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1.
The vascular anatomy of inflorescence axes and flowers ofClematis patens have been studied. The species shows a unique behaviour of the vascular bundles in the transition node from vegetative stem to pedicel: stelar bundles increase in number from six to eight as they ascend through the transition node so that the number of vascular bundles coincides with that of sepals. In the pedicel stele the resulting eight bundles are disposed opposite to eight sepals. respectively; each sepal receives its vascular supply from the bundle facing it. Morphological and anatomical evidence suggests that the calyx of eight sepals in this species should be interpreted as having consisted originally of four pairs of opposite organs, rather than as having been derived secondarily through chorisis of sepals from a calyx of four sepals as seen in most other species ofClematis.  相似文献   

2.
The basic pattern of the vascular supply to stamens and carpels in the flowers ofClematis is discussed on the basis of serial sections. The bundles of the receptacular stele show fairly regular fusions and divisions in relation to the origin of the vascular supply, giving off a single trace for each stamen or carpel. In many cases the trace arises by the trifurcation of the “fused bundle” and the subsequent departure of the median strand. This is the pattern basic to the structure of the receptacular stele of the genus. Although the basic pattern involves a variety of modifications, each of the diverging traces fundamentally leaves a single independent gap in the stele, contrary to the conclusion of previous authors. Similarities and differences between a group of stamens and carpels and that of sepals and foliage leaves are also discussed based on the results of the present and previous studies on the vascular anatomy of the floral receptacle and the inflorescence axis.  相似文献   

3.
Seedling morphology and vascular course inTribulus terrestris were studied. This species has no erect stem, but four buds appear immediately above the cotyledonary node and grow into prostrate shoots. They were determined to be the main axis of the seedling and the axillary branches of the earliest three foliage leaves, which arise very close to each other. All the leaves, including cotyledons, are vascularized with four bundles among which two are related to a single median gap. When two leaves are attached to one node, lateral traces to the opposed leaves are derived by bifurcation of a single bundle at either side of the stem. In the shoot with a series of alternate leaves, the median pair of traces to every other leaf are found on the same orthostichy. In the branch of which the first node bears no flower but an anisophyllous pair of leaves, the smaller leaf at the node was proven to be the first prophyll because its median traces are superposed by those to the leaf at the next node.  相似文献   

4.
Observations presented here on floral vasculature in Alpinia hainanensis indicate that the labellum incorporates elements of five androecial members rather than two or three, as suggested by previous authors for Zngiberaceae flowers. The pedicel contains an outer ring and a central region of vascular bundles. Three carpellary dorsal bundles (CDs) and three alternatively arranged parietal bundles (PBs) separate from the central region successively. The remaining bundles of the central region run upwards and become the placental bundles to supply ovules. The placental bundles terminate between the top of the locular region and the base of the prolongation. The three PBs divides into about five strands respectively. Of which the outer strand enters into the petal being its midrib and the remaining strands move into the stamen adaxially being the vasculature of the functional stamen and the labellum abaxially being the lateral strands of the labellum. The three CDs divide into about five traces, of which the outer strand becomes the midrib of each sepal and the inner strand runs into the style. The remaining traces re‐unite, re‐divide again in the course up and the two adaxial sets of carpellary dorsals finally enter into the labellum being the marginal traces of it while the abaxial single strand enters into the labellum being its midrib. The two antero‐lateral glands receive small traces without lignified tube elements from the vascular plexus, which fonn in prolongation from both PBs and CDs and a few small strands in the ovary wall. There are no subulate appendages differentiated in the flower of Alpinia hainanensis. Hereby, the median of the sepals, both the marginal portions and the median of labellum, and the style have the same origin in vasculature from the CDs and so do the stamen, the lateral portions of labellum and the median of the petals from PBs. The labellum is supposed to represent three members of the outer androecial whorl by its two marginal portions and the median and two members of the inner whorl by its two lateral parts except the median.  相似文献   

5.
The floral anatomy and morphology of 26 species from the Saxifragoideae and three from the Iteoideae are described and compared. The flowers of the Saxifragoideae are predominantly actinomorphic, partially epigynous and/or perigynous, and pentamerous, with two carpels which bear numerous ovules. There is usually some degree of independence between carpels, and the normally separate styles possess both a canal and transmitting tissue. Generally, staminodia are absent and nectariferous tissue, which is not vascularized, is present. The subfamily is characterized by large multicellular trichomes with globular, often glandular, heads. Placentation may be parietal, axile, or transitional between the two; parietal appears to be a derived condition in the subfamily. The vascular cylinder in the pedicel generally consists of several to many discrete bundles from which diverge ten compound traces at the base of the receptacle, leaving an inner cylinder of vascular strands that coalesce at a higher level into either as many ventral bundles as carpels or twice that number. In the former case, each ventral bundle consists of one-half of the vascular supply to each adjacent carpel and separates into individual ventral strands in the distal half of the ovary. The ventral bundles provide vascular traces to the ovules and, along with the dorsals, extend up the style to the stigma. Each trace diverging in a sepal plane typically supplies one or more carpel-wall bundles, a median sepal bundle, and a stamen bundle. Each petal-plane trace usually provides one or more carpel-wall bundles, a lateral trace to each adjacent sepal, a petal bundle and, in flowers with ten stamens, a stamen bundle. Dorsal carpel bundles are usually recognizable and may originate from traces in either perianth plane. While the position of Ribes remains problematical, its floral structure does not easily exclude it from the Saxifragoideae. Floral structure in the Iteoideae is remarkably similar to that in the Saxifragoideae, the main differences being a lesser degree of independence between carpels, generally narrower placentae with somewhat fewer ovules, and the presence of only unicellular, acutely pointed epidermal hairs as opposed to the relatively complex, multicellular trichomes prevalent in the Saxifragoideae.  相似文献   

6.
In comparing the floral vascular anatomy ofConvallaria majalis andC. keiskei a similar pattern of vasculature was shown. Both have pedicels with six (3 large +3 small) bundles which via radial division and fusion form the tepal, stamen and ovary traces. The outer tepal and outer stamen traces, the dorsals and placentals (i.e. ventral supply) arise from the larger three pedicel bundles, while the inner tepal and inner stamen traces and the septal axials arise from the smaller three. The dorsals, septal axials, and all of the stamen and tepal bundles are fusion products, while the placentals are free, though arising from compound bundles. The overy vasculature lacks both lateral peripherals and terminal cross-connections between the inner bundles and the outer dorsals. The placentation is only axile basally, since the three septa are freed at the mid-ovary level, and the resulting common, upper carpellary cavity is continuous with the hollow style. Normally four ovules are observed in each carpel, with the lower tier associated with the lower solid central axis, and the upper tier associated with the freed septa. The orientation of the ovules is varied (heterotropic). An internal system of stigmatoidal tissue is continuous from the base of each locule to the stigma, and involves micropylar associated obturators. Raphides characterize mature ovaries of both species, though both lack septal glands and septal grooves.  相似文献   

7.
The floral development and anatomy ofChrysosplenium alternifolium were studied with the scanning electron microscope and light microscope to understand the initiation sequence of the floral organs and the morphology of the flower, and to find suitable floral characters to interpret the systematic position of the genus within the Saxifragaceae. The tetramerous flower shows a highly variable initiation sequence. The median sepals and first stamens arise in a paired sequence resembling a dimerous arrangement, but the first sepal and stamen arise on the side opposite to the bract. Transversal sepals and stamens emerge sequentially, as one side often precedes the other; sepals and stamens occasionally arise on common primordia. Initiation of the gynoecium is more constant with two median carpel primordia arising on a sunken floral apex. Several flowers were found to be pentamerous with a 2/5 initiation sequence. Flowers were invariably found to be apetalous without traces of petals in primordial stages; this condition is interpreted as an apomorphy. It is postulated that the development of a broad gynoecial nectary is responsible for the occurrence of an obdiplostemonous androecium. The gynoecium shows a number of anatomical particularities not observed in other Saxifragaceae. The presence and distribution of colleters is discussed.  相似文献   

8.
王文采 《广西植物》2016,36(Z1):85-87
描述了自云南东北部发现的毛茛科铁线莲属一新种,东川铁线莲。此种由于其叶为单叶,萼片直立,雄蕊的花丝和花药均被短柔毛而与曲柄铁线莲近缘,与后者的区别在于其叶呈心状卵形,叶缘具粗牙齿,花序为二歧聚伞花序,以及花药顶端钝,不具短尖头。  相似文献   

9.
王文采 《广西植物》2014,(3):287-289
描述了自云南东北部发现的毛茛科铁线莲属一新种,东川铁线莲。此种由于其叶为单叶,萼片直立,雄蕊的花丝和花药均被短柔毛而与曲柄铁线莲近缘,与后者的区别在于其叶呈心状卵形,叶缘具粗牙齿,花序为二歧聚伞花序,以及花药顶端钝,不具短尖头。  相似文献   

10.
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.  相似文献   

11.
The family Malpighiaceae is considered monophyletic, but the intra-family classification is conflicting. Analyses of floral vasculature allow the identification of reductions, connations and adnations and can even reveal evolutionary steps prior to current floral morphology. The present work analysed the floral vasculature of Janusia mediterranea, Mascagnia cordifolia and Tetrapterys chamaecerasifolia using material processed by traditional methods for light microscopy. A general pattern was observed of three bundle traces supplying each sepal and one trace per petal and stamen; Mascagnia is an exception, as its eglandular sepal has only a median trace but shares lateral traces with adjacent sepals. No dorsal traces are emitted to the carpels; however, three intercarpellary complexes are emitted that divide into six ventral bundles, supplying the ovule. Mascagnia demonstrates connation between the anterior and adjacent sepal glands; reductions of the anterior sepal glands were registered in Tetrapterys and Janusia. This work reveals two distinct processes for gland loss in non-related groups of the family that resulted in similar present appearances. Our evaluation of the number of calyx glands and the processes of glandular loss in species with less than ten glands improves our understanding of the evolution of calyx glands in Malpighiaceae.  相似文献   

12.
姜花(Hedychium coronarium)花部维管束系统解剖学研究   总被引:2,自引:1,他引:1  
姜花(Hedychium coronarium Koen.)花梗横切面整体轮廓呈椭圆形,可分为表皮、基本组织和维管束。维管束在基本组织中呈内、外两部分排列。内部维管束联结成网,形成明显外移的三束心皮背束和内方与心皮背束相间的三束隔膜束。至子房室区,心皮背束继续外移,其中主支进入花萼中脉;小分支内移,与内方一轮维管束联结,后来进入唇瓣中央及2枚侧生附属物。在花萼形成的同时,远轴面的两个隔膜中各形成一个上位腺体;同时两束远轴面隔膜束向外、两侧分别形成3束大分支,外方大分支继续外移成为2枚远轴面花瓣中脉,两侧大分支与原外方内移的子房壁维管束集合成一相连的环状维管束网,后进入唇瓣两侧;近轴面隔膜束形成3枚分支,外方分支成为近轴面花瓣中脉,两侧分支进入可育雄蕊。探讨了侧生附属物和唇瓣的来源,支持子房延长部形成的腺体为隔膜蜜腺的变异结构的观点。  相似文献   

13.
The mature flower ofHarungana madagascariensis (Choisy)Poir. has an androecium of five antipetalous fascicles, consisting of four stamens each. The stamen fascicles alternate with five indented nectary scales. A SEM-study of the floral development, as well as a study of the floral anatomy was carried out to understand whether the nectariferous scales represent staminodia or are receptacular in nature and consequently whether or not the androecium ofHarungana, and theClusiaceae in general, is originally diplostemonous. The five petals originate by the splitting of petal-stamen complexes. Next the upper part of each complex differentiates basipetally in four stamens. The stamens remain fascicled and are lifted on a long stalk at maturity. Five carpel primordia are initiated united in a low ringwall. The five nectary scales appear after carpel inception and develop an external morphology reminiscent of anthers. The floral anatomy reveals an independent origin of sepal median traces and common sepal lateral traces, free petal traces, stamen fascicle traces and alternating vascular tissue which supplies the nectaries. The petal-stamen complexes are the result of a retardation in petal inception, linked with the absorption of petal tissue into the stamen primordia. The development of the stamen fascicles is discussed; it is suggested that they are of a secondary nature and do not appear as a reduction from a multistaminate androecium. The external morphology and vascular anatomy of the scales speaks in favour of a staminodial nature. The comparison with some other species of theClusiaceae gives evidence of a diplostemonous ancestry of the androecium.  相似文献   

14.
The floral vasculature in three allied genera,Plagiorhegma, Jeffersoria andAchyls is investigated, and the results are compared with those ofEpimedium andVancouveria which are related closely toPlagiorhegma andJeffersonia. The vasculature in the receptacle ofPlagiorhegma andJeffersonia is similar, but that ofAchlys is much simpler. Slightly different trace patterns are observed in the sepals ofPlagiorhegma andJeffersonia. InJeffersonia, the 3-trace condition leaving 2 or 3 gaps is most frequently observed, but inPlagiorhegma traces of a double nature leaving a single gap are more frequent. The traces to the innermost sepals, petals and stamens are usually of a double nature leaving a single gap in both genera. Regular division and fusion are not observed in the receptacular stele. The vascular differentiation between sepals and petals is more advanced inPlagiorhegma andJeffersonia than inEpimedium andVancouveria. InAchlys, the traces are all staminal and single throughout their course. Two parts recognized in the pistils ofPlagiorhegma, Jeffersonia andAchlys are traversed by independent vasculature. The comparisons of pistil morphology including vasculature ofPlagiorhegma, Jeffersonia, Achlys, Epimedium andVancouveria lead to the interpretation that the pistils are based on the same morphological plan. The probable evolutionary trend in pistil is then suggested in these five genera.  相似文献   

15.
The floral ontogeny and anatomy ofKoelreuteria paniculata have been investigated to understand the developmental basis for the occurring monosymmetry and the origin of the septal cavities. Petals arise sequentially and one petal is missing between sepals 3 and 5, or rarely between sepals 2 and 5. The eight stamens arise sequentially before petal initiation is completed. The last formed petal and one stamen arise on a common primordium. Two stamen positions are empty (opposite the petal between the sepals 2 and 5, and the petal between sepal 1 and 3); consequently two antesepalous stamens have become displaced. The derivation of octandry from a diplostemonous ancestry, and reduction of the petal are discussed. The triangular gynoecium has a strong impact in obliquely reorganizing the symmetry of the flower, loss of organs, and shifts of stamens. The so-called septal slits occurring within the style are a deepreaching non-nectariferous extension of the stigma. Alternating locular furrows are present which could play a role as pollen transmitting tissue and in the loculicid dehiscence of the capsule.  相似文献   

16.
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.  相似文献   

17.
Six species of Cabomba have been examined although the anatomy of the vegetative axes is based on the study of only C. caroliniana and C. palaeformis. A plant consists of an erect short shoot with decussate leaves which bears axillary flowering shoots and rhizomes. A rhizome bears decussate leaves and may also form axillary flowering shoots or turn upward and become a new short shoot. The phyllotaxies of the flowering shoots are proximately decussate or ternate (C. piauhyensis). The flowering shoots with decussate phyllotaxy change to 1/3 phyllotaxy distally; they bear axillary flowers proximally, and extra-axillary flowers distally. Flowering shoots with ternate phyllotaxy do not change distally but each produces first axillary and then extra-axillary flowers. Decussate vegetative axes and flowering shoots have four vascular bundles; ternate vegetative axes and flowering shoots have six vascular bundles, distantly paired into two or three vascular bundle-pairs, respectively. An elliptical vascular plexus occurs at each node. Each leaf receives one bundle-pair from one trace and each flower three bundle-pairs. A two-level receptacular vascular plexus occurs in flowers; the proximal, larger portion provides traces to perianth and stamens and the distal, smaller portion becomes carpellary traces. Each of the three sepals typically receives five branch traces from a basal principal trace, and each of the three petals receives, typically, three branch traces from a basal principal trace. Sepals and petals generally occur in a single, basally connate whorl. Each stamen receives one trace. Each stamen of three-stamen flowers is opposite a petal; each stamen of six-stamen flowers is aligned with an interval between a petal and adjacent sepal. Each staminal trace, which is just above the principal petal trace, in a three-petal flower, is frequently adnate to the latter trace. Each carpel receives one principal trace from the distal, small extension of the receptacular plexus, and each principal trace becomes three conventional veins of a carpel. Ovules may be borne directly over one of the veins or in any position between veins and are supplied by branches of the nearest vein or nearest two veins. All traces, ovular supply veins and the proximal portions of all veins are amphicribral. The several anatomical and morphological differences in vegetative axes and flowers between Cabomba and Brasenia suggest a greater taxonomic distance between the two genera than commonly supposed. It is suggested that extra-axillary flowers in 1/3 helical and ternate flowering shoots of Cabomba might be advantageous in preventing anthesis of flowers beneath peltate leaves. The aberrant position might be the initial evolutionary step toward what, in other nymphaeaceous genera, has shifted each flower to an adjacent helix. It is proposed that the zigzag stem accompanying the trigonal and sympodial flowering shoots may offer greater stability and floatability in water than the monopodial form. Several suggestions are offered for the variability of ovular positions: 1) the variability is a vestige of former laminar placentation in conduplicate carpels; 2) it is a vestige of a primitive condition antedating the current close association of ovules with ventral carpellary veins; 3) it is an early stage of evolution which might have terminated in laminar placentation and cantharophily, but which was replaced by a trend toward myophily.  相似文献   

18.
Anatomical features of the petiole in several species of Jatropha L. (Euphorbiaceae) are presented as evidence in support of infrageneric relationships. A trilacunar 3-trace nodal pattern is typical for the genus. The vascular supply to the stipules is derived from the branching of the two peripheral leaf traces. The number of vascular bundles range from 11 through 9, 7, 5 and 3, and occur in a ring, as free traces, a medullated cylinder, or as U-shaped free traces. The reduction from nine to three bundles is correlated with the gross morphological features while 11, which occurs only in the section Peltatae (Pax) Dehgan & Webster, presents an increase. Reduction in the number of petiolar traces follows the evolutionary advancement of various taxa. This reduction in traces corresponds with south-north distribution of the species and consequential adaptation to colder and more arid climates in Central America and Africa. Smaller leaves, fewer primary veins and fewer vascular traces have resulted as a response to reduced need for water. Presence of dorsal (super-numerary) bundles which supply the petiolar glands in subgenus Jatropha (= Adenoropium Pax) is considered significant, since African taxa of the section (subsection Pubescentes Pax) have retained these bundles despite the loss of petiolar glands. The latter glands are prominent in the South American and Indian species. Sectional lines in the genus can, therefore, be drawn generally on the basis of numerical constancy and relative uniformity in the arrangement of petiolar traces. The continuity of vascular bundles from the stem into the petiole and variations of bundle arrangements are depicted in three-dimensional drawings.  相似文献   

19.
Hylema sp. 5 females oviposit on the undersides of sepals of developing buds of both Ipomopsis aggregata and Polemonium foliosissimum. Eggs deposited on the latter are significantly more likely to be fully protected by the sepal than are eggs deposited on the former. Unexposed eggs have a significantly greater likelihood of successfully developing to the larval stage than do exposed eggs. The difference in frequency of egg exposure on the two plant species can be attributed to differences in sepal morphology: I. aggregata sepals are significantly narrower than those of P. foliosissimum. The hypothesis that females preferentially oviposit on larger flowers was unconfirmed by a manipulative choice experiment. Plants differing in the size of their flowers were potted together and presented to Hylemya in arrays in the field. Flowers of the larger-flowered pair were no more likely to be oviposited on than flowers of the smaller-flowered pair. However, there were significant negative correlations between the corolla length and the percentage of flowers laid on per day at each of two sites. There was also a significant positive correlation between the corolla width and the percentage of flowers laid on at one site. Thus females appear to be using some measure of flower morphology, or a correlated trait, in making oviposition decisions. The degree to which Hylemya is making suboptimal choices between host plant species is discussed and requires further examination.  相似文献   

20.
The in toto pattern of the floral vasculature in Koeberlinia Zucc, is distinctive. The median vascular trace to each sepal is concrescent with the antesepalous stamen trace forming a trace complex. Each petal trace is concrescent with the nearest antestaminal trace, and this common trace is in turn concrescent basally with the common basal supply to the adjacent sepal margins. The ventral carpellary bundles and the ovular traces of the two carpels are arranged for part of the ventral carpellary system into an essentially continuous hollow stele-like cylinder and many of the ovular vascular supplies originate from this strand. All vascular concrescences are congenital. Comparisons of the morphological and floral vasculature characters of Koeberlinia with those of its various putative allies revealed that there are no substantial reasons for linking Koeberlinia with Canotia, Celastraceae, Rutaceae, Simaroubaceae, or Zygophyllaceae. The in toto floral vascular structure of Koeberlinia is closely similar to that of the Caryophyllaceae and dissimilar to that of the Capparaceae. Several qualitative characters of the secondary xylem of Koeberlinia differ from those of the Capparaceae, yet certain important ones are similar. Many of the morphological characters of Koeberlinia are similar to those of the Capparaceae as well as the Caryophyllaceae, yet certain critically important ones strongly indicate a relation of Koeberlinia to the Capparaceae: occurrence of myrosin cells, capparaceous pollen, capparaceous ovular characters. To include Koeberlinia within either of these families is unwise, but the writers are inclined to retain Koeberlinia in a monogeneric family within the larger Capparales.  相似文献   

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