Molecular phylogeny and taxonomic implications of Asarum (Aristolochiaceae) based on ITS and matK sequences

The genus Asarum (Aristolochiaceae) encompasses approximately 120 species from five sections. Taxonomic controversies concerning the genus Asarum and/or its intrageneric classification remain unresolved. In particular, sect. Heterotropa accounts for a large percentage of the genus (80 of 120 species) and is well diverged in the Sino–Japanese Forest subkingdom. Reconstruction of Heterotropa phylogeny and estimation of its divergence times would provide significant insight into the process of species diversity in the Sino–Japanese floristic region. This study encompassed 106 operational taxonomic units (OTUs), and phylogenetic analyses were conducted based on internal transcribed spacer (ITS) and matK sequences. Although the matK sequences provided informative results solely for section Geotaenium, phylogenetic trees based on ITS regions yielded a clear result for several sections. Three sections, Asarum, Geotaenium and Asiasarum, were supported as robust monophyletic groups, whereas Heterotropa had low support. Sect. Hexastylis was revealed to be polyphyletic, suggesting taxonomic reconstruction would be needed. Sect. Heterotropa comprises two clades, which correspond to species distribution ranges: mainland China and the island arc from Taiwan to mainland Japan via the Ryukyu Islands. It is notable that the common ancestry of the latter clade in the eastern Asian islands was highly supported, suggesting that the present species diversity of Heterotropa was initially caused by allopatric range fragmentation in East Asia.     

Taxonomic studies ofAsarum sensu lato

The karyotype and the C-banding pattern in two species ofHexastylis andAsarum epigynum were analysed in detail, and the results obtained were compared with those of the other species ofAsarum, Asiasarum andHeterotropa previously reported. The present results were partially different from the previous reports related to the karyotypes of these species. The karyotype observed in two species ofHexastylis (2n=26) was represented by ten pairs of metacentric chromosomes and three pairs of small subtelocentric chromosomes, which is very similar to that ofAsiasarum in eastern Asia. The C-banding patterns ofHexastylis andAsiasarum, however, were clearly different from each other. A striking difference was found in one of the three pairs of small subtelocentric chromosomes. A Formosan speciesAsarum epigynum had the somatic chromosome number 2n=12 and a highly asymmetrical karyotype composed of mainly subtelocentric chromosomes. These karyological features were remarkably different from those of the other groups inAsarum s.l.     

Taxonomic studies ofAsarum sensu lato

Fourteen species ofAsarum s. str.,Asiasarum andHeterotropa were studied cytotaxonomically. Their karyotypes and C-banding patterns were examined in detail. The results obtained were different in some important respects from previous reports related to the chromosomes of these plants, and were partially disharmonious with the assumptions presented for the relationships among these genera by some previous workers. Furthermore, it was confirmed thatAsarum s. str. (2n=26) (excludingAsarum leptophyllum),Asiasarum (2n=26),Heterotropa (2n=24) andAsarum leptophyllum (2n=24) are distinct from one another in the karyotype and the C-banding pattern of a few pairs of the small chromosomes in each set. The significance of these small chromosomes in considering the relationships among the plants concerned is discussed.     

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.     

STUDIES ON THE FLORAL ANATOMY OF THE CUNONIACEAE

Twenty-two genera representing sixty-two species of Cunoniaceae and Davidsonia were examined with respect to floral anatomy. Sepals are vascularized by three traces with the lateral traces of adjacent sepals united. Pancheria is unique for the family with species in which the sepals are vascularized by a single, undivided bundle. Petals, when present, and stamens, are uniformly one-trace structures. A general tendency exists within the family for the principal floral bundles to unite in various ways, with fusions evident between calyx, corolla, and androecial vascular supplies. Carpel number ranges from two to five and the gynoecium is generally surrounded by a prominent disc. Gynoecia of Ceratopetalum and Pullea are “half-inferior.” The number of ovules per carpel locule ranges from one to numerous. Ventral carpel sutures range from open to completely sealed at the level of placentation. Carpels of the apocarpous genus Spiraeanthemum (incl. Acsmithia) are vascularized by a dorsal bundle and either three or four bundles constituting the ovular and wing vasculation in the ventral position, a condition unlike other members of the family. Ovules are supplied by the median ventral bundle. More advanced bicarpellate gynoecia within the family are predominately vascularized by a dorsal and two ventral bundles although a variable number of additional lateral wall traces may be present. A major trend exists toward fusion of the ventral bundles of adjacent carpels in the ovary of both bicarpellate and multicarpellate plants. At the base of the styles the fused ventral strands separate and extend along with the dorsal carpellary bundles into styles of adjacent carpels. In Pullea the ventral bundles terminate within the ovules. The united ventral carpellary bundles in Aphanopetalum, Gillbeea, and Aistopetalum lie in the plane of the septa separating adjacent carpels. Ovules are vascularized by traces originating from the vascular cylinder at the base of the gynoecium or by traces branching from the ventral bundles. Ovular traces in each carpel are united, or remain as discrete bundles, prior to entering the placenta. Tannin and druses are common throughout all floral parts. Although floral anatomy generally supports the position of Cunoniaceae near Saxifragaceae and Davidsoniaceae, the evolutionary relationship of the Cunoniaceae to the Dilleniaceae is uncertain.     

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.     

THE PALM GYNOECIUM

The morphology, anatomy, and histology of the gynoecia at or close to anthesis are described for 20 genera of palms selected to represent different taxonomic alliances and to include major gynoecial types within the family. Palms may have 1–10 carpels, but most have three. Fifteen genera, including 14 coryphoid palms and the monotypic Nypa fruticans, are apocarpous and the remainder, approximately 190, are syncarpous. Fusion of carpels in some gynoecia begins in the base, in others in the styles. Pseudomonomerous pistils occur in several different alliances: the ovarian parts of two carpels are reduced but three usually equal and functional styles and stigmas are present. The carpel is often follicular in shape with the ventral suture open or, more frequently, partially or completely closed. The carpel may be stipitate or sessile and usually has a conduplicate laminar part. Most carpels are spirally and laterally inserted on the receptacle, but the carpel in some unicarpellate genera (e.g., Thrinax) appears terminal. Stipes, ovarian parts, styles, and stigmas vary in structure and development. Septal nectaries which differ in size, in the presence or absence of specialized canals, and in position, characterize all genera of some groups but only some genera of others. Diverse vascular configurations in the bases of gynoecia vary according to the extent of the floral axis, the development of carpellary stipes, and the connation of the carpels and their adnation to the tip of the floral axis. Four types of carpellary vascular systems are present in the genera described: (1) most palm carpels have three major traces consisting of a dorsal bundle and two ventral bundles, and they may also have up to four pairs of lateral bundles or occasionally more; (2) in certain cocosoid palms no ventral bundles can be distinguished, but a dorsal bundle, many parallel lateral bundles, and a row of immature ventral strands vascularize each carpel; (3) carpels of Phytelephas have a dorsal bundle, two pairs of major lateral bundles and about four pairs of shorter lateral bundles, with no identifiable ventral bundles; (4) carpels of Nypa have many dichotomously branched bundles but none that are recognizable as dorsal, ventral, or lateral strands. Additional peripheral bundles or systems may be present in each of the above types. Ovules are supplied by 1–15 bundles. These are derived either from the carpellary stele; from ventral bundles only; from ventral, lateral, and dorsal bundles; or from a combination of these origins. Certain areas of the gynoecia or certain parts of dorsal carpellary walls in some genera are much less mature at anthesis than surrounding tissues. Implications for floral biology and relationships within the palms and of palms to other groups are discussed.     

Floral vascular anatomy ofConvallaria majalis L. andC. keiskei miq. (liliaceae-convallariinae)

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.     

Studies in the floral morphology and anatomy of nymphaeales

Floral morphology ofBrasenia schreberi Gmel. andCabomba caroliniana A. Gray was observed chiefly from an anatomical point of view. The receptacle ofB. schreberi is rather flat and a vascular plexus is observable in the mature flower. The vasculature in this plexus is so complex taht it is not easy to trace its structure in detail. by observation on small buds, it can be seen that the receptacular vasculature consists of a girdling bundle in the basal area and usually nine receptacular strands from which traces to the petals and stamens branch off. The vasculature in the receptacle is reconstructed and diagramatically shown as though split longitudinally and spread out in one plane. Floral vasculature inCabomba caroliniana is simpler, and is probably related to the smaller number of stamens and carpels. It also has a girdling bundle at the bottom of receptacle and this vasculature is suggested to be derived by simplification from aBrasenia-type vasculature. Evidence from floral anatomy suggests that these two genera are closely related. InNymphaea, a vascular plexus in the receptacle is also observed (Moseley, 1961; Ito 1983). The plexus ofBrasenia andNymphaea are not the same in their construction. Nevertheless, their fundamental floral vasculature is comparable and it is preferable to place them in the same family or same order.     

Chalcones and other flavonoids from Asarum sensu lato (Aristolochiaceae)

Seventy-five taxa belonging to the genus Asarum sensu lato were studied for their composition of flavonoids. Three chalcones and an aurone were found as major components. The chalcones were identified as chalcononaringenin 2′,4′-di-O-glucoside, 4,2′,4′-tri-O-glucoside, 4-O-glucoside, and the aurone as aureisidin 4,6-di-O-glucoside. The glycoside, 2′,4′-di-O-glucoside was detected in all taxa examined, and is a chemotaxonomical feature of Asarum sensu lato. 4,2′,4′-Tri-O-glucoside was found from the taxa classified into the genera Asiasarum, Geotaenium and Heterotropa by Maekawa's system. On the other hand, the glycoside was not detected from three Asarum sensu stricto species, A. caudigerum, A. caulescens and A. leptophyllum. In contrast, aurone, aureusidin 4,6-di-O-glucoside occurred in two Asarum s.s., A. caulescens and A. leptophyllum. Thus, the Asarum s.s. and other Maekawa's genera, Asiasarum, Geotaenium and Heterotropa could distinguish by the presence or absence of some anthochlor pigments. Other flavonoids were isolated from the selected 18 Asarum species. They were characterized as some flavonol 3- or 3,7-O-glycosides based on kaempferol, quercetin and isorhamnetin, flavone, apigenin 6,8-di-C-glycoside, flavanone, naringenin 5,7-di-O-glucoside, and xanthone, mangiferin.     

Studies in the morphology and systematics of berberidaceae

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.     

Ontogeny,function and evolution of extreme floral construction inMonimiaceae

In at least 4 genera of theMonimiaceae (Tambourissa, Wilkiea, Kibara, Hennecartia) extremely specialized flowers with a hyperstigma occur, i.e. a secretory zone in the narrow entrance of the floral cup. The mucilaginous secretion of the hyperstigma and of the carpels produces a transmitting medium for pollen tubes continuous from the mouth of the floral cup to the ovules. As to their floral morphology, the two extreme types,Hortonia andTambourissa, are connected gradually by various other genera. Possible evolutionary trends and systematic problems are outlined.     

Floral anatomy of the Styracaceae, including observations on intra-ovarian trichomes

DICKISON, W. C., 1993. Floral anatomy of the Styracaceae, including observations on intra-ovarian trichomes All eleven genera of the Styracaceae were examined with respect to floral morphology and anatomy. Floral structure and vascularization are described in detail. Flowers of the family exhibit different degrees and patterns of specialization. All Styracaceae show some degree of basal non-divergence of perianth members, forming a hypanthium that is adnate to the ovary wall to a lesser or greater extent. The extent of reduction and amplification in the number of sepals, petals, stamens, and carpels varies widely among genera, and generally the non-divergence, decrease, or increase in parts is not equally pronounced in the different whorls of the same flower. Genera cannot be readily aligned in an intergrading sequence of morphological advancement. Stamen form and anatomy is variable. A fibrous endothecium ranges from well-developed to weakly formed or absent. A nearly uniform feature of the styracaceous gynoecium is the presence of incompletely septate ovaries. The major points of variation in the floral vascular system relate to the number, mode of origin, and degree of independence of sepallary traces; degree of independence of the androecial vasculature; the level at which the common petal and petalad-stamen or sepal and sepalad-stamen bundles separate to their component parts; organization of the ventral ovarian supply; and the occurrence of ventral bundles in the style. Floral vascularization provides evidence that the family was derived from an obdiplostemonous ancestor. A unitegmic ovule is predominant in the family and starch is present in the megagametophyte of some taxa. An unusual feature of the flowers of the Styracaceae is the occurrence of stellate and lignified intra-ovarian trichomes. Numerous similarities in floral morphology and anatomy between Styracaceae and Ericales are pointed out.     

阔叶杨桐衍生胎座的发育特征(五列木科)

为观察五列木科阔叶杨桐子房中衍生胎座的发育过程,探明衍生胎座与心皮源胎座及特立中央胎座的关系,该研究采用扫描电子显微镜和体视显微镜相结合的方法,详细观察了阔叶杨桐的花芽和成熟果实。花芽采集后经FAA固定、酒精-乙酸异戊酯梯度脱水、液体CO_2干燥、扫描电子显微镜下观察;将成熟果实直接在体视显微镜下解剖观察。结果表明:阔叶杨桐花芽发育过程中,雄蕊原基发生后,5心皮快速发生,先愈合形成上部具有中轴胎座、下部是空腔的子房;接着心皮上长出胎座(心皮源胎座),在其下部空腔内与心皮相对的位置,花托顶端出现多个凸起,并逐渐愈合成半球形的衍生胎座,心皮源胎座和衍生胎座上出现多枚可育胚珠。成熟果实中,心皮源胎座和衍生胎座上均有种子,二者之间没有维管束联系。因此,衍生胎座与心皮源胎座独立发生,且晚于心皮源胎座;阔叶杨桐衍生胎座的发育过程不同于石竹科和商陆科的特立中央胎座(中轴胎座隔膜消失形成),而与杜鹃花目报春花科、假轮叶科、杜茎山科和紫金牛科的特立中央胎座类似(在花托顶端直接形成)。     

COMPARATIVE STUDIES OF FLORAL MORPHOLOGY OF THE LABIATAE

Hillson , Charles J. (Pennsylvania State U., University Park.) Comparative studies of floral morphology of the Labiatae. Amer. Jour. Bot. 46(6): 451–459. Illus. 1959.—Comparative vascular studies of 39 species of mints from 27 genera reveal 2 basic stelar patterns: those in which the dorsal carpellary bundles are terminal in origin and those in which the dorsal carpellary bundles are basal in origin. Gradations of intermediate dorsal carpellary bundle divergence exist. Steles exhibiting terminal dorsal carpellary bundles are always associated with laminal ovules and are interpreted as being primitive. Marginal ovules are associated with floral steles exhibiting basal divergence of dorsal carpellary bundles and are regarded as being advanced. Adnation of traces seems to be a more reliable character in determining phylogenetic relationships than is connation. On the basis of 3 characters, viz: (1) position of dorsal carpellary bundle divergence, (2) ovule position and (3) degree of concrescence, a phylogenetic series of the 8 sub-families of Labiatae from advanced to primitive is proffered.     

Notes on the capsule dehiscence inAcanthophyllum (Caryophyllaceae) and allied genera

The shape and the mode of dehiscence of the capsule had been regarded as good differential characters betweenAcanthophyllum and related genera.—Studies of these characters, including the shape of the ovary, in species ofAcanthophyllum, Diaphanoptera, Ochotonophila andScleranthopsis show, however, that they cannot be used as differential characters for the genusAcanthophyllum. Dedicated to Prof.K. H. Rechinger on the occasion of his 80th birthday.     

Floral anatomy of Bromeliaceae, with particular reference to the evolution of epigyny and septal nectaries in commelinid monocots

Floral anatomy is described in ten genera of Bromeliaceae, including three members of subfamily Bromelioideae, three Tillandsioideae, and four genera of the polyphyletic subfamily Pitcairnioideae (including Brocchinia, the putatively basal genus of Bromeliaceae). Bromeliaceae are probably unique in the order Poales in possessing septal nectaries and epigynous or semi-epigynous flowers. Evidence presented here from floral ontogeny, vasculature, and the relative positions of nectary and ovules indicates that there could have been one or more reversals to apparent hypogyny in Bromeliaceae, although this hypothesis requires a better-resolved phylogeny. Such evolutionary reversals probably evolved in response to specialist pollinators, and in conjunction with other aspects of floral morphology of Bromeliaceae, such as the petal appendages of some species. The ovary is initiated in an inferior position even in semi-epigynous or hypogynous species. The ovary of all so-called hypogynous Bromeliaceae is actually semi-inferior, because the septal nectary is infralocular; in these species the nectaries have a labyrinthine surface and many vascular bundles. Brocchinia differs from most other fully epigynous species in that each carpel is secretory at the apex and reproductive, rather than secretory, at the base.     

Karyological studies of four genera of theChloranthaceae

Karyological observations on 7 species and 2 varieties of 4 genera belonging to theChloranthaceae demonstrate the presence of three basic chromosome numbers within the family, i.e., x = 8 (Hedyosmum), 13 (Ascarina) and 15 (Chloranthus, Sarcandra). The karyomorphology ofChloranthus andAscarina is similar, whereasSarcandra andHedyosmum display unique characteristics. Both karyological aspects, i.e., chromosome number and karyomorphology, demonstrate remarkable diversity ofChloranthaceae and complex relationships between its genera. A distant affinity betweenChloranthaceae andPiperales is suggested.Presented at the XV International Botanical Congress Yokohama 1993, Symposium on Relationships and Evolution of Primitive Angiosperms: Multidisciplinary Approaches.     

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.     

THE FLORAL ANATOMY OF KOEBERLINIA ZUCC: SYSTEMATIC IMPLICATIONS

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.