaea can, therefore, be considered to represent highly specialized and modified dicotyledons.     

霉草科,缅甸被子植物一新记录科

在近期缅甸北部的植物考察中,一种菌类寄生植物矮生喜荫草(Sciaphila nana Blume)被发现和确认。矮生喜荫草代表缅甸被子植物一新记录科,霉草科植物。矮生喜荫草主要特征为花单性同株、雄花内轮花被片顶端具有柄的门把状物、花被片6、3个雄蕊、花药4室。     

FLORAL MORPHOLOGY OF HORSFIELDIA (MYRISTICACEAE)

The pistillate flowers of Horsfieldia are morphologically similar to those of Myristica and Knema, and are composed of a single whorl of thick, fleshy tepals, and an unsealed, monocarpellate pistil bearing a single ovule. The carpel is vascularized by two ventral bundles, a pair of dorsal bundles, and several supernumerary bundles. The ovule vascularization is derived from the supernumerary bundles. Paired dorsal vascular bundles are an uncommon feature of uncertain significance. Carpels of Myristica and Knema lack any clearly defined dorsal vasculature, and the ovule vascular supply is derived from both the ventral and supernumerary bundles. The organization of the staminate flowers of Horsfieldia agrees with the myristicaceous pattern observed in Myristica and Knema. Each androecium consists of a single whorl of anthers fused or partially fused to a massive connective column. Each anther consists of a pair of bisporangiate lobes and a single vascular bundle. The androecial forms observed are interpreted as forming a series of intermediates between the monadelphous type of androecia of two South American genera, Compsoneura and Dialyanthera, and one African genus, Brochneura, and the solid, columnar androecia which are predominate in the family. Accumulating evidence supports a proposed South American or west Gondwanaland origin of the Myristicaceae.     

COMPARATIVE STUDY OF THE FLORAL VASCULATURE IN SAURURACEAE

The floral vascular systems are compared among all six taxa of Saururaceae, including the two species of Gymnotheca which have not been studied previously. All are zygomorphic (dorsiventrally symmetrical), not radial as sometimes reported, in conformity with dorsiventral symmetry during organogenesis. Apocarpy in the two species of Saururus (with four carpels and six free stamens) is accompanied by a vascular system of four sympodia, each of which supplies a dorsal carpellary bundle, two ventral carpellary bundles, and one or two stamen traces. The level at which the ventral bundles diverge is the major difference in vasculature between the two species. The other four taxa are all syncarpous, and share some degree of stamen adnation and/or connation. The vascular systems also show varying degrees of fusion. The two species of Gymnotheca (with four carpels and six stamens) are very similar to each other; in both, the ventral traces of adjacent carpels fuse to form a placental bundle, which supplies the ovules and then splits into a pair of ventral strands. The flowers of Houttuynia cordata (with only three carpels and three adnate stamens) are sessile. Each flower is vascularized by three sympodia; the median adaxial sympodium is longer than the other two sympodia before it diverges to supply the adaxial organs. Three placental bundles also are formed in Houttuynia, but the three bundles differ in their origin. The median abaxial placental bundle diverges at the same level as the three sympodial bundles of the flower, while the other two lateral placental bundles diverge at a higher level from the median adaxial sympodium. Anemopsis californica, with an inferior ovary of three carpels, sunken in the inflorescence axis, and six stamens adnate to the carpels, has a vascular system very similar to that of Houttuynia cordata. The modular theory of floral evolution is criticized, on the bases of the known behavior of apical meristems and properties of vascular systems. The hypothesis is supported that saururaceous plants may represent a line of angiosperms which diverged very early.     

Flower heliotropism of <Emphasis Type="Italic">Anemone</Emphasis> <Emphasis Type="Italic">rivularis</Emphasis> (Ranunculaceae) in the Himalayas: effects on floral temperature and reproductive fitness

The flower heliotropism of Anemone rivularis (Ranunculaceae) was investigated on the Yulong Snow Mountain, near Lijiang in the northwest of the Yunnan province of China. We discovered that tepals in this species drive the peduncles to track the sun, and that this flower heliotropism was likely an adaptation for parental environmental effects on reproductive fitness. In brief, A. rivularis flowers retained sun-tracking behavior following removal of pistils and stamens, but lost heliotropic movement, if tepals were removed. Light is the major factor to affect floral heliotropism, the tepal-received light signal was in the blue frequency. Meanwhile, the peduncles were found to bend significantly on the top portion of both control flowers and those lacking pistils and stamens, but instead of keeping a vertical peduncle orientation in flowers with tepals removed. Furthermore, the floral temperature was steadier, and seed sizes and numbers were greater for control flowers than for flowers with tepals removed. Therefore, we conclude that the tepals trigger the flower heliotropism in A. rivularis and play an important role on not only increasing but also keeping optimal thermal condition of flower interior. We further conclude that flower heliotropism enhances the pollen viability and seed production, resulting in higher reproductive success for this alpine species.     

Begonia baik and B. padawanensis spp. nov. (Begoniaceae) from sandstone areas in Sarawak,Malaysia

Two new species of Begonia (Begoniaceae), B. baik and B. padawanensis, from Sarawak are described and illustrated. Begonia baik, a member of sect. Petermannia, resembles B. conipila, but is distinguishable by having glabrous ovary (vs sparsely hispid) and margins of bracts dentate and glandular hairy (vs entire). Begonia padawanensis (sect. Reichenheimia) is similar to B. andersonii, differing in the leaves being obtriangular‐spatulate (vs orbicular) and having 5 pistillate flower tepals (vs 4). Both new species were discovered in a sandstone area in Padawan, Sarawak.     

THE ORGANIZATION OF THE VASCULAR SYSTEM IN THE STEMS OF THE NYMPHAEACEAE. II. NYMPHAEA SUBGENERA ANECPHYA,LOTOS, AND BRACHYCERAS

The anatomy and organization of the stem vascular system was analyzed in representative taxa of Nymphaea (subgenera Anecphya, Lotos, and Brachyceras). The stem vascular system consists of a series of concentric axial stem bundles from which traces to lateral organs depart. At the node each leaf is supplied with a median and two lateral leaf traces. At the same level a root trace supplies vascular tissue to adventitious roots borne on the leaf base. Flowers and vegetative buds occupy leaf sites in the genetic spiral and in the parastichies seen on the stem exterior. Certain leaves have flowers related to them spatially and by vascular association. Flowers (and similarly vegetative buds) are vascularized by a peduncle trace that arises from a peduncle fusion bundle located in the pith. The peduncle fusion bundle is formed by the fusion of vascular tissue derived from axial stem bundles that supply traces to certain leaves. The organization of the vascular system in the investigated taxa of Nymphaea is unique to angiosperms but similar to other subgenera of Nymphaea.     

Developmental morphology of the flower of <Emphasis Type="Italic">Dracontium polyphyllum</Emphasis> in the context of the phylogeny of the Araceae

The inflorescence of Dracontium polyphyllum consists of 150 – 300 flowers arranged in recognisable spirals. The flower has 5 – 6 (90% of observed specimens), or 7 broad tepals enclosing 9 – 12 stamens (occasionally 7) inserted in two whorls. The gynoecium is trilocular (90% of observed specimens) or tetralocular. The tetralocular gynoecia are found at random among the trilocular gynoecia. Each locule encloses an ovule inserted in an axile position, in the median portion of the ovary. Each carpel has its own stylar canal. However, in the upper portion of the style, there is only one common stylar canal. Floral organs are initiated in an acropetal direction in the following sequence: tepals, stamens, and carpels. During later stages of development, the tepals progressively cover the other floral organs. The first floral primordia are initiated on the upper portion of the inflorescence. During early stages of development, the floral primordia have a circular shape. The tepals are initiated nearly simultaneously. During later stages of development, the first whorl of stamens develops in alternation with the tepals and is followed by a second whorl of stamens. The trilocular or tetralocular nature of the ovary is clearly visible during early stages of development of the gynoecium. Recent molecular studies show that Anaphyllopsis A. Hay and Dracontium L. are closely related. However, although pentamerous flowers have been observed in Anaphyllopsis, the developmental morphology of the flower of Dracontium is different from that of Anaphyllopsis.     

VASCULAR CONSTRUCTION AND DEVELOPMENT IN THE AERIAL STEM OF PRIONIUM (JUNCACEAE)

The aerial stem of Prionium has been studied by motion-picture analysis which permits the reliable tracing of one among hundreds of vascular strands throughout long series of transverse sections. By plotting the path of many bundles in the mature stem, a quantitative, 3-dimensional analysis of their distribution has been made, and by repeating this in the apical region an understanding of vascular development has been achieved. In the mature stem axial continuity is maintained by a vertical bundle which branches from each leaf trace just before this enters the leaf base. Lateral continuity results from bridges which link leaf traces with nearby vertical bundles. Development of the provascular system involves a meristematic cap into which the blind ends of vertical bundles can be followed. Leaf traces are produced continuously in association with developing leaf primordia for a period of over 30 plastochrones; they connect with the vertical bundles in the meristematic cap and so establish the essential vascular configuration which is later reorientated through about 90° by overall growth of the crown. The last bundles to differentiate from the leaf do so outside the meristematic cap and thus fail to make contact with the axial system; they appear in the mature axis as blind-ending cortical bundles. Prionium is only distantly related to palms and its vascular histology is quite different. Nevertheless, the course of vascular bundles and the origin of this pattern in the stem resembles that of a palm. It is suggested that we are examining the fundamental pattern of vascular development in large monocotyledons.     

酢浆草叶片及花朵感夜运动的结构机制

为了解酢浆草(Oxalis corniculata)叶片和花朵的感夜性,采用半薄切片方法对其叶枕和花托进行形态解剖学观察。结果表明,黑暗处理酢浆草后叶片完全闭合,3枚叶片以叶轴为轴线向下紧贴闭合。黑暗处理8 h花瓣完全闭合并螺旋成束状,花萼紧贴螺旋的花瓣但不发生螺旋。叶片张开时屈肌侧皮层薄壁细胞收缩,伸肌侧皮层薄壁细胞膨大。叶片闭合时屈肌侧皮层细胞膨胀,伸肌侧表皮细胞和3～5层外皮层薄壁细胞收缩。花朵闭合时,花托基部的5个维管束收缩合并成2束明显分离的维管束群,且存在细胞壁加厚的现象;花托角隅处细胞膨胀。叶枕中的屈肌和伸肌细胞的收缩或膨胀控制酢浆草叶片的感夜运动,酢浆草花朵的感夜运动主要与花托基部的维管束群和花托角隅处细胞的膨大和收缩有关。     

Comparative floral ontogenies among Persoonioideae including Bellendena (Proteaceae)

Floral ontogeny is described and compared in five species and four genera of the hypothetically basal proteaceous subfamily Persoonioideae sensu Johnson and Briggs. The hypotheses surrounding the origin of the peculiar proteaceous flower and homologous structures within the flowers are examined using ontogenetic morphological techniques. Ontogenetic evidence reveals that the proteaceous flower is simple, composed of four tepals, each tepal initiated successively with the lateral tepals being initiated first and second followed by the successive initiation of the sagittal tepals. Each of four stamens is initiated opposite a tepal in a similar sequence to tepal initiation. A single carpel develops terminally from the remaining floral meristem. In taxa of Persoonieae, nectaries are initiated from a broadened receptacle in alternistamenous sites after zonal growth beneath and between the tepals and stamens has begun. The nectaries are interpreted as secondary organs, not reduced homologues of a “lost” petal or stamen series. Developmental variation is present among the examined taxa in several forms including the development of a Vorlaüferspitze (spine) on the upper portion of the tepals, adnation between the anthers and tepals, and formation of the carpel. In Placospermum the early formation of the carpel cleft extends to the floral receptacle and in the other taxa, the carpel cleft is distinctly above the receptacle. Different developmental pathways result in similar mature morphologies of the carpel in Persoonia falcata and Placospermum coriaceum. Bellendena montana is unique relative to the other taxa in having free stamens, a punctate stigma, reduced (not lost) floral bracts, and the floral and bract primordia are initiated from a common meristem. This study provides a foundation for future studies of the developmental basis of floral diversity within Proteaceae.     

CONTRIBUTIONS TO THE MORPHOLOGY OF LEPTOCHILUS AND PARALEPTOCHILUS

Nayar , B. K. (Natl. Bat. Gard., Lucknow, India.) Contributions to the morphology of Leptochilus and Paraleptochilus. Amer. Jour. Bot. 50(4): 301–308. lllus. 1963.—Morphology of L. axillaris and P. decurrens is described; L. axillaris is epiphytic, possessing a wide creeping, soft, parenchymatous rhizome, covered sparsely by peltate paleae, while P. decurrens is rupicaulous, with a short, brittle rhizome having slender sclerenchyma strands and densely covered by basally attached paleae. The vascular cylinder of the rhizome is dictyostelic and composed of a large number of closely placed, thick, vascular bundles with characteristic, thickened, endodermal cells in L. axillaris; it is dictyostelic and composed of a few, slender, distantly placed vascular strands in P. decurrens. Leaf traces are multiple strands which in P. decurrens originate in alternate succession from either side of the dorsal median vascular bundle of the rhizome, but in L. axillaris, from the lateral vascular bundles of the rhizome. The branch traces are paired strands which are lateral in the former and medianly placed in the latter. Scattered sclerenchyma strands occur in the stipe of P. decurrens. Paraphyses are absent in P. decurrens, but filamentous paraphyses occur in L. axillaris. The spores are bilateral and smooth-walled in both, and the prothalli are of the branched, ribbonlike type developing as in Colysis. Prothalli are naked in L. axillaris, but bear sparse mammillate marginal hairs in P. decurrens.     

A B Functional Gene Cloned from Lily Encodes an Ortholog of <Emphasis Type="BoldItalic">Arabidopsis PISTILLATA</Emphasis> (<Emphasis Type="BoldItalic">PI</Emphasis>)

The classical ABC model proposed for flower development in Arabidopsis and Antirrhinum appropriately sheds light on the biological process of flower development and differentiation and serves in manipulating the floral structure of other important ornamental plants. In this study, LLGLO1, a B functional gene from Lilium longiflorum was isolated and characterized. RT-PCR analysis elucidated that temporal and spatial expression pattern of LLGLO1. This putative gene was strongly expressed in 1, 2, and 3 whorl organs, i.e., outer whorl tepals, inner whorl tepals, and stamens. Genetic effect of LLGLO1 was assayed by ectopic expression in model plant Arabidopsis. Transformed plants showed homeotic transformation of sepals into petaloid sepals in the first whorl, which is similar to the transgenic plants of 35S::PI. So LLGLO1 was one member of GLO/PI sub-family gene to function in flower development.