Embryology of Calenduleae (Compositae)

Microsporangial conditions, macrosporogenesis, embryo sac development and in some species endosperm formation have been studied in 5 species of Dimorphotheca Vaill. ex Mnch, 2 species of Castalis Cass., 16 species of Osteospermum L., 6 species of Calendula L., 1 species of Gibbaria Cass., and 1 species of Chrysanthemoides Tourn. ex Fabr.
The microsporangial wall consists of four different layers of cells. Miocrospore formation is simultaneous. The tetrads are mostly arranged in tetrahedrals. A tapetal periplasmodium develops.
The archespore of the macrosporangium is in most cases 1-celled, sometimes 2-or many-celled. The meiosis gives rise to a linear tetrad. Usually the chalazal macro-spore develops. The embryo sac development is monosporic of the Polygonum type. In a few cases in Dimorphotheca venusta T. Norl. a tetrasporic embryo sac development was observed besides the Polygonum type. Castalis tragus (Ait.) T. Norl. may have a bisporic embryo sac development in addition to the Polygonum type. All the Calendula species develop synergid haustoria. Antipode haustoria occur in Osteospermum sinuatum (DC.) T. Norl. and Chrysanthemoides monilifera (L.) T. Norl. Chalazally situated extra embryo sacs below the ordinary one in Dimorphotheca sinuata DC, D. venusta , and Castalis nudicaulis var. graminifolia (L.) T. Norl. are regarded to be aposporic. Six species have more than three antipodes per embryo sac. The antipodes occasionally become 2-or 4-nucleate.     

Taxonomy of Platyschkuhria (Compositae)

Platyschkuhria is considered to be a monotypic genus of the subtribe Bahianae. Varietal morphologic variation inP. integrifolia is reported.     

The genus Anvillea (Compositae)

The genus Anvillea (Compositae–Inuleae–Inulinae) is found to contain two species which occur in N Africa and the Middle East. Anvilleina Maire is reduced to a synonym of Anvillea and the following two new combinations are made: A. platycarpa (Maire) A. Anderb. and A. garcinii (Burm. f.) DC. ssp. radiata (Coss. & Dur.) A. Anderb. The chromosome number 2n = 14 of A. garcinii ssp. radiata is reported.     

Repetitive DNA in Cichorieae (Compositae)

Thermally denatured DNA of 11 species of Cichorieae (Compositae) was allowed to renature at 69° C in 0.8 M Na⁺. Two distinct fractions of repetitive DNA (fast: 10⁵ repetitions, intermediate: 10³ repetitions) were found in all species. The remaining (slow) fraction comprises 26 to 58% of the genome. The relative amounts of fast and intermediate fractions maintain constant proportions to the slow fraction except for saltatory changes, especially halvings in species with reduced genome sizes.     

Revision ofDoniophyton (Compositae, Barnadesioideae)

This revision describes, illustrates and documents morphological variation inDoniophyton (Compositae, Barnadesioideae), restricted to Argentina and Chile. Two species are recognized,D. anomalum andD. weddellii (sp. nova), possessing distinct morphological and chromosomal features, elevational tolerances, and nearly allopatric distributions.Doniophyton weddellii occurs primarily in central to northern Andean Chile and Argentina from 1900–4000 m a. s. l.;D. anomalum is found principally in centralwestern Argentina and south into Patagonia at 0–1800 m a. s. l. Close relationship exists withChuquiraga of subfam.Barnadesioideae. It is hypothesized thatDoniophyton evolved out ofChuquiraga in the high central Andes between Chile and Argentina. It is suggested thatD. weddellii differentiated first, correlating with an aneuploid chromosomal decrease from n = 27 (inChuquiraga) to n = 25. Further evolution and chromosomal decrease to n = 24 resulted inD. anomalum, with accompanying migration into southern Andes and Patagonia. Nomenclatural changes result from examination of protologues and type specimens:Doniophyton anomalum replaces the commonly used nameD. patagonicum, and a new species,D. weddellii, is described for the taxon masquerading under the routinely used superfluous nameD. andicola. This paper is dedicated with admiration and respect to emer. Univ.-Prof. DrFriedrich Ehrendorfer, one of the world's outstanding plant systematists, and a leading scientist and administrator of the Institute of Botany of the University of Vienna     

Flavonoid races in lasthenia (Compositae)

Nine of the 13 taxa ofLasthenia in which two or more populations were examined for flavonoid constituents exhibited interpopulation variation in these constituents. In certain species entire classes of compounds were present in some races and absent from others. Some of these biochemical differences are due to the failure of certain steps to occur in the biosynthesis of various flavonoids from precursor compounds. Another pattern of variation involves intraspecific differences in the nature of flavonoid glycosides that are produced. In view of the close biosynthetic relationships among all the flavonoids produced byLasthenia, the genetic differences among the flavonoid races of a species may be small. Whether or not these biochemical differences have any adaptive significance is problematical at present.     

Biosystematic study of Berlandiera (Compositae)

Berlandiera is revised to includeB. subacaulis, B. pumila, B. texana, andB. lyrata with its varietieslyrata andmacrophylla. All species may be induced to interbreed readily, producing F₁ progeny which are vigorous but with reduced fertility. Sympatric species produce natural hybrids which are proposed here asB. Xhumilis (=B. pumila XB. subacaulis) andB. Xbetonicifolia (=B. pumila XB. texana). All taxa investigated hadn = 15 chromosomes, including new counts forB. subacaulis and all six F₁ hybrids.     

A functional interpretation ofLactuceae (Compositae) pollen

Pollen morphology and ultrastructure inLactuceae pollen is considered in relation to the accomodation of volume changes, pollination biology and exine-held substances. Echinate pollen grains, such as those ofCatananche, are shown to accomodate volume changes by folding along the colpi and possibly by volume changes in the cavea. The different patterns of echinolophate pollen respond in different ways. Folding along the colpi is important inScorzonera andTragopogon and to a limited extent inCichorium andEpilasia whilst inScolymus the colpi are almost immobilized. Movements of the lacunar floors take over the harmomegathic function to compensate for lack of colpus mobility. Bulging of the intine at the apertures and changes in the size of the cavea may account for part of the volume change accomodated in any pollen type. Echinolophate pollen is interpreted as being a superior means of regulating volume changes with the most economical and mechanically efficient use of wall material which has evolved independently in several tribes ofCompositae.     

Reinstatement of Ocyroe (Compositae: Astereae)

Nardophyllum armatum, a species from the Puna region of Argentina, Bolivia, and Chile is here transferred to genus Ocyroe, which in turn is resurrected from the synonymy under Nardophyllum. Ocyroe is characterized by thorny branches, discoid capitula, naked receptacles, glandular corollas with a globose swelling at the base, and a profuse 3- to 5-seriate pappus. The new combination Ocyroe armata and a lectotype for Dolichogyne armata are here presented.     

鹅不食草中具有抗菌活性的三萜类成分

从鹅不食草(Centipeda minima)全草的乙醇提取物中分离得到3个乌苏烷型三萜,其中一个新化合物用波谱学方法鉴定为ursane-20(30)-en-3β,16β,21α-triol(1),二个已知化合物的结构分别为taraxasterol acetate(2),taraxasterol(3)。抗菌试验表明化合物2和3具有较强的抗菌活性。     

A new Senecio (Compositae) from California

Senecio ganderi is described as new from San Diego County, California. It is referable to theAurei species-group and is distinguished by its orange-yellow corollas, cordate to subcordate basal leaves, and its restriction to chaparral and recently burned areas.     

Flavonoid chemistry of Coreopsis grandiflora (Compositae)

The leaf flavonoid chemistryof Coreopsis grandiflora, which includes var.harveyana, var.longipes, var.saxicola and the typical var.grandiflora, is quite uniform with 6-hy-droxyquercetin 7-O-glucoside, luteolin 7-O-glucoside, marein-maritimein chal-cone-aurone pair and lanceolin-leptosin chalcone-aurone pair as consistent com-ponents. Flavonoid data lend support to the hypothesis that the hexaploid var.longipes originated from parents which would be included withinC. grandiflora, i.e., there is no evidence that other species were involved in its formation. One population of var.grandiflora and several collections of var.saxicola contain additional flavonoid components in the form of flavonol 3-O-glycosides. In nearly all instances the additional compounds are attributable to hybridization withC. lanceolata orC. pubescens because these flavonols are characteristic of these two species and morphological considerations also suggest it. Flavonoid chemistry supports the treatment of var.saxicola as a variety ofC. grandiflora rather than as a distinct species.     

Secondary metabolites from Senecio burtonii (Compositae)

A cacalolide derivative named 4alpha-[2'-hydroxymethylacryloxy]-1beta-hydroxy-14-(5-->6) abeo eremophilan-12,8-olide and a shikimic acid derivative named (3'E)-(1alpha)-3-hydroxymethyl-4beta,5alpha-dimethoxycyclohex-2-enyloctadec-3'-enoate along with three known compounds, octacosan-1-ol, 3beta-hydroxyolean-12-en-28-oic acid and 3beta-acetoxyolean-12-en-28-oic acid were isolated from Senecio burtonii. Their structures and relative configurations were established on the basis of spectroscopic analysis.     

Allozyme variation in Bidens discoidea (Compositae)

Allozyme variation between and within eight populations of the diploid annualBidens discoidea was investigated using gel electrophoresis. The species is relatively homogeneous morphologically in comparison with related species and is highly autogamous. Low levels of within-population variation occur at 16 gene loci, and single alleles are nearly fixed at each of seven loci polymorphic for the species. High levels of differentiation occur between populations, with a mean genetic identity of 0.865. The alleles at the polymorphic loci occur in different combinations in the populations with little apparent geographical pattern. Each population is probably composed of a single lineage of highly homozygous individuals with very limited gene flow between populations.