Floral anatomy ofHypseocharis (Oxalidaceae) with a discussion on its systematic position

The floral anatomy of threeHypseocharis spp. has been studied. The genus resemblesOxalidaceae as well asMonsonia andSarcocaulon of theGeraniaceae. As it is closer toGeraniaceae than toOxalidaceae, it perhaps serves as a connecting link between them.     

Studies on systematic embryology inScilla (Hyacinthaceae)

Scilla persica and 5 species of the so-calledS. hohenackeri group, namely,S. furseorum, S. puschkinioides, S. vvedenskyi, S. hohenackeri, andS. greilhuberi, have been investigated embryologically with special reference to embryo sac and endosperm development.Polygonum-type embryo sac development was stated inS. puschkinioides andS. greilhuberi. 8-nucleate, normally structured embryo sacs, which could not be specified further due to sparse availability of the material, were stated inS. furseorum, S. vvedenskyi, andS. hohenackeri. InS. persica the embryo sac develops according to the bisporicAllium-type. In most species endosperm development was stated to be nuclear, exceptS. hohenackeri, where the type could not be specified. Other traits of possible taxonomic significance are the number of layers in the outer integument, which is mostly 4, or 5–6 inS. furseorum, and the occurrence of polyploid versus haploid and early degenerating antipodal nuclei, the latter occurring only inS. persica andS. furseorum. These embryological characters may be useful for assessing taxonomic relationship of the present species with other allied groups withinScilla, in particular, theS. siberica alliance,S. messeniaca, and theS. bifolia alliance. TheAllium-type embryo sac, which occurs inS. persica, is also characteristic for theS. siberica alliance, and may be a common derived character. Lack of antipodal polyploidization, as characteristic forS. persica andS. furseorum, occurs also in theS. siberica alliance, and is perhaps another common derived trait indicating phylogenetic relationship. Nuclear endosperm development is more frequent in spring-flowering squills than helobial development, which has previously been stated inS. messeniaca, some species of theS. siberica alliance, and inS. litardierei. While helobial endosperm may be primitive forHyacinthaceae in general, it may, by reversal, also occur as a derived character, at least in some species of theS. siberica alliance.     

The systematic position of theHolarrheninae (Apocynaceae)

The genusHolarrhena, described byRobert Brown in 1811, has had a problematic taxonomic history, in part due to a suite of characters that does not conform with accepted concepts within theApocynaceae. In a number of important taxonomic charactersHolarrhena is typical of subfam.Apocynoideae. But due to the relatively unspecialized structure of the anthers most recent authors have placedHolarrheng, together withCarruthersia andSpirolobium, as the subtribeHolarrheninae in subfam.Plumerioideae. For the present investigation the floral structure and pollen morphology ofHolarrhena, Carruthersia andSpirolobium were analyzed. From the chemical literature reports of the occurrence of steroidal alkaloids in thePlumerioideae were evaluated. Our results indicate that the three genera belong to subfam.Apocynoideae in the tribeNerieae, but that the Holarrheninae is an unnatural group, and that the three genera should be accommodated individually within the tribe.     

Embryology and systematic position ofLiparis (Orchidaceae)

The embryology ofLiparis paradoxa andL. rostrata has been studied. The young anther wall consists of an epidermis, endothecium, three middle layers and secretory tapetum with uninucleate cells. In the mature anther, two or three sub-epidermal layers develop fibrous thickenings. The anther wall development corresponds to the massive type. Simultaneous cytokinesis results in decussate, isobilateral, linear, T-shaped and tetrahedral pollen tetrads. The pollinia are compact and at anthesis the pollen grains are 2-celled. Ovules are anatropous, bitegmic and tenuinucellate. Both the integuments are dermal in origin and 2-layered. Development of female gametophyte is of the monosporic, 8-nucleate type. Double fertilization occurs. The primary endosperm nucleus degenerates. The mature embryo is organized from the derivatives of tiers 1, 1, m, and n. Its development conforms to a variation of the Onagrad type. The seed coat is formed entirely by the outer layer of the outer integument. There are three sterile and three fertile valves in the ovary. In the prefertilization stages valves consist of parenchymatous cells. After fertilization, the sterile valves become sclerenchymatous whereas the fertile valves remain parenchymatous. The embryological characters support the disputed systematic position ofLiparis within subtribeLiparidinae ofEpidendreae.     

Hair morphology and systematics ofPhysalis (Solanaceae)

Hair morphology was exammed on developing seedlings and mature plants of ten species from five of seven series inPhysalis. The taxonomic importance of hair development and the distribution of hair types then was evaluated with respect to other comparative data. Two classes of hair types were observed, as found in earlier investigations ofSolanum andRhododendron. The first hair class comprises a sequence from unbranched hairs to dendroid-stelliform hairs. Hairs of this class show considerable variability among taxa in size, presence or absence of glandular tips, and presence and degree of branching, and so were useful in making taxonomic comparisons. The second hair class consists of short hairs, each tipped with a multicellular gland. This second hair class was not useful taxonomically because of its lack of variability in morphology and its often rare occurrence on a plant. The taxa studied exhibit distinctive trichome features which serve to distinguish series and, in some cases together with other data, provided new insight into previously enigmatic species relationships.     

Seed structure and systematic position ofHampea nutricia (Malvaceae)

The mature seeds ofHampea nutricia are glabrous, ovoid, arillate and dark tan in colour. Longitudinal streaks on the seed surface correspond to the underlying integumentary vascular strands. Testa and tegmen are derived from the outer and inner integuments, respectively. The outer epidermis of the tegmen forms a palisade-like macrosclereid layer, the inner epidermis a fringe layer. The endosperm is single-layered and also fills the space between the two cotyledons. The embryo is nearly straight, gland-dotted; it has asymmetrical and folded cotyledons, and gossypol ducts. Systematic position ofHampea is discussed and its placement inMalvaceae is supported.     

Reproductive morphology ofMegaleranthis saniculifolia Ohwi (Ranunculaceae) and its systematic implications

To confirm the taxonomic treatment ofMegaleranthis saniculifolia Ohwi, an endemic genus and species in Korea, we compared its reproductive morphological characteristics with those ofTrollius and other genera within the Ranunculaceae. Although its external morphology might suggest thatMegaleranthis differs fromTrollius, Calathodes, and etc., we found no distinctly different features in this genus. Likewise, previous studies of their pollen structures, chromosome data, and petal morphology have indicated no differences betweenMegaleranthis andTrollius. In fact, related genera share similar characteristics, such as a tetrasporangia anther, glandular tapetum, simultaneous cytokinesis, an anatropous and bitegmic ovule, embryo sac formation of thePolygonum type, exarillate and copious albuminous seed, and several apocarps. Although the unique feature of having both tenuinucellate and crassinucellate ovules simultaneously may initially seem particular toMegaleranthis, it is present in other genera of the same family. Therefore, based on this evidence of reproductive morphology and other information, we suggest thatM. saniculifolia is closely related toTrollius, and should be included within that genus, i.e., asT. chosenensis Ohwi. Nevertheless, we have tentatively placedMegaleranthis within its own monotypic and endemic genus until definitive data become available.     

Embryology ofMalaxis saprophyta,with comments on the systematic position ofMalaxis (Orchidaceae)

InMalaxis saprophyta, anther wall development corresponds to the Monocotyledonous type. The uninucleate tapetum is of secretory type and the endothecium develops U- and V-shaped thickenings on the inner tangential and radial walls. Cytokinesis is simultaneous; tetrahedral, isobilateral and T-shaped tetrads are formed which are compactly aggregated in pollinia. At anthesis the microspore tetrads are 2-celled. The ovule is anatropous, bitegmic and both integuments are dermal in origin. A single hypodermal cell develops directly into a megaspore mother cell. Embryo sac development is predominantly monosporic and less often bisporic. Irrespective of the type of development, the mature embryo sac is 6-nucleate. Although double fertilization occurs, the primary endosperm nucleus degenerates. Embryogeny is of the Onagrad type. The mature embryo lacks differentiation into cotyledon, plumule and radicle. The reticulate seed coat is formed entirely by the outer layer of outer integument. There are three sterile and three fertile valves in the ovary. Although initially parenchymatous, the entire three sterile valves in the ovary and the upper half of the three fertile valves become sclerified after fertilization. The embryological characters support the disputed systematic position ofMalaxis within subtribeMalaxidinae ofEpidendreae.     

Floral organogenesis in Tetracentron sinense (Trochodendraceae) and its systematic significance

In Tetracentron sinense of the basal eudicot family Trochodendraceae, the flower primordium, together with the much retarded floral subtending bract primordium appear to form a common primordium. The four tepals and the four stamens are initiated in four distinct alternating pairs, the first tepal pair is in transverse position. The four carpels arise in a whorl and alternate with the stamens. This developmental pattern supports the interpretation of the flower as dimerous in the perianth and androecium, but tetramerous in the gynoecium. There is a relatively long temporal gap between the initiation of the stamens and the carpels. The carpel primordia are then squeezed into the narrow gaps between the four stamens. In contrast to Trochodendron, the residual floral apex after carpel formation is inconspicuous. In their distinct developmental dimery including four tepals and four stamens, flowers of Tetracentron are reminiscent of other, related basal eudicots, such as Buxaceae and Proteaceae.     

SEM observations on seeds ofStriga spp. andBuchnera americana (Scrophulariaceae)

Seeds of the root parasitesStriga (several spp.) andBuchnera americana were examined by means of SEM. The surface patterns of the seeds in both genera resemble each other closely, especially those ofS. angustifolia andB. americana. SomeStriga spp. can be clearly distinguished by their surface characteristics, while this is quite difficult in others. The taxonomic value of the seed surface features ofStriga andBuchnera is discussed.     

The pollen morphology ofOdontites (Scrophulariaceae) and its taxonomic significance

The pollen morphology of 29 species ofOdontites and related genera was examined by light and scanning electron microscopy. Three major pollen types differing fundamentally in exine sculpturing were found. In the parasitic tribePedicularieae retipilate sculpturing is the most widespread type representing a plesiomorphic character state from which the two other types are derived. Of these, reticulate sculpturing is confined toOdontites, whereas a complex retirugulate pattern was found only in the monotypic Near East genusBornmuellerantha. Within the retipilate and the reticulate major types eight minor types were distinguished based on the differential correlation of exine surface morphology, size, shape and amb form. The pollen data are generally well correlated with macromorphological features and furnish important taxonomic characters at the genus—as well as at the specieslevel.     

Embryology ofEriocaulon setaceum (Eriocaulaceae)

Eriocaulon setaceum can be characterized by: young microsporangium wall with epidermis, endothecium (with fibrous thickenings), and glandular tapetum (uninucleate cells); pollen grains 3-celled, spiraperturate; embryo sac development according to the Polygonum type and with antipodal cyst; endosperm nuclear; embryo small, with incipient differentiation into cotyledonary and epicotylary loci; seed coat mainly from the inner layers of the integuments; pericarp 2-layered and membranous. Embryologically, theEriocaulaceae are nearer to theXyridaceae than to otherFarinosae. Their elevation to the rank of an order,Eriocaulales, therefore appears justified.     

The genusBuxus (Buxaceae): Aspects of its differentiation in space and time

Trends of pollen grain aperture evolution and exine characters as well as characters of leaf venation, petiole and axial vascularization are briefly described and related to geographical distribution and classification ofBuxus. A review of fossil records is given. Three major taxonomic groups can be delimitated within the genus, and aspects of their relationships and chorogenesis are presented. The level of differentiation, the pattern of distribution and the fossil record speak in favour of an ancient origin of the genus.     

The embryology ofEpipogium roseum (Orchidaceae)

Development of pollen and female gametophyte inEpipogium roseum (D. Don)Lindl. has been investigated. The embryo sac conforms to the Apinagia type. The taxonomic position ofEpipogium within the family is discussed.     

Embryology ofKyllinga monocephala (Cyperaceae) and its systematic position

Aspects of the life history ofKyllinga monocephala are described. Anther wall development corresponds to the Monocot type. The endothecium shows spiral thickenings. The tapetum is glandular and has uninucleate cells. Ubisch granules are present. Mature pollen grains (pseudomonads) are 3-celled at maturity. Ovules are bitegmic, crassinucellate and develop a funicular obturator. The embryo development conforms to theJuncus-variation of the Onagrad type. Endosperm, seed coat and pericarp are described.     

The embryology and relationships ofPenaeaceae (Myrtales)

Two species ofPenaeaceae (Penaea mucronata andSaltera sarcocolla), a unique South African family ofMyrtales, were investigated embryologically.Penaeaceae clearly agrees with otherMyrtales in its basic embryological characteristics, and further is characterized by its highly specialized features: ephemeral endothecium, 16-nucleatePenaea-type embryo sac, and unique ovular form. A wider range of affinities of families includingPenaeaceae, Oliniaceae, Rhynchocalycaceae, Alzateaceae, andCrypteroniaceae sensu stricto, as well as a possible common divergence from an ancestral line leading toLythraceae and/orMelastomataceae, are discussed on embryological and other grounds.     

The evolutionary significance of multigermicity in the genusSpinacia (Chenopodiaceae)

The presence of multigerm seedballs in the chenopodiacious genusSpinacia is noted. In the wild, colonising, and weedy dioecious species,S. turkestanica andS. tetrandra, the distribution of a multigerm seedball could effectively overcome the problem posed by isolation of the sexes. The hypothesis is tested assessing the extent of intra-seedball progeny hybridisations and seed production in the two wild species. The success in seed production by intra-seedball progeny crosses suggests that the distribution of such seedball progeny groups permits not only a percentage survival under isolation of these dioecious plants, but also the colonisation of areas outside that of the parent populations.     

The systematic relationships ofAegialitis (Plumbaginaceae) as revealed by pollen morphology

Light and first SEM observations on the pollen ofAegialitis indicate that the two species of the genus are clearly distinguishable from all other genera of the tribeStaticeae to whichAegialitis presently is relegated. Intraspecific exine or aperture dimorphism which appears frequently in this tribe, is not recorded in this genus.A. annulata andA. rotundifolia have distinct monomorphic pollen and show a great resemblance in exine features with the tribePlumbagineae, particularly species ofPlumbago. Considering these and other features, separate subtribal status forAegialitis within thePlumbagineae is proposed.     

凤仙花属棒凤仙亚属(凤仙花科)植物花粉形态的分类学意义

棒凤仙亚属代表着凤仙花属最先分化出的一支,以多年生草本,多于5朵花的总状花序,侧生萼片4枚,3沟花粉,心皮四室且每室具1枚种子,果实棒锤状,种子椭圆形以及三沟花粉其极面观为三角形而区别于其它种类。该亚属主要分布于中国南部,少数种类辐射分布至华中和中南半岛地区。已有报道证实花粉的形态特征对凤仙花属植物的属下分类具有重要意义,但对棒凤仙亚属的种类少有涉及。为了进一步探讨该亚属花粉的形态特征及其分类学价值,该研究应用扫描电镜技术对国产棒凤仙亚属植物的14种以及凤仙花亚属的窄萼凤仙花的花粉进行了观察。结果表明：棒凤仙亚属的花粉以单粒存在,具3条萌发沟,辐射对称,极面观为三角形或三角状圆形,花粉粒外壁具均匀的网状纹饰,网脊平滑或具波状边缘,网眼中具不同密度的颗粒状突起。棒凤仙亚属的花粉形态与水角属的花粉形态相似,表现出了其原始性;其花粉形态特征与花部形态性状等相关性差,对该亚属的组级分类意义较小,但对于该亚属的种间界定具有重要意义;而其花粉的极面观形状、赤道面观形状以及网状纹饰等变异相对稳定,对于界定该亚属具有重要的分类学价值。