This book focuses on the morphology, the exine omamentation, and the associated evolutionary trends of crabapple pollen and anatomical developmental patterns. To examine the genetic evolutionary patterns of crabapple pollen traits, we constructed an interval distribution function based on characteristic pollen parameters and used a binary trivariate data matrix (Xi Yi Zi) to reflect the exine omamentation regularity of the pollen. Our findings should inform the taxonomic status of the Malus sp. Pollen electron micrographs from a total of 26 species and 81 cultivars of Malus were recorded in this book. All 107 figures and 642 scanned pollen images constitute primary data obtained by the authors. The images in this book are clear, threedimensional, and aesthetically pleasing. They are accompanied with text descriptions and provided a method for the indication of the different types of information that can be expected. This book can provide a reference for researchers, especially plant breeders. These people need to know the pollen structure and their compatibility for further breeding. In doing so, it has much better opportunity to produce new taxa. The research methods in palynology are also a great reference for other plant taxa.

1 Pollen Morphological Characteristics of Ornamental Crabapples
1.1 Significance of the Study of Crabapple Pollen Morphology
1.2 Observation Methods for Crabapple Pollen Phenotypes
1.3 Pollen Morphological Characteristics of Ornamental Crabapples
1.4 Analysis of Pollen Morphology Traits of Crabapple
1.4.1 Stability of Pollen Phenotypic Traits
1.4.2 Analysis of Intrapopulation Variability of Phenotypic Traits in Crabapple Pollen
1.5 Chapter Summary
2 Evolutionary Law for Ornamental Crabapple Pollen Traits
2.1 Evolutionary Research Background on Plant Pollen Traits
2.2 Study Methods for Investigating the Evolution of the Phenotypic Traits of Crabapple Pollen
2.2.1 Analysis of the Evolutionm'y Relationship of Pollen Between Species from the Malus
2.2.2 Analysis Methods for Assessing the Trend of Evolution Between Cultivars and Species
2.3 Evolutionary Relationships of Crabapple Pollen Phenotypic Traits
2.3.1 The Evolutionary Relationships of the Pollen Phenotype
Traits of Malus Species Based on Classical Taxonomy
and Molecular Evolutionary Trees
2.3.2 Evolutionary Trends of Pollen Phenotypic Traits
of Natural Species and Cultivars of Crabapples
Based on Boxplot Analysis
2.3.3 Evolutionary Trends of the Pollen Phenotypic
Traits of Natural Species and Cultivars of Crabapples
Based on Frequency Distribution Characteristics
2.4 Chapter Summary
3 Evolutionary of Pollen Ornamentation in Ornamental Crabapples
3.1 Research Background on Plant Pollen Ornamentation Evolution
3.2 Quantitative Analysis Methods for the Evolution of Crabapple Pollen Ornamentation
3.3 Evolutionary Trend of Pollen Ornamentation in Ornamental Crabapples
3.3.1 Distribution Characteristics of the Ornamentation Patterns of Crabapple Germplasm Pollen
3.3.2 Pollen Ornamentation Evolution in the Populations of Species and Cultivars
3.3.3 Evolution of Pollen Ornamentation Patterns in Parental and Progeny Populations
3.4 Chapter Summary
4 Ultrastrueture Observation of M. halliana Pollen During Development
4.1 Research Background of M. halliana Pollen Development
4.2 Mixed Bud Morphological and Developmental Observation in M. halliana
4.3 Ultrastructural Observations of M. halliana Pollen Development
4.3.1 Initial Differentiation Stage of the Anthers
4.3.2 Sporogenesis
4.3.3 Formation of Microsporocytes
4.3.4 Meiosis
4.3.5 Mononucleated Microspore Stage..
4.3.6 Pollen Maturation Stage
4.4 Ultrastructural Observations of Anther Wall Formation in M. halliana
4.4.1 Sporogenesis
4.4.2 Microsporocyte Formation Stage
4.4.3 Meiosis
4.4.4 Pollen Maturation Stage
4.5 Anatomical Causes of Pollen Abortion in Monopetalous M. halliana
4.6 Chapter Summary
5 Electron Microscopic of Crabapple Pollen
5.1 M. angustifolia
5.2 M. baccata
5.3 M. domestica vat, binzi
5.4 M. floribunda
5.5 M. fusca
5.6 M. honanensis
5.7 M. ioensis
5.8 M. mandshurica
5.9 M. micromalus
5.10 M. niedzwetzloe'ana
5.11 M. ombrophila
5.12 M. platycarpa
5.13 M. prunifolia
5.14 M. pumila
5.15 M. robusta
5.16 M. rockii
5.17 M. sieversii
5.18 M. spectabilis
5.19 M. sylvestris
5.20 M. toringoides
5.2 l M, tschonoskii
5.22 M. turkmenorum
5.23 M, yunnanensis
5.24 M, 'Abundance'
5.25 M, 'Adams'
5.26 M. 'Almey'
5.27 M, 'Ballet'
5.28 M, 'Brandywine'
5.29 M. 'Butterball'
5.30 M. 'Cardinal'
5.31 M. 'Centurion'
5.32 M. 'Cinderella'
5.33 M. 'Cloudsea'
5.34 M. 'Coralburst'
5.35 M, 'Darwin'
5.36 M. 'David'
5.37 M. 'Dolgo'
5.38 M. 'Donald Wyman'
5.39 M. 'Eleyi'
5.40 M. 'Everest'
5.41 M. 'Fairytail Gold'
5.42 M. 'Firebird'
5.43 M. 'Flame'
5.44 M. 'Furong'
5.45 M. 'Golden Hornet'
5.46 M. 'Golden Raindrop'
5.47 M. 'Gorge