Abstract: Lysimachia, one of the largest genera in Primulaceae, has received  considerable attention from many authors and was intensively studied.  Klatt (1866) in his well- illustrated monograph described forty-five species in nine sections.  Knuth in Engler's Pflanzenreich (1905) recognized 110 species and divided them into sixteen sections. Handel-Mazzetti (1928), in a revision of the Chinese species, emumerated 147 species in the whole world, among them 83 species are from China.  He also proposed a new system by subdividing this genus into five subgenera and 18 sections. He was the first author to give a due emphasis to the floral structure, especially to the nature of androecium. We realize that his system seems to be more natural than all of the pre- vious ones; though not without faults the phylogenetic trend of this genus has been generally elucidated (fig. 1). In this paper, the basic idea of Handel-Mazzetti was adopted, but some important alternations have been made for our systematic arrangements: 1.  With a marked increase of species discovered recently in our country and ample materials now at our disposal, we find that the previously accepted distinction between the subgenus Idiophyton and the sect. Apodanthera of subgenus Lysimachia seems to be ambiguous and impossible to demarcate clearly.  The apically clustered leaves and the lateral racemes prove to be no longer peculiar to L. insignis Hemsl. alone but in com- mon with at least two other species in the sect. Apodanthera.  As to the indehiscent capsule, it occurs not infrequently in species  belonging  to  the  sect. Apodanthera. Together with these characters, there are even more primitive features of morphologi- cal significance such as ligneous stem, short filaments, large basifixed anther mostly dehisced by apical pores that have never been found in any other group of this genus. Consequently, we suggest that Handel-Mazzetti's subgeneric conception of Idiophyton should be amplified to include the sect.  Apodanthera. 2.  Owing to the undue emphasis given by previous authors on the flower colour as the major criterion to distinguish the subgen. Palladia from subgen. Lysimachia and neglecting a number of other characters of equal taxonomical importance, the white flowered species L. huitsunae Chien has long  been  erroneusly  placed  in  subgen. Palladia. After a careful examination, we find that it agrees in all respects with the species of subgen.  Lysimachia morphologically. Furthermore, it bears a strong resem- blance both in habit and floral features to L. omeiensis Hemsl. and L. hypericoides Hemsl. To be sure, it should be a member of Handel-Mazzetti's subsect. Hypericoideae which we reduced as a series of sect. Nummularia. Having transferred the white flowered species L. huitsunae Chien to, and excluded the sect.  Apodanthera from this subgenus, we then had to amend the circumscription of Handel-Mazzetti's subgen. Lysimachia.   3.  As a section, Rosulatae comprises only two species indigenous to the coast region of south China.  Handel-Mazzetti put it together with the Hawaiian section Cilicina to form a subgenus Lysimachiopsis. But, we can hardly find out any tenable characters to support such a relationship. These two restricted and isolated groups are lacking evidence either in phytogeographical affinities or in their flower features and their habit. In view of the fact that the section Rosulatae is closely related to Asian yellow flowered groups, we think there are reasons for transfering it to the subgenus Lysimachia.   4.  Morphological evidence shows that L. crispidens Hemsl. is a more specialized and isolated species in this genus.  Its diagnostic characters are: rosulate leaves, scape- like stem, long corolla tube and its unique heterostylandra which may indicate the origin of heterostyly in other advanced groups of Primulaceae.  Phylogenetically, this species may also represent the topmost twig of one of the evolutional lines in this genus. It is more reasonable to treat this monotypic section Heterostylandra with subgeneric rank.   In the present study, Lysimachia from China are classified into 5 subgenera with 122 species and 20 varieties in which 24 species and 5 varieties are as new.   In regard to the geographical distribution, Lysimachia occurs all over the world except northern Siberia, Greenland, northern  Canada,  Alaska  and  New  Zealand. Although the total range of the genus as a whole may be said as worldwide, the separate subgenera or sections are more restricted in distribution. As shown in Table I. the center of diversity of the genus as well as that of the distribution proves apparently to be in China. Out of a total of about 180 species ascribed to this genus, 122 are from this country.  In addition, most of its subgenera and sections are endemic here. It is worth mentioning that the species endemic to China now are up to 110 in number. Furthermore, it may be seen that starting from  this center the number of species becomes less and less as they proceed towards different directions, and in particular the primitive sections and species disappear rapidly (fig. 2). However, the distribution pattern of species over the whole area of our country is uneven.  Lysimachia has scarcely ever been  found  in  northern  Tibet,  Qinghai, Xinjiang, Gansu and Nei Monggol, and only a few species occur in northern and north- eastern China.  The majority of the species inhabit regions below 32°N. Lat.  The greatest concentration of the species of this genus appears in the following provinces, such as Yunnan, southern Sichuan, western Guizhow and Guangxi.  We have found that the great abundance of the species and well-known taxa of phylogenetical impor- tance are all existing in this region, and the representatives of more primitive taxa are also much richer here th