Systematic Study Of The Genus Lysimachia From Anhui

26 species representing 3 subgenera in the genus of Lysimachia,Primulaceae,from Anhui,were surveyed with respect to grass morphology,micromorphology,palynology,and cytology．All data obtained were subj ected to cladistic analysis。Onthe basis of these morphological characters,the phylogenetic relationship of taxainvolved was inferred,and furthermore all the species were taxonomically revised。The results are as follows: : The rnicrocharacteristics of leaf and seed surface in this genus were investigatedby means of light microscope(LM)and scanning electron microscope(SEM)for thefirst time．The results show that the features of leaf surface are fairly constant withinspecies and can be used as a diagnostic character for separating species．There areremarkable differences in the morphological features of seed surface between subgen．Palladia and subgen. Lysimachia,which might have significant taxonomicimplications at subgenus level。 Pollen morphology and wall structure of 24 species of this genus were observed by means of LM,SEM and transition electron microscope(TEM)。The pollen grainsof Lysimachia are tricolporate,spheroidal,subspheroidal,prolate-spheroidal or prolate,P／E ratios 0．97-1.65,small(the smallest 10.0×8.5gm in L．capillipes)to mediumsized(the largest 30.4×30.1 gm in L. congestiflora)．Equatorial view elliptic or circular．Polar view circular or triangular,angles obtuse．Ectoaperture-colpus,mostlylong with tapering ends．Endoaperture-colpus lalongate,short with tapering ends or splitting at ends,giving a characteristic H-shaped configuration,in some species may meeting laterally,producing a continuous equatorial band．Exine variable in thickness,from 0。5pm to 1.5um. Sexine about equal to or thicker than nexine。Columellaeindistinct or poorly developed with only small irregular granules,to well developed．Ornamentation verrucous-foveolate,nearly smooth or cerebroid with scattered puncta,to reticulate。Based on the characteristics of the size and shape of pollen grains,especially on the wall structure and ornamentation of sexine,4 pollen types are recognized, i．e. Capillipes-type,Heterogenea-type,Huitsunae-tupe and Christinae-type．A key to them was provided．The 4 pollen types of Lysimachia in Anhui have been a~anged in the evolutionary sequence,of which the Capillipes-type,possessing small pollen grains,with verrucous-foveolate,imperforate,onlypartially-differentiated(i．e．1acking a Columellae interstitium)exine,has beenconsidered as the most primitive pollen type,and the Christinae-type withwell-developed columellae and reticulate ornamentation,has been regarded as a fairlymore specialized type．Combined with the morphology of the flowers,theevolutionary tendency of this genus can be deduced as follows: The chromosome numbers and karyotypes of 8 taxa in this genus were also examined．It is reported for the first time that L．patungensis has the karyotype of 2n=24=8m+6sm+8t+2T；L．patungensisf glabrifolia of 2n。24=4m+8sm+8st+4t；L． congestiflora of 2n=24=2m+4st+18t；and the chromosome number of L． pseudo-henryi is 2n=22．1 8 species in this genus,which previously reported,were also cytologically analyzed．The results show that the karyotype asymmetry in subgen． Lysimachia is higher than that of subgen．Pallidia．considered the microcharacteristics of seed surface and pollen grains,the conclusion that the evolutionary level of subgen． Lysimachia is higher than that of subgen。Palladia can be easily reached． As possessing procumbent stem,opposite leaves,singular and axillary follower,L．sp．1 was regarded previously as one extreme variant of L．christinae．Withcomparative study of the variation patterns of these two entities at the populmion level,it was reveled that:(1)The length of pedicel of L．sp．l usually longer than th...