Comparative morphology of the carpel in the Liliaceae: Tofieldieae

The Tofieldieae consist of Narlhecium, Nietneria, Pleea , and Tofieldia. Although the three carpels of the pistil are generally coherent, their bases are separate for a short distance in some species of Tofieldia and in Pleea , where a septal nectary seems to be differentiated. These two genera are also alike in the extension of the chalaza as a filiform hook. The sutures are open at flowering only in some species of Tofieldia. Nietneria is distinguished by its inferior ovary and the alternate structure of the pistil. No raphide idioblasts were found in the carpels of any species.     

Comparative morphology of the carpel in the Liliaceae: Uvularieae

Three genera of the Uvularieae (Kreysigia, Schelhammera, Uvularia) have tricarpellate, syncarpous pistils. Ventral bundles (presumably the united simple septal and placental bundles of a carpellary wing) may be present in Kreysigia and Schelhammera. In Kreysigia the two presumptive ventral bundles from adjoining carpels are fused basipetally in each septum. The septal bundles of the other two genera are either simple (Schelhammera) or in part compound (united) below and simple (separate) above (Uvularia) , hence fused acropetally. In Uvularia , the dorsal bundle of the carpel and the median bundle of the tepal are uniquely tripartite and probably homologous. No raphides were found in the carpels of these genera.     

Comparative morphology of the carpel in the Liliaceae: Wurmbaeae

The two genera of Buxbaum's tribe Wurmbaeae, Anguillaria and Wurmbea , have multiovulate carpels. There are deep septal indentations between the carpels of Anguillaria , but the wings of adjoining carpels are fused to solid septa in most species of Wurmbea. In Anguillaria the carpels have open sutures or prominent commissural markings; in Wurmbea the carpels generally lack these characteristics, and some species have a vascularized, columella-like axis in the centre of the pistil. In both genera there are a dorsal bundle, lateral bundles, and two placental bundles in each carpel. At the inner edge of the septum there are one or two septal bundles in Anguillaria and one or none in Wurmbea. The ovules are monotegmic, the integument and funiculus being partly fused in Anguillaria and mostly fused in Wurmbea. An obturator is present in Anguillaria but absent from most species of Wurmbea.     

Comparative morphology of the carpel in the Liliaceae: Iphigenieae

The pistil in the flowers of the Iphigenieae (Camptorrhiza, Iphigenia, Omithoglossum) is usually tricarpellate. The carpels are coherent generally, with closed sutures and seemingly bitegmic ovules. Camptorrhiza differs from the others in having a single compound style. The pistils of most species of these genera have a common vascular structure: three dorsal bundles which run into the style(s), a number of lateral bundles, six placental bundles, and up to three compound septal bundles. The latter nine bundles usually differentiate from a central vascular plexus above the base of the locules. There may be fewer than three septal bundles in some specieS. When present, the septal bundles usually die out in the ovuliferous region, but in some cases they persist to the apex of the locules.     

Comparative morphology of the carpel in the Liliaceae: Glorioseae

The pistils of the Glorioseae (Gloriosa, Littonia, Sandersonia) are generally tricarpellate and alike. Virtually all have closed sutures at flowering; they have many ovules, some of which are barely bitegmic, with inner integuments often nearly fused with nucellar remnants; and there is usually but one compound septal bundle in the inner edge of a septum. In two species of Littonia , the compound septal bundle divided to form two simple septal bundles; but in many other plants it remained undivided, and in some it died out, still undivided, below the locular apex. Most of the placental and septal bundles are vascularized in large part by three alternate (compound septal) bundles at the base of the locules and sometimes by branches from the lateral bundles. Three large (compound) placental bundles are formed just below the lowermost ovular insertion, and each then divides in two to furnish ovular branches along their ascent. Occasional auxiliary placental bundles lie between the septal bundle and the placental bundles in the septum (Gloriosa, Sandersonia).     

Comparative morphology of the carpel in the Liliaceae: Neodregeae

The structure of the carpel has been studied in flowers of the Neodregeae ( Dipidax and Neodregea ). Except in D. triquetra , which is syncarpous, the carpels are united below and free above. A dorsal bundle, two or more lateral bundles, and two placental bundles supply each multiovulate carpel. The six placental bundles of the tricarpellate pistil are united by twos in the lower part of the pistil, forming three opposite compound placental bundles in most species of Dipidax and three alternate bundles in D. triquetra and Neodregea : In the latter, an additional septal bundle continues upward as a branch from the compound placental bundle. Sutural openings are usually short and restricted to the top of the locule. All the Neodregeae have monotegmic ovules.     

Comparative morphology of the carpel in the Liliaceae: Helonieae

Most Helonieae have only slight septal indentations between the three carpels: in Xerophyllum deep septal clefts extend centripetally and completely enclosed, narrow septal pockets occur in Metanarthecium . Other unique generic features are found: tepallary-staminal nectarial glands in Heloniopsis , zygomorphy in Chionographis , and dioecism in Chamaelirium . The carpels are biovulate in Chionographis; there are two to several ovules per carpel in Xerophyllum; 8–12 ovules occur in the carpel of Chamaelirium; and numerous bitegmic ovules are borne in many longitudinal rows on enlarged placentae in Helonias, Heloniopsis, Metanarthecium , and Ypsilandra . Except for Metanarthecium , this last-named group of genera displays a near ring composed of 'accessory' placental bundles and a compound septal bundle (with normally oriented xylem and phloem) in cross-section at the inner edge of each septum. Ventral bundles occur in the other four genera.     

Comparative morphology of the carpel in the Liliaceae: Veratreae

The genera of the Veratreae, a tribe of the Melanthioideae, have many features in common: there are usually many ovules, except for Amianthium (with 2 4), arranged in 2 -4 longitudinal placental rows per carpel; all are bitegmic, basipetal, and campylotropous. Of 37 species examined, only 2 have open sutures at the lowermost level of ovular insertion, but 13 species have holes in the centre of the pistil. These holes may represent possible stages in the evolutionary closure of previously open sutures. Most flowers were epigynous, only 11 being hypogynous-perigynous. The tribe as a whole is marked by the presence of 3 composite (heterologous) vascular bundles, composed of joined staminal and tepallary bundles alone and 3 composite bundles, as above, fused to a dorsal bundle. The bundles were united below the locular base in all genera except Schoenocaulon and Toxicoscordion. Two major kinds of central cylinder arrangement occurred at the level of the lowermost ovular insertion: either 6 inverted ventral bundles or 6 simple septal bundles, with normally arranged (or sometimes inverted) xylem and phloem centrifugally located and 6 simple placental bundles, with inverted xylem and phloem, at the centripetal end of the septum. Generally each septal bundle united with its nearest adjoining placental bundle about the mid-locular level.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Comparative morphology of the carpel in the Liliaceae: Colchiceae (Colchicum)

The pistil of Colchicum is syncarpous, the carpels having open sutures or well-marked commissures and many bitegmic ovules of variable orientation. Although the vascularization of the carpel is also variable, there are usually three dorsal bundles and three alternate, septal bundles at the base of the pistil, with occasionally some placental bundles at that level. More often the placental bundles, differentiating basipetally, appear to establish connections with the septal bundles higher up, at the lowermost ovular insertion level. The septal bundles divide in two more frequently in pistils in which the carpellary suture is open than in those in which it is closed.     

Comparative morphology of the carpel in the Liliaceae: Colchiceae (Androcymbium)

The pistil of Androcymbium closely resembles that of Colchicum : it is tricarpellate usually, syncarpous and multiovulate, and the carpels of most species have open sutures and bitegmic ovules. The only species with closed carpellary sutures, A. dregei has monotegmic ovules. There are always three dorsal bundles and three compound septal bundles, which latter may bifurcate into simple septal bundles. Six placental bundles (two per carpel) are differentiated, either separately from the compound septal bundles or as lateral branches of them. A statistical evaluation of 47 species (6 genera) of the hemisyncarpous Wurmbaeoideae shows a significant tendency for bitegmic ovules and two simple septal bundles per septum to be associated with open sutures and for monotegmic ovules and no septal bundles to be associated with closed sutures.     

Comparative morphology in the carpel of the Liliaceae: tepallary and staminal vascularization in the Wurmbaeoideae

Tepallary and staminal vascularization in a random sample of the Wurmbaeoideae was eomprised of three vascular bundles per tepal and one per stamen, as in the Rosaceae. The structural similarity of the vascularization of the carpel of the Wurmbaeoideae with that of the Rosaceae is mentioned with the tentative implication of a common ancestry.     

Comparative morphology of the leaf epidermis in Fritillaria (Liliaceae) from China

The leaf epidermis of 16 species and one putative species of Fritillaria was examined using light microscopy (LM) and scanning electron microscopy (SEM). The results showed that the stomatal and other epidermal features were constant within species. Epidermal cells of Fritillaria under LM were usually polygonal and anticlinal cell walls were straight or curved. In a few species they were irregular, with sinuous anticlinal cell walls. The cuticular membrane of Fritillaria was usually striated, and the wax ornamentations were flaked, granular or concomitant. Based on leaf epidermal characteristics, the subdivision of Fritillaria is discussed, and the statistical t‐test method was used to ascertain the significance level of the differences in the stomata of each species. All orientations of the stomatal poles in Fritillaria were the same, and this phenomenon was named ‘stomatal orientation’. The stomatal characteristics support the origin of section Fritillaria in China from two floristic elements. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 160 , 93–109.     

Contributions to the pollen morphology and taxonomy of the Liliaceae

Pollen of 34 species from 7 genera of the Liliaceae were examined by LM and SEM with respect to the taxonomy of the family. Detailed pollen­morphological characteristics are given for all genera in the family on the basis of the results presented here together with data from the literature. The genera Tulipa and Lilium are heterogeneous in both aperture type and exine ornamentation. Pollen of Tulipa is monosulcate, 3-aperturate or inaperturate, with a microreticulate-striate, reticulate-implecto-striate, scabrate, perforate-rugulate, perforate-striate exine surface. Pollen of Lilium is monosulcate and 3-porate with a macroreticulate exine. The other genera are homogeneous in possessing of single longitudinal aperture (type monosulcate). The pattern of exine ornamentation and the structure of the aperture and its membrane are peculiar features for species and genera. Pollen of Erythronium and Tulipa are occasionally operculate, while in other representatives of the Liliaceae an operculum is lacking. Pollen morphological data support the division of the family into 3 tribes, namely Lloydieae, Lilieae, and Tulipeae.     

Pollen morphology and its evolutionary significance in Hemerocallis (Liliaceae)

Pollen morphology of 10 species of Hemerocallis was investigated with LM and SEM. In addition to pollen with reticulate sexine, a new verrucate sexine pattern is found in three Chinese endemic species, H. plicata, H. forrestii and H. nana . Between the two typical sexine patterns, there are transitional variants. Also, a new pollen shape, boat-shaped-elliptic, is observed exclusively in H. nana , besides-oblong shape in other species. Phylogenetically, the common reticulate sexine pattern would be more primitive than the verrucate one. The typical reticulate sexine pattern would be basic, from which transitional variants would have derived and finally led to the typical verrucate pattern. Similarly, the common boat-shaped-oblong pollen would be more primitive than the -elliptic one, from which the latter would have derived during phylogenetic development.     

Clarification of the carpel number in Papaverales, Capparales, and Berberidaceae

For more than 170 years there has been a controversy about the organization of the siliqua, a fruit typical for the Brassicaceae and, in modified forms, also for members of Capparaceae, Papaveraceae, and Fumariaceae. Because in the Berberidaceae fruit forms resembling a “semi-siliqua” are produced, they are also controversial. A siliqua is typically furnished with two placental regions joined by a septum and dehiscing through detachment of two sterile valves. Modified forms lack a septum and have only one or more than two valves, or are indehiscent. The controversial issue is the number of carpels composing a siliqua, typical or modified. Aside from the fact that the nature and phylogeny of the angiosperm organ “carpel” are still insufficiently known and therefore speculative, carpel numbers of two, four, and six have been proposed for a bivalvate siliqua; moreover, an “acarpellate” state as an axis-derived structure has been postulated. Within the framework of these theories there are additional theories concerning the position, shape, and fertility or sterility of what are believed to be carpels. Each of these concepts is reviewed here, and its morphological basis is checked. Gynoecial features used as evidence of the manifold hypotheses are shape of the stigma, zones of dehiscence, structure of the placental regions, vascular pattern, ontogeny, and teratological transformations. They are discussed for each family and compared in the context of the conclusions derived from them. The result is that Robert Brown’s (1817) classical theory, explaining the siliqua as a product of fusion of two transverse carpels with the valves being opercular structures and the septum formed of placental outgrowths, cannot be invalidated by any of the later theories. Stigmatic lobes should not a priori be equated with carpel tips, and their number is not a definite indication of carpel number. The zones of dehiscence are not carpel borders but secondary separation tissues within the carpel blade. Massive placental regions with complex venation need not be solid carpels. Number and course of vascular bundles may be interpreted in ontogenetic and functional terms, and the concept of vascular conservatism is unsound. Gynoecial growth centers must not uncritically be equated with carpel primordia. Terata, such as tetravalvate siliquae, are not atavisms. Thus, carpel numbers higher than those of placentae in the given gynoecium cannot be ascertained. The gynoecium of Berberidaceae is truly monomerous. The identical organization of the gynoecia in the families concerned demands their explanation by a single theory. Many textbooks, floras, and monographs should be revised from this point of view.

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Резюме  Более 170 лет продолжает ся дискуссия о строен ии стручка. Этот плод типичен для семейства кресто цветных (Brassicaceae), а также (в модифицированной форме) для некоторых п редставителей капер совых (Сарраrасеае), маковых (Papaveraceae) и дымянковых (Fumariaceae). Пос кольку у барбарисовы х (Berberidaceae) встречается тип пл ода, который похож на “полустручок”, гинецеи этого семейс тва также обсуждаютс я в связи со структурой типичног о стручка. Существуют р азличные теории о чис ле плодолистиков в стру чке, который в типичном случае сос тоит из двух плацент, о бразующих рамку и связанных перегородкой, а также из двух стерильных ст ворок, отделяющихся при рас крывании от рамки, несущей семе на. (В терминах одной те ории можно объяснить строение модифицированных ст ручков как без перего родки, с одной или многими створками, так и невск рывающихся плодов.) Пр ирода и эволюция плодолисти ка у покрытосеменных еще недостаточно изучен ы, и поэтому умозрительны. Несмот ря на это, различные теор ии предполагают, что двухстворчатый стру чок состоит из двух, четырех или шест и плодолистиков. Кром е того, существует точка зре ния, что плодолистики полнос тью редуцированы и ги нецей произошел из цветоло жа. В зависимости от спосо ба объяснения положе ния, формы, стерильности или фертильности гипоте тических плодолисти ков, теории имеют различные вари анты. В работе приводится о бзор существующих те орий и их критический анализ. Д ля аргументации постоя нно используют следу ющие признаки гинецея: фор му рыльца, характер раскрывани я стручка, строение пл ацентарных областей, анатомию проводящей системы, з аложение гинецея и тератологические из менения. Все эти признаки сравнивают ся у представителей к аждого семейства, а аргумент ация каждой из теории взве шивается и проверяет ся. В результате исследов ания выяснено, что более со временные теории не п риводят весомых аргументов против классической теории Роберта Броун а (Brown, 1817), согласно которой стручок образован дв умя латерально распо ложенными плодолистиками, рамк а является продуктом с лияния их краев, перег ородка является ложной и обр азована в результате срастан ия двух выростов плац ент, а створки — это лишь кро ющие образования. Сравнит ельный анализ призна ков выявил, что лопасти рыльца не во всех случаях соответ ствуют кончикам плод олистиков, их число не всегда сов падает с числом плодолистик ов. Швы, по которым вскр ываются стручки, являются не границами плодолист иков, а вторичными отд елительными тканями внутри пластинки плодолист иков. Массивные плаце нтарные районы со сложным жилкованием не обяза тельно должны быть плодолистиками закр ытого типа. Число и ход проводящи х пучков более логичн о интерпретировать в т ерминах заложения и функции о рганов, теория об эвол юционном консерватизме прово дящей системы необоснован а. Зоны роста на кольце вом зачатке гинецея не всегда можно считать примор диями плодолистиков. Тераты плодов (например, четырехстворчатые с тручки) не являются ат авизмом. Таким образом, число плодолистиков невоз можно достоверно опр еделить: оно больше, чем число плацент в гинецее. Гин ецей барбарисовых действительно моном ерный. Идентичная структур а гинецея у представи телей обсуждаемых семейст в требует одинакового объясне ния в рамках одной и то й же теории. Необходима переработка многих у чебников, флористиче ских и других обзорных свод ок в предложенном аспект е.

     

Nectary morphology in South West Asian Fritillaria (Liliaceae)

Nectaries of 3 1 taxa belonging to 4 subgenera of the genus Fritillaria are investigated by scanning electron and light microscopy. In most of the material investigated nectary cells were smaller and narrower, and less irregular in shape than those of the neighbouring tissue of the tepals. Species belonging to subgenus Rhinopetalum clearly differ from all other species. Their nectaries are deeply impressed, and the slit-like nectary orifice is bordered by two lobes, at least in the lower part densely hairy. In F. gibbosa, E karelinii and F. ariana, the flowers are ± zygomorphic as the nectary on the upper tepal is more deeply depressed than the others, and the nectary lobes are rather broad and fringed. In E stenanthera and E bucharica, nectaries are equally impressed in all tepals and the nectary orifice is bordered by narrow, unfringed ridges. The unique structure of nectaries in all species of this subgenus supports its separation from Fritillaria into a separate genus (Rhinopetalum Fisch. ex Alexand.). In the other subgenera, the nectaries are less impressed, often ± flattish, and usually linear to lanceolate or ovate, except in subgenus Petzlium where they are ± circular. One complex in subgenus Fritillaria is markedly distinguished from the rest of the subgenus: in the F. crassifolia group, the nectaries consist of a long and linear raised ridge with a median furrow. F. crassifolia ssp. poluninii is raised to specific level, E poluninii (fix) Bakhshi Khaniki & K. Persson, stat. nov. It is concluded that data on nectary morphology support the latest classification of the genus Fritillaria into subgenera and informal groups.     

Alkaloids and phenolics of Wurmbea and Burchardia species

The whole plants of four Wurmbea species and one Burchardia species were analysed. All Wurmbea species contained tropolone alkaloids, mainly colchicine, 2-demethylcolchicine, 3-demethylcolchicine and β-lumicolchicine. From all these species the flavone luteolin and 2-hydroxy-6-methoxybenzoic, vanillic and salicylic acids were isolated. Burchardia multiflora yielded one unidentified non-tropolone alkaloid, luteolin, and benzoic and salicylic acids. The chemotaxonomic significance of the substances isolated within the subfamily Wurmbaeoideae is discussed.     

Pollen morphology of the genus Gagea (Liliaceae) in Iran

Pollen grains of 26 species of the genus Gagea distributed in Iran were examined by light and scanning electron microscopy. Detailed pollen morphological characteristics are given for these species. Among the studied species, the newly described G. iranica together with G. olgae and G. graminifolia possess the smallest pollen grains, and the widely distributed G. lutea the largest ones. Our studies show that the sculpturing of exine provides valuable characters for separating the species, sometimes even for closely related ones, and delimitation of natural groups within the genus. The exine of the genus Gagea is in most cases perforated upon tectum or rarely tectate-columellate. The muri are solid or structured, compound, simpli-, dupli- or pluricolumellate. It seems that the structure of muri is very important in recognizing natural groups within the genus. Tectal perforations vary from <0.2 to 2.0 μm in diameter among the studied species. Regarding sculpturing of the exine in proximal face, four basic types of pollen grains can be distinguished: reticulate, microreticulate, foveolate and perforate. Within the reticulate type there is sufficient variation in exine structure at distal face to describe three subtypes: reticulate, microreticulate and perforate. A diagnostic key is given for all studied taxa based on palynomorphological characters. For a limited number of populations of selected Iranian species of Gagea, further aspects of pollen biology were studied. It seems that populations with ploidy levels other than diploidy, show a low percentage of pollen fertility. Moreover, the rate of pollen fertility is correlated with the manner of the reproduction in certain species.