Nearly half of the species in the large genus Saxifraga belong to Saxifraga sect. Ciliatae, a largely Sino‐Himalayan taxon. We report here that evidence from chloroplast DNA sequences (psbA‐trnH, trnL‐F) and from nuclear sequences (ITS) indicates that this section is monophyletic and composed of at least three main lineages, corresponding to (1) a clade made up of species from S. subsect. Gemmiparae, subsect. Cinerascentes, subsect. Flagellares and subsect. Hemisphaericae, in which the last three subsections are nested in the first; (2) a clade of species belonging to S. subsect. Rosulares (including S. subsect. Serpyllifoliae); and (3) a clade of species belonging to S. subsect. Hirculoideae. Species relationships in S. subsect. Rosulares and subsect. Hirculoideae are not well resolved. A molecular clock analysis indicates that the diversification of S. sect. Ciliatae into its three lineages dates from ca. 9.48 Ma, coinciding with orogenic events associated with one of the most important phases of uplift of the Qinghai‐Tibet Plateau. Extensive diversifications within S. subsect. Rosulares and subsect. Hirculoideae have been more recent (ca. 4.51 Ma and 2.12 Ma, respectively), again correlated with Qinghai‐Tibet Plateau uplift events and, in the case of S. subsect. Hirculoideae, have occurred at a rate comparable to that seen in the radiation of Hawaiian fruit flies.
Details of leaf venation in 150 species of Saxifraga L. representing all 13 sections are reported. Three main patterns were observed: palinactinodromous, acrodromous and camptodromous. Species with lobed leaves have palinactinodromous patterns, whereas those with entire leaves are acrodromous or camptodromous. Thus species from sections Heterisia, Irregulares, Cymbalaria, Cotylea and Mesogyne are palinactinodromous; species from sections Saxifraga, Ciliatae, Bronchiales and Trachyphyllum, in which some have lobed and some have entire leaves, are either palinactinodromous or acrodromous, according to the leaf margin; species from sections Ligulatae and Porphyrion, whose hydathodes secrete calcium bicarbonate, have camptodromous venation. Intermediate states occur in section Gymnopera (between palinactinodromous and camptodromous) and in section Porphyrion subsection Oppositifoliae and section Xanthizoon (intermediate between acrodromous and camptodromous). The pattern of distribution across the genus and selected outgroups shows that the ancestral state is likely to be palinactinodromous.
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In the Flora of China account of Saxifraga mengtzeana Engl. & Irmsch., eight synonyms were attributed to it and one variant, recognized as Saxifraga epiphylla Gornall & Ohba, was split from it. This study reevaluates the taxonomic status of some of the synonyms and of the segregated species in light of new evidence presented here. Morphological and molecular evidence demonstrate that collections from northwestern Yunnan and Sichuan are genetically differentiated from those in southeastern Yunnan and neighboring Guangxi. Observations in the field and in cultivation show that the peltate petiole attachment diagnostic of S. mengtzeana var. peltifolia Engl. & Irmsch. is developmentally labile. Similar observations combined with molecular data show that viviparous phenotypes, formerly treated as S. epiphylla, although largely under genetic control, occur sporadically throughout the ranges of both northern and southern taxa. Collections from northwestern Yunnan and Sichuan are best recognized as Saxifraga geifolia Balf.f., whereas those from southeastern Yunnan and neighboring Guangxi are S. mengtzeana. Peltate-leaved variants of the latter are given no status and are relegated to complete synonymy. Viviparous phenotypes of S. mengtzeana and S. geifolia are recognized at the rank of forma.
Details of exine morphology (SEM studies of 132 species) and anatomy (TEM studies of 25 species) of Saxifraga are reported. The variation observed was compared with that found in an earlier survey. We suggest modifications to known types and subtypes and the addition of new ones, making a total of nine exine types and subtypes in Saxifraga. Taxonomic conclusions include the following. A novel exine type (Type 2.3), in which the single tectum has numerous microchannels, is a putative synapomorphy for sects. Heterisia and Irregulares. At least three species from sect. Ciliatae, viz., S. lychnitis, S. oresbia from ser. Lychnitidae, and S. nigroglandulifera from ser. Nutantes, have a novel type with a perforate-reticulate or perforate-rugulate tectum. Species from the rest of the section are uniformly finely striate. Section Saxifraga has Type 2.1, with a single tectum, Type 4.3, with a double tectum, and Type 2.2, which is intermediate to various extents. The origin of Types 2.1 and 2.2 from Type 4.3 is suggested. Within sect. Saxifraga subsect. Triplinervium, S. wahlenbergii is unique in possessing pollen with a secondary tectum (Type 4.3), resembling the exine of S. androsacea in subsect. Holophyllae. On this and other grounds, we support the transference of S. wahlenbergii to the latter subsection. Himalayan species with opposite rather than alternate leaves that were formerly assigned to sect. Porphyrion subsect. Oppositifoliae, have exines with supratectal ornamentation similar to that in subsect. Kabschia; in this respect they are unlike the European species with opposite leaves, which lack this ornamentation. Among the species with chalk-glands, exines lacking supratectal ornamentation are restricted to European species, viz. those in sect. Porphyrion subsects. Engleria and Oppositifoliae, and S. florulenta, offering morphological support for the transfer of the latter species to sect. Porphyrion. Saxifragella is recognised as a new section of the genus.
The high-speed railway infrastructure maintenance is the key to ensure the safe operation of the railway. The technical characteristics and advantages of Beidou Navigation Satellite System (BDS), Geographic Information System (GIS), and Remote Sensing (RS) are analysed for integrated application based on the practical application of professional engineering infrastructure monitoring, equipment inspection, disaster prevention and warning, workers management and time synchronization, and the solution of intelligent monitoring system for high-speed railway infrastructure maintenance was proposed. And this system supports visual display of vector and electronic map, status query of workers, trains, equipment and infrastructure for remotely monitoring, detecting and managing, which can provide low-cost, reliable and accurate information services for the security monitoring and management of the high-speed railway infrastructure maintenance.
Saxifraga viridipetala Z-X. Zhang & Gornall (Saxifragaceae) is described as a new species. Originating from south-western Sichuan province in China, morphological and molecular evidence (based on chloroplast trnL-F and nuclear ITS DNA sequences) indicate that S. viridipetala is closely related to S. gemmipara, in section Ciliatae. The new species can be diagnosed by its narrowly elliptic, pale green petals spotted purple in the proximal 4/5 part.
Saxifraga minutissima D.S.Rawat, a new and extremely small species of Saxifraga (Saxifragaceae), is described from the Garhwal Himalaya, India. It differs from all other species of Saxifraga, except Saxifraga bicuspidata, in having five stamens and lacking petals. It can be distinguished from Saxifraga bicuspidata in having leaves and sepals entire. The finely striate pollen exine pattern of Saxifraga minutissima indicates that the species belongs to Saxifraga section Ciliatae. Its prostrate, axillary leafy shoots and lack of crisped, rufous hairs strongly suggests a place in Saxifraga subsection Serpyllifoliae, where one of its closest relatives may be Saxifraga stella-aurea.
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