Simsia

Abstract: Anthochlors (chalcones and aurones) are found in a number of plant families including the Compositae. Within this family they were once thought to occur only in the subtribe Coreopsidinae of the tribe Heliantheae. More recent studies show them to occur also in the tribes Cardueae, Eupatorieae, Helineae, Inuleae, and Lactuceae. This has suggested that anthochlors are no longer good taxonomic markers for the Coreopsidinae. A survey of 69 of approximately 210 genera of the Heliantheae shows anthochlors present only in the Coreopsidinae except for Helianthus, Simsia, Tithonia, and Viguiera, closely related genera of the subtribe Helianthinae. Of the 32 genera of the Coreopsidinae recently recognized, 30 were surveyed from available material and all contain anthochlors except Guardiola and Venegasia. The results indicate that, despite some variation, anthochlors are still good taxonomic markers for the Coreopsidinae. This represents the only case within the family in which a particular type of flavonoid is taxonomically diagnostic at the subtribal level. THE WORK of Geissman and co-workers some 25 years ago (e.g., Seikel and Geissman, 1950a; Geissman and Harborne, 1955; Geissman, Harborne and Seikel, 1956; Harborne and Geissman, 1956) dealt primarily with the isolation and structural elucidation of the socalled anthochlor compounds (chalcones and aurones) from members of the genus Coreopsis (Compositae). At about the same time, Shimokoriyama (Shimokoriyama and Hattori, 1953; Shimokoriyama, 1957) was also investigating anthochlors in Coreopsis as well as looking at a species in the closely related genus Cosmos. Both taxa are members of the subtribe Coreopsidinae, tribe Heliantheae, of the Compositae. The compounds were isolated from floral tissues where they are important as yellow pigments. It is now known that anthochlors occur in a number of plant families other than the Compositae (Seikel and Geissman, 1950b; Geissman and Harborne, 1955; Harborne, 1962, 1966; Wong, 1966; Bohm, 1975; Nigam and Saxena, 1975; Adityachaudhury et al., 1976; Gupta, Seshadri and Sood, 1976; Imperato, 1978; Maradufu and Ouma, 1978; and Water1 Received for publication 7 January 1980; revision accepted 28 May 1980. Appreciation is expressed to: David Giannasi, formerly of the New York Botanical Garden, William Grime of the Field Museum of Natural History, Harold Robinson of the Smithsonian Insitution, and B. L. Turner of The University of Texas at Austin, for help in selecting herbarium material from NY, F, US, and TEX, respectively, for the chemical analyses; Marvin Roberts and John La Duke for unpublished data on Megalodonta and Tithonia, respectively; and NSF for financial support under Grants DEB77-21727 to D. J. C. and DEB-75-20819 to T. F. S. man and Pootakahm, 1979), and they have been detected in species of Compositae other than members of the Coreopsidinae (Harborne, 1966, 1977a; Bohm, Saleh and Ornduff, 1974; Harborne and Smith, 1978; see Bohm, 1975 and Harborne, 1977b, for reviews). Anthochlors have been reported from ferns (Star and Mabry, 1971) and from three species of bryophytes (Markham and Porter, 1978). The early chemical studies on chalcones and aurones (Gertz, 1938; Geissman, 1941a, b; Geissman and Heaton, 1943, 1944), completed largely on genera of Coreopsidinae, prompted Cronquist (1955) in his review of the phylogeny and taxonomy of the family to state (p. 486): "Within the Compositae, their very wide distribution in and usual restriction to the Coreopsidinae furnish further evidence of the naturalness of that subtribe. " Because of the more recent chemical studies which show a broader occurrence of anthochlors within the Compositae and in other families (e.g., Bohm, 1975, for a review), in a new overview of the systematics of the family Cronquist (1977) states that (p. 149): "Now it appears that the concentration of numbers in the Coreopsidinae was an artifact of the selection of materials for study. These pigments are well scattered through the Heliantheae, at least, and they occur infrequently in a wide range of other families as well." Despite the fact that chalcones and aurones are now known to be more widely distributed in the plant kingdom than was once thought, they still do appear to be characteristic of the Coreopsidinae. Anthochlors also have been useful for systematic purposes within several

Abstract: Chromosome counts of Compositae are reported from Mexico, Central America, Ecuador, and Chile. First counts are reported for 20 species in Baccharis, Calea, Erigeron, Eupatorium, Heliopsis, Isocarpha, Liabum, Monactis, Pinaropappus, Senecio, Sigesbeckia, Simsia, Spilanthes, Verbesina, and Viguiera. Additional counts also are provided for 65 populations of taxa counted previously, of which 10 are new numbers. The systematic implications of certain of these counts are discussed. DURING RECENT EXPEDITIONS from our laboratory to Latin America to collect genera of Compositae for revisionary studies, miscellaneous taxa of the family also have been collected. In addition to herbarium material, floral buds have been obtained for chromosomal studies. These have yielded new counts as well as confirmatory data for other taxa known from only one or a few reports. Two previous studies of this type from our laboratory already have been published (Keil and Stuessy, 1975, 1977). The materials and methods involving conventional squash techniques of buds for meiotic stages are outlined in Keil and Stuessy (1975); our methods here differ only in the use of Snow's stain (Snow, 1963) rather than acetocarmine. All voucher specimens are on deposit in the herbarium of The Ohio State University (OS).

Abstract: Simsia (Compositae-Heliantheae) comprises annuals, herbaceous perennials, suffru tescent perennials, and shrubs. It occurs throughout tropical America from sea level to 3000 m. This study is based on comparative morphology, including extensive field studies and observations in the greenhouse, phenetic studies, crossing experiments, and cytology. Eighteen species including seven varieties are recognized. Two species, S. santarosensis and S. villasenorii, are newly described. The following new combinations are proposed: S. annectens var. grayi, S. foetida var. grandiflora, S. foetida var. jamaicensis, S. foetida var. megacephala, and S. foetida var. panamensis. Twenty species and varieties are predominantly self-incompatible and outcrossers; three species are self-compatible (or apomictic) and possibly inbreeders. Meiosis is normal in most of the F1 hybrids produced from outcross ing species but irregular in F1 hybrids involving a self-compatible species. Chromosome numbers are uniformly n = 17. Counts are reported for the first time for the following: S. annectens var. annectens, S. chaseae, S. foetida var. panamensis, S. holwayi, S. molinae, S. santarosensis, S. setosa, S. tenuis, and S. villasenorii.

Abstract: We analyze the latitudinal shift in the onset of synchronous flowering in the woody genera Montanoa and Simsia (Asteraceae) between Mexico (28° N) and the Equator, where it cannot be caused by declining day length. Synchronous flowering of >100 Montanoa quadrangularis trees was observed during two consecutive years near Cali, Colombia (4° N). Analysis of herbarium specimens yielded flowering periods for 21 Montanoa species and 18 Simsia species between 4 and 28° N. Daily insolation is a function of day length and the angle at which the sun’s rays strike the earth. Between Mexico and Colombia (4° N), the maximum of insolation gradually shifts from the summer solstice to the autumn equinox. In parallel, flowering of Montanoa and Simsia starts progressively later between July and November, during the period of declining insolation. Near the Equator, there are two periods of declining insolation, and correspondingly, two flowering periods. Thus, at all tropical latitudes, flowering time of Montanoa and Simsia is highly correlated with declining insolation. The seasonal decline in daily insolation, rather than in photoperiod, apparently induces synchronous flowering of Montanoa and Simsia at the same time each year.