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 embryology and relationships ofOliniaceae

Two of the five species ofOliniaceae (Olinia emarginata andO. ventosa), a monotypic and problematic family of theMyrtales, were investigated embryologically.Oliniaceae clearly agree with otherMyrtales in their basic embryological characteristics, and are characterized further by having an ephemeral endothecium, a campylotropous ovule, and a thick, three-five-layered, outer integument. A combination of these three characteristic features is unknown elsewhere inMyrtales, so that embryological features do not support a close relationship with any other member of the order. Shared distinctive anther characteristics (i.e. ephemeral endothecium) suggest thatOliniaceae are derived from the common ancestor ofCrypteroniaceae s. str.,Rhynchocalycaceae, Alzateaceae, andPenaeaceae.     

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.     

The embryology of angiosperms: Its broad application to the systematic and evolutionary study

Embryology allows one to work with a wide array of characters (more than 50 in general) for each taxon of angiosperms. This paper, while providing a brief review of recent studies on Myrtales and associated families by me and my co-workers, discusses evidence for the general utility of embryological characters for the study of plant systematics. In particular, evidence is given that characters of seed coat anatomy may be best applied to the study of specific and sectional (and even familial) relationships, those of seed appendages as well as of integumentary morphology and histogenesis to the study of generic relationships, and other major characters to the study of familial relationships. Embryology thus provides many features that are complex and, when properly applied along with evidence from other sources, offers good indications of relationships at various taxonomic level, from the ordinal to the specific level. Despite its evident systematic value and increasing need, however, information on embryological characters is still lacking for a majority of genera, and even at the family level, data is lacking or insufficiently available for more than 30% of families. Recipient of the Botanical Society Award for Young Scientists, 1987.     

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.     

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.     

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.     

Studies in the embryology of the diandrous orchidCypripedium cordigerum (Cypripedieae,Orchidaceae)

The anther wall layers ofCypripedium cordigerum are six to eight. The glandular tapetum is 2- or 3-layered and its cells are uninucleate. Simultaneous cytokinesis results in decussate, isobilateral and tetrahedral pollen tetrads. Ripe pollen grains are 2-celled. The mature ovules are anatropous, bitegmic and tenuinucellate. Both the integuments are dermal in origin and 2-layered. The inner integument alone forms the micropyle. The female gametophyte is 6-nucleate and bisporic. The reduction of nuclei is due to the strike phenomenon. Double fertilization occurs. The primary endosperm nucleus divides to form two free endosperm nuclei. The mature embryo is undifferentiated. The cells ca, m and n contribute to the embryo. The suspensor is single-celled. 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 these valves consist of parenchymatous cells with starch and raphides. After fertilization, the sterile valves develop sclerotic cells whereas the fertile valves remain parenchymatous. The pericarp structure and embryological features support the retention of tribeCypripedieae within theOrchidaceae.     

西畴重楼生物学特征补述及其系统位置

西畴重楼(Paris cronquistii var.xichouensis)为云南省特有物种,野外调查发现了广西(田林、那坡)的省级新分布,针对该新分布居群,观测并描述西畴重楼植物形态学特征,记录物候学特征,野外观测其地理分布特征,综上对其生物学特性进行补述,并结合前人基于细胞核ITS、叶绿体psbA-trnH和trnL-trnF等序列的分子系统学研究结果探讨其系统关系。结果表明:西畴重楼叶背面无紫色斑块,花瓣较宽而显著区别于凌云重楼(P.cromquistii var.cromquistii),但西畴重楼部分植株沿叶脉有紫色斑纹,表明与凌云重楼存在形态过渡,二者雄蕊数量均以3轮为主,而且变化范围一致;西畴重楼的物候期与同域分布的凌云重楼相近,同南重楼(P.vietnamensis)差异显著;西畴重楼多条序列的分子系统学研究显示西畴重楼和凌云重楼始终聚为一支,证实二者高度的亲缘关系。该研究结果完善了西畴重楼的生物学特性描述,首次报道了西畴重楼与凌云重楼形态特征存在过渡类型,物候学特征较一致,地理分布中心重叠,分子系统学位置相邻,仍支持李恒系统将西畴重楼作为凌云重楼的一变种。     

Contributions to the morphology,anatomy, and karyology ofRhabdodendron,and a reconsideration of the systematic position of theRhabdodendronaceae

Rhabdodendron macrophyllum (Spruce ex Benth.)Huber andR. amazonicum (Spruce exBenth.)Huber differ in several anatomical and morphological characters (secretory cavities, hypoderm, peltate hairs, internodal region and petiole). A position of the monotypicRhabdodendronaceae in theCentrospermae as recently suggested is hardly supported: Peltate hairs, lysigenous secretory cavities and spicular cells in the leaves, multilacunar nodes, chromosome number (R. macrophyllum: n = 10; first count for the genus resp. family), ± simultaneous (or slightly centripetal) development of the androeceum, anacrostyly and two ovules in the unicarpellate gynoeceum, apparent disc, monotelic racemes, and data available from literature (pollen, sieve tube plastids) clearly indicate a close affinity toRutaceae, and even make the family rank ofRhabdodendron questionable.     

The grass megagametophyte and its possible phylogenetic implications

The structure of the grasses megagametophyte is considered to be characteristic enough as to deserve a particular place in the megagametophyte typology. Furthermore, it is compared with those of other Monocotyledonous families to point out embryological affinities.Both are members of the Carrera del Investigador (Conicet, Argentina).     

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.     

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.     

Sieve-element plastids,exine sculpturing and the systematic affinities of theBuxaceae

The sieve-element plastids of members of several genera in theBuxaceae (Buxus, Pachysandra andSarcococca) were found to be of the specific subtype PVI, which contains a central globular protein crystal.Simmondsia (Simmondsiaceae) andDaphniphyllum (Daphniphyllaceae), on the other hand, were found to contain S-type sieve-element plastids. The occurrence of the highly restricted PVI plastids in theBuxaceae mitigates against a close relationship between theBuxaceae andSimmondsia, Daphniphyllum andEuphorbiaceae. Exine sculpturing of theBuxaceae andSimmondsiaceae also shows no close similarities. Both of these EM characters are discussed in connection with other available data and with respect to earlier systematic treatment of these families.     

The genus Valdivianemertes Stiasny-Wijnhoff 1923 (Nemertea,Enopla, Hoplonemertea): nomenclatural status and proper systematic position

The genus Akrostomum was erected by Grube in 1840 for a single species A. stannii which remained a nomen dubium until redescribed by Bürger in 1895 as Amphiporus stanniusi. Bürger (1909) described Drepanophorus valdiviae which shared many characters with A. stannii. Stiasny-Wijnhoff (1923) noted that these two forms belonged neither to Amphiporus nor Drepanophorus and united them in a new genus Valdivianemertes but did not mention the earlier name Akrostomum nor a family affiliation. Several major characters are examined. The nomenclatural status is analyzed, with retention of the junior synonym Valdivianemertes, and the type species is fixed as V. stannii by subsequent designation. Family affiliation is discussed, and the genus is transferred to the Cratenemertidae.     

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.     

On the taxonomic position ofSilene thebana (Caryophyllaceae)

Silene thebana Orph. exBoiss. is transferred as a subspecies toS. fabaria (L.)Sm., resulting in the new combinationS. fabaria (L.)Sm. subsp.thebana (Orph. exBoiss.)Melzh. The chromosome count of 2n = 24 is recorded for the first time for this taxon.Dedicated to Prof. DrK. H. Rechinger on the occasion of his 80th birthday, 16th October 1986.