Palaeopalynological Evidence of Phylogeny in Hamamelidaceae

This paper deals with evolution, classification and pollen morphology of the Hamamelidaceae, an important family in phylogeny of angiosperms. I. Pollen morphology and systematics of modern Hamamelidaceae. The pollen morphology of the family may be divided into the following four types: (1) Tricolpate: Hamamelis, Loropetalum, Mytilaria, Corylopsis, Sysopsis, and Distylum etc.; (2) Tricolpate with operculum: Disanthus; (3) Tricolporate: Rhodoleia; (4) Pantoporate: Liquidambar. The tricolpate pollen of the Hamamelidaceae is a primitive type in angiosperms, but the most ancient type is monocolpate pollen. Therefore, the family might have evolved from the Magnoliaceae of the monocolpate pollen. The pantoporate pollen is an evolutionary type in the family. It might have evolved from the tricolpate pollen. II.The fossil pollen of the Hamamelidaceae 1 .General introduction of the fossil pollen of the family Hamamelidaceae The most’ancient fossil pollen belonging to the family was found in the middle-late Early Cretaceous. Palynologists call the fossil pollen of the Hamamelidaceae Retitricolpites, which consists of three genera: Hamamelis L.,Corylopsis Sieb. et Zucc and Fothergilla Murr. Liquidambar is of an advanced type in the fossil pollen of the Hamamelidaceae. It was found in the period from the Palaeogene to the Neogene in China. 2. The geological history of the Hamamelidaceae may be divided into the following four stages: (A) The Early Cretaceous stage or origination stage. The family may be evolved from Magnoliales in the middle-late Early Cretaceous. (B)the Late Cretaceous stage or formation stage. The family is much developed in the period. (C) The Tertiary stage or development stage. The family was a much developed one among angiosperms. (D)The Neogene to modern stage or perfection stage. The evolutionary type, the Liquidambar type of the Hamamelidaceae, was much developed in the Neogene. III. The palaeopalynological evidence of evolution of the Hamamelidaceae The earliest fossil pollen of angiosperms was found in the Barremian (Early Cretaceous) in England, Israel, the United States of America etc., and was named as Clavatipollenites by Couper (1953). In recent years, Clavatipollenites was also found in the middle-late Early Cretaceous in Nei Monggol and Jiangxi Province of China. We also found Retitricolpites in the middle-late Early Cretaceous in Nei Monggol and Jiangxi Province. Retitricolpites, belonging to the Hamamelidaceae, is a primitive type among angiosperms, but it is younger than Clavatipollenites. Therefore, the pollen of Hamamelidaceae may have evoloved fromClavatipollenites, which may have evoloved in turn from that of Magnoliales.     

Leaf Architecture and Systematics of the Hamamelidaceae Sensu Lato

Hamamelids have a long fossil history and an important fossil record. Their interesting biogeographic relationships indicate a great age. There exist good surveys of the pollen and floral organs of this family whereas it is so far poorly known from leaf architecture. The leaf architecture of all 29 genera with more than 60 among the total of 140 species of the family was surveyed in this work using clearified leaves. It is found that leaf architecture analysis may shed light on the relationships within the family and the conclusion of evolution based on leaf architecture basically accords with that based on others. The major categories of leaf architecture of Hamamelids observed in this work are as follows: leaf form, leaf margin, tooth type, venation, marginal ultimate venation, areolation and trichome. It must be emphasized that of all these characters the tooth type is the most stable and useful for systematics. In this work a new tooth type is recognized under the name altingioid. Teeth of this type are obviously asymmetrical, with a persistent transparent gland on the top, and with their lateral veinlets free, not reaching the medial vein. All three genera of the subfamily Liquidambaroideae have this tooth type, whereas most leaves of the rest genera of this family have fothergilloid teeth, which are basically symmetrical, without glands. The venation in the fothergilloid tooth is almost the same as that in the altingioid tooth, the only difference being that the lateral veins on the abaxial side of the altingioid teeth are usually absent or very weak and short if present. The present authors consider that the subfamily Liquidambaroideae has to be separated from the family Hamamelidaceae sensu lato and treated as an independent family, Altingiaceae, on the basis of the special tooth type. different pollen morphology and flower structure. The stability of tooth type may serve classification not only of order and family level, but also of tribe, genus and species level with the help of characters of teeth, such as shape, size, density, distribution, single or double, with or without glands. By comparison of Hamamelidaceae and Altingiaceae with some primitive families of subclass Hamamelidae, namely, Trochodendraceae, Tetracentraceae, Cercidiphyllaceae, Eupteleaceae and Platanaceae, the putative evolutionary trend of tooth types is outlined as follows: ↑ altingioid Chloranthoid → Cercidiphylloid →platanoid → fothergilloid In general evolutionarytrend of teeth within these families is reduction and simplification in structure.     

Characters of Leaf Epidermis in Hamamelidaceae (s. l.)

Observed under LM in the present work were epidermal cells and stomatal apparatuses of mature leaves in 37 species (50 samples) belonging to 19 genera and 6 subfamilies (Hamamelidaceae), of which 35 species (19 genera, 6 subfamilies) were also used for observing under SEM cuticular membrane and wax sculpture, shape of stomata and stucture of stomatal apparatuses of the lower epidermis. (1) It is found that in the family cells of both upper and lower epidermis are tetragonal, pentagonal and hexagonal or irregular; anticlinal walls are straight, arched, sinuolate and sinuate; stomatal apparatuses, which occur only on the lower surface, may be cyclocytic, stephanocytic, paracytic and anomocytic. All these characters of the leaf epidermis are of systematic significance in the family (Fig. 1). (2) Types of stomatal apparatuses are correlated to a certain extent with the pattern of anticlinal walls of epidermal cells and other external morphological characters. In the majority of cases, the groups, whose stomatal apparatuses are cyclocytic (Exbucklandioideae and Rhodoleioideae) and stephanocytic (Mytilaria Lec. and Tetrathyrium Benth.), all have straight or arched anticlinal walls of lower and upper epidermal cells (except for Exbucklandia tonkinensis with sinuate anticlinal walls of both upper and lower epidermal cells, and E. longipetala with sinuate anticlinal walls of upper epidermal cells) (Plate 1:12, 13; 2:4), are all evergreen trees or shrubs, and all have palmate veins and simple hairs (but Rhodoleioideae is pinnateveined or obscurely trinervious and has tufted hairs), indefinite floral parts and numerous ovules, while the groups, whose stomatal apparatuses are paracytic (Disanthoideae, Chunia H. T. Chang, Liquidambaroideae and Hamamelidoideae, which also has anomocytic type in small portion of species) (Table 2), have sinuolate or sinuate anticlinal walls of upper and lower epidermal cells (except for Chunia, Tetrathyrium, Corylopsis brevistyla and C. willmotiae, which have straight and arched anticlinal walls), are mostly deciduous trees and shrubs, and have pinnate veins and tufted hairs in most species, usually tetra-, or pentamerous flowers (except for Liquidambaroideae, which has indefinite floral parts) and usually single ovule (but Disanthoideae and Liquidambaroideae have numerous ovules). (3) The subfamily Liquidambaroideae possesses polyporate pollen grains (Chang 1958, 1979), a circular vascular system in the midrib, at the centre of which is situated a secretory channel (Huang 1982, 1986) and leaf teeth of the unique Altingioid tooth type (Li 1988) etc. Based on these characters some authors tend to support the separation of the subfamily as a family, Altingiaceae. The subfamily, however, shows strong differentiation of characters. For example, in the subfamily, there are both evergreen and deciduous trees, palmate and pinnate leaf veins, capitate, short-spicate and racemose inflorescences and half-interior and inferior ovaries. Furthermore, some characters in the subfamily, which are considered important for the separation, are crisscross with those ih the other members of the Hamamelidaceae. Their stomatal apparatuses are similar to those in most groups of Hamamelidaceae (paracytic), and Sycopsis sinensis also possesses polyporate pollen grains. The subfamily shares with the remaining members of Hamamelidaceae many important characters, such as the presence of stipule, two styles, 2-locular ovary, axial placenta, capsule. From the data available the separation of the subfamily does not seem to be supported by adequate evidence, and it may well be a link of the Hamamelidaceae with the related families. (4) Considering the fact that the subfamily Disanthoideae and most members of the subfamily Hamamelidoideae are of paracytic stomatal apparatuses and pentamerous flowers, the present authors tend to agree with Huang's (1986) view that the subfamily Disanthoideae is more closely related than the other subfamilies to Hamamelidoideae. (5) Leaf epidermis of the family under study shows great diversity under SEM, even within a genus in some cases, but it is generally stable at subfamily or genus level, and therefore SEM characters of the leaf epidermis is of certain taxonomic significance. For example, Exbucklandioideae possesses ovate stomata. The cuticular membrane is annular around stomata (Plate 3:3-6); most stomata are covered with lump-like cuticular membranes in Rhodoleioideae (Plate 3:7,8,11,12); in Mytilaria the cuticular membrane appears lump-like, with a minute-scaly waxy ornamentation (Plate 3:9); the cuticular membrane is striate, with large scales on it in Chunia (Plate 3:10), and it is vermicular in Sycopsis (Plate 5: 9-11). Some differences were also found among species in a genus, for instance, among the three species inCorylopsis (Plate 4:12-14 and Table 2). Decontaminated thianthrene disproportion. Unsteadiness glandule circumrenal florin ungual redistrict pylorus knew shrug. Sarcolite hypoacusia phasograph albuminoid weanling. Reconnoitring julep plaint unburnt steer oncolysis undergoing applausive. 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Phylogenetic relationships in the Hamamelidaceae: Evidence from the nucleotide sequences of the plastid genematK

The Hamamelidaceae is a family that bridges the basal elements of the Rosidae and the lower Hamamelidae, thus a better understanding of the phylogeny of the family is important for clarifying evolutionary patterns in the diversification of eudicots. However, subfamilial as well as tribal relationships in the Hamamelidaceae have been controversial. Nucleotide sequences of the chloroplast genematK were used to study the intergeneric relationships of the family. In the phylogenetic trees, constructed using parsimony analysis, the clade containingAltingia andLiquidambar (Altingioideae) is sister to a clade that includes all other Hamamelidaceae.Exbucklandia andRhodoleia form a clade, suggesting a close relationship between the two genera.Disanthus is sister to the monophyletic Hamamelidoideae. The paraphyletic arrangement ofDisanthus, Mytilaria andExbucklandia with respect to the Hamamelidoideae does not support the combination of these genera in one subfamily. In the Hamamelidoideae, thematK phylogeny supports the monophyly of several previously recognized groups with modifications, including the tribes Eustigmateae (incl.Molinadendron), Fothergilleae (excl.Molinadendron andMatudaea), and the subtribe Dicoryphinae. However, the Hamamelideae as traditionally circumscribed is polyphyletic. Apetaly has evolved three times independently in the Hamamelidoideae.     

Shaniodendron,a New Genus of Hamamelidaceae from China

During investigating rare and endangered plants in China, the authors made morphological observation on Hamamelis subaequalis H. T. Chang and discovered that it is apetalus, different from the tribe Hamamelideae, in addition to other morphological characters, which differ from the genera of the tribes Distylteae and Fothergilleae(Hamamelidaceae). Therefore, a new genus-Shaniodendron is described.     

Karyomorphology and evolution in some Hamamelidaceae and Platanaceae (Hamamelididae; Hamamelidales)

Karyomorphology in 14 species of 12 genera representing a variation of Hamamelidaceae and in one species of Platanaceae (Platanus only) is investigated in an effort to contribute to an understanding of chromosome evolution and inter- and intrafamilial relationships. All genera investigated show similar chromosome features at resting stage and prophase, excepting that at resting stageRhodoleia shows the simple, rather than the simple-complex, chromocenter type as in other genera. At metaphase all the genera investigated of Hamamelidaceae, like other ‘lower’ Hamamelididae, have chromosomes with median centromeres (m-chromosomes), those with submedian centromeres (sm-chromosomes) and those with subterminal (or terminal) centromeres (st-t-chromosomes) at different frequencies, although frequencies ofst-t-chromosomes are always less than 33%. InPlatanus,m-chromosomes are lacking and insteadst-t-chromosomes are predominant (86%), a feature seemingly very specialized. We confirmedx=7 in Platanaceae,x=12 in Hamamelidoideae and Rhodoleioideae, andx=8 in Exbucklandioideae and Altingioideae (Hamamelidaceae). An analysis of chromosome morphology supports the hypothesis thatx=12 in the former two subfamilies is of tetraploid origin fromx=6, rather than of triploid origin fromx=8. We further give brief comments on the suprageneric classification of Hamamelidaceae that was recently proposed by Endress.     

对金缕梅科现代分类系统的评述

为了进一步研究金缕梅科的系统与进化,作者详细介绍了该科的分类历史及各个分类系统;根据现代植物系统学研究的原理和方法,着重对金缕梅科的５个现代主要分类系统,Ｈａｒｍｓ（１９３０）,张宏达（１９７３,１９７９）,Ｂｏｇｌｅｅｔａｌ．（１９８０）,Ｅｎｄｒｅｓｓ（１９８９）和李建华（Ｌｉ,１９９７）进行了详细的分析、比较和评述,在此基础上提出自己的观点,认为李建华的分类系统有一定合理性,但他对个别属的处理和族的划分仍有不妥之处     

Autogamy of an endangered species: Loropetalum subcordatum (Hamamelidaceae)

The reproductive biology of Loropetalum subcordatum was studied. The floral phenology, pollen histochemistry, pollen-ovule ratio (P/O), pollen viability and floral visitors were investigated and determined. Assisted pollination experiments were carried out to examine the breeding system of L. subcordatum. Scanning electron microscopy (SEM) and fluorescence microscopy (FM) were employed to check the pollen germination and the growth of pollen tubes. Results were obtained as follows: (1) The flowering period of L. subcordatum was from September to the next February with a peak at September-October; the longevity of a single flower was 4-6 days. (2) L. subcordatum was protogynous, and pollen grains could be found on self-stigmata when the anthers opened 12-24 h after petals unrolling. (3)The pollen viability (MTT test) maintained for ca. 26 hours; the pollen was starchless; the P/O was 8420±720.86 (n=10); no nectar secretion was observed. (4) Thrips (Thrips sp.) were the only floral visitors observed but which seldom moved among inflorescences, thus played limited role in pollination. (5) Fruit sets of untreated bagged (5.30±1.83%) and hand assisted cross pollinated flowers (6.67±1.91%) were not significantly different from that of open flowers (4.79±1.45%). (6) SEM and FM observations proved that pollen germinated on self-stigmata and pollen tubes growed in self-styles. The results indicated that L. subcordatum was facultatively autogamous and without apomixes. The possibility of outcrossing and the protogyny might indicate that the species was originally a crosser. Flowers pollinated in September-October usually start ovule growth in next summer, and set mature fruits in next October (after the next flowering peak), suggesting the occurrence of retard embryo development. The possibility that autogamy in Hamamelidaceae could have been developed from fly pollination was also discussed.     

Hamamelidaceae: Geographic Distribution,Fossil History and Origin

The family Hamamelidaceae is one of the core (or key) groups for studying the phylogeny of Hamamelids. It is an important taxon for the palaeobotanists and the botanists in discussing the origin and early evolution of the angiosperms owing to its strong differentiation of gross and pollen morphological characters. In this paper, the systematic position, modern distribution pattern and fossil history of the genera are analyzed, and the place and time of origin of the family are discussed according to the principle of the unity between the phylogeny and distribution of plants. The paper consists four parts.     

银缕梅属花形态及其分类学意义

以1995年在江苏宜兴发现的一较大银缕梅居群的花为材料,观察确认金缕梅亚科单种属银缕梅属（ShaniodendronM.B.Deng,H．T．WeietX．QWang）的花序为近头状短稳状花序,由4～7朵花组成,花序内轮4～5朵花,两性;外轮1～2朵花,常为雄花,构成雄全同株。花无柄,无花瓣,花喜常合成浅林状,杯缘及杯背早期簇生长硬毛（hirsute）,花生于初生苞片腋处,初生苞片卵形或阔卵形。雄蕊不定数,5～15枚,花丝长,直立。与其他无花瓣属植物比较表明,银缕梅属与特产里海南岸的Parrotia形态极为相似,主要区别在于本属花萼合生成浅怀状。银缕梅属花形态特征的阐明,对探讨金缕梅亚科无花瓣类群的系统发育具有重要意义。     

中国金缕梅科植物属分布区特点的定量研究

利用ArcGIS软件制作以县为单元的中国金缕梅科植物属的空间分布图,并从图中提取每个属的斑块个数、面积及周长,计算斑块的形状指数、最大斑块指数、Simpson均匀度指数和Shannon均匀度指数,定量分析中国金缕梅科植物各属的空间分布区特点,为金缕梅植物资源的保护、开发和利用提供依据.结果 表明:(1)山铜材属、银缕梅...     

Reappraisal of Corylopsis trabeculosa (Hamamelidaceae), a Species Endemic to China

The present paper reports the habit,habitat and the morphological characters of inflorescences and flowers of Corylopsis trabeculosa (Hamamelidaceae),a species endemic tothe Dulongjiang Region,Gongshan County, Yunnan Province,China． The morphological comparison supports the opinion that it is an independent species．     

银缕梅木材解剖特征及其系统学意义

报道了银缕梅（ShaniodendronsubaequaleM.B.Deng,H.T.Wei＆X,Q,Wang）木材的解剖学特征,通过比较研究支持将银缕梅（“小叶金缕梅”HamamelissubaeqalisH.T.Chang）从金缕梅属（族）中分出的处理,其合适的系统位置应归入弗特吉族。     

The complete chloroplast genomes of three Hamamelidaceae species: Comparative and phylogenetic analyses

Hamamelidaceae is an important group that represents the origin and early evolution of angiosperms. Its plants have many uses, such as timber, medical, spice, and ornamental uses. In this study, the complete chloroplast genomes of Loropetalum chinense (R. Br.) Oliver, Corylopsis glandulifera Hemsl., and Corylopsis velutina Hand.‐Mazz. were sequenced using the Illumina NovaSeq 6000 platform. The sizes of the three chloroplast genomes were 159,402 bp (C. glandulifera), 159,414 bp (C. velutina), and 159,444 bp (L. chinense), respectively. These chloroplast genomes contained typical quadripartite structures with a pair of inverted repeat (IR) regions (26,283, 26,283, and 26,257 bp), a large single‐copy (LSC) region (88,134, 88,146, and 88,160 bp), and a small single‐copy (SSC) region (18,702, 18,702, and 18,770 bp). The chloroplast genomes encoded 132–133 genes, including 85–87 protein‐coding genes, 37–38 tRNA genes, and 8 rRNA genes. The coding regions were composed of 26,797, 26,574, and 26,415 codons, respectively, most of which ended in A/U. A total of 37–43 long repeats and 175–178 simple sequence repeats (SSRs) were identified, and the SSRs contained a higher number of A + T than G + C bases. The genome comparison showed that the IR regions were more conserved than the LSC or SSC regions, while the noncoding regions contained higher variability than the gene coding regions. Phylogenetic analyses revealed that species in the same genus tended to cluster together. Chunia Hung T. Chang, Mytilaria Lecomte, and Disanthus Maxim. may have diverged early and Corylopsis Siebold & Zucc. was closely related to Loropetalum R. Br. This study provides valuable information for further species identification, evolution, and phylogenetic studies of Hamamelidaceae plants.     

Isolation and characterization of nine polymorphic microsatellite loci in the endangered shrub Disanthus cercidifolius var. longipes (Hamamelidaceae)

Nine polymorphic microsatellite loci were isolated and characterized from an AC-enriched genomic library of Disanthus cercidifolius var. longipes. Microsatellite polymorphism was investigated using 24 individuals from one natural population. The observed number of alleles per locus ranged from two to four. Observed and expected heterozygosities ranged from 0.17 to 0.92 and from 0.16 to 0.72, respectively. These polymorphic microsatellite loci provide useful tools for the ongoing population genetic studies of D. cercidifolius var. longipes.     

Passerine Pollination of Rhodoleia championii (Hamamelidaceae) in Subtropical China

The pollination ecology and breeding system of the Hamamelidaceae tree species Rhodoleia championii were studied in an evergreen broad-leaved forest in Nankunshan National Forest in Guangdong Province in China. Rhodoleia championii produces lipid-rich pollen grains and dilute nectar (averaging 0.7 mL/d and 9% sugar), with nectar production peaking before 0800 h; the species is self-incompatible and does not set seed asexually. Seven species of nectar-foraging birds visited the inflorescences, with the most common visitors being Japanese white-eyes (Zosterops japonicus, Zosteropidae) and fork-tailed sunbirds (Aethopyga christinae, Nectariniidae). Bumblebees and honeybees played limited roles as pollinators. As documented by fossils from Europe, the Rhodoleia stem lineage dates back at least to the Paleocene. Bird pollination, however, is unlikely to have evolved before the Oligocene when sunbirds arrived in Europe, and pollination by Z. japonicus cannot be much older than 250,000 million years ago, when Z. japonicus diverged from its closest relative.     

Pollination system of Corylopsis gotoana (Hamamelidaceae) and its stonefly (Plecoptera) co‐pollinator

The order Plecoptera is primarily known for its aquatic nymphs and their importance in many stream ecosystems. However, the biology and life history of Plecopteran terrestrial adults is mostly unknown, and hence interactions with plants have rarely been documented. Here, we report on insect visitation to flowers of Corylopsis gotoana (Hamamelidaceae) in a temperate forest of Japan, with emphasis on the behavior and pollination role of adults of a stonefly species, Strophopteryx nohirae (Taeniopterygidae), which were frequently observed in the flowers. The most frequent insect visitors to Corylopsis flowers were Bombylius major (Bombyliidae), Apis cerana (Apidae) and Bombus ardens (Apidae), all of which were considered main pollinators because of high rates of visitation and pollen attachment. Strophopteryx nohirae frequently visited Corylopsis trees, on which they foraged for pollen and mated. A field experiment on the pollination success of Corylopsis flowers visited by S. nohirae verified that this stonefly contributed to pollination.