A. Michael Powell

6-methoxyflavonoids from Brickellia laciniata (Compositae)

Abstract One new and fourteen known flavonoids, including thirteen containing 6-methoxy groups, were isolated from Brickellia laciniata . The new flavonol is quercetagetin 6,4′-dimethyl ether. Among the known compounds identified were the 4′-methyl and 7,4′-dimethyl ethers of eupafolin and luteolin 4′-methyl ether, and the flavonols: patuletin, spinacetin, eupatolitin, eupatin, centaureidin, casticin, patuletin 3-glucoside and 3-galactoside, eupatolitin 3-galactoside, patuletin 3-SO 3 K and eupatin 3-SO 3 Ca 1/2 .

Chromosome numbers in Chihuahuan Desert Cactaceae. III. Trans-Pecos Texas

Chromosome numbers are reported for 112 collections of Cactaceae, including 102 collections of Opuntia. Reports are presented for 33 species in five genera and a total of 36 taxa. Two specimens were sterile. Emphasis was given to the documentation of intraspecific ploidy-level consistencies and differences, because of the current poor state of knowledge about the populational integrity of chromosome numbers in Trans-Pecos cacti and because information about ploidy levels is taxonomically significant particularly in certain genera of Cactaceae. First reports are presented for six taxa, including Opuntia aureispina (2n = 11 II), O. tortispina (2n = 33 II), and Ancistrocactus tobuschii (2n = 11 II). Chromosome numbers are now known for all but one or two of the ∼104 currently recognized cactus taxa in Trans-Pecos Texas.

Marama bean (Tylosema esculentum, Fabaceae) seed crop in Texas

The marama bean, Tylosema esculentum, is a drought- tolerant legume native to southern Africa. Its seeds are comparable to soybeans in protein content and quality, its oil content approaches that of peanuts, and the plants might be desirable as a forage legume. Although the marama bean has great potential as an arid land crop in the United States, studies of the species are extremely limited. The current investigations have demonstrated that the plants can be grown successfully in an arid region of the United States, at least under experimental conditions, and that a healthy seed crop can be expected in about 4.5 years.

Taxonomy of tridax (Compositae)

Tridax is a Mexican, Central American, and South American genus with its greatest concentration of species in Mexico. One weedy species, T. procumbens, has been widely introduced in the tropical and subtropical regions of the world. This genus is a member of the tribe Heliantheae, subtribe Galinsoginae. Hoffmann (1894), De Candolle (1836), Bentham (1873, p. 446), and Bcntham and Hooker (1876) have included Galinsoga, Calea, Balduina, Marshallia, Blepharipappus, Dubautia, Raillardia, and Bebbia (the latter 2 only by Hoffmann) with Tridax in Galinsoginae. A modern conspectus of Galinsoginae would exclude some of the genera placed in that subtribe by earlier workers. Carlquist (1959) excludes, on the basis of anatomical evidence, Blepharipappus, Dubautia, and Raillardia, assigning them to the subtribe Madinae. Rock (1957) and Turner et al. (1961) point out a closer relationship of Balduina (including Actinospermum) to genera now included in the tribe Helenieae. Cronquist (1955, p. 496) notes that Marshallia is probably anomolous in Galinsoginae, and suggests a closer relationship with Vernonieae or Eupatorieae. Of the remaining genera, Galinsoga is probably most closely related to Tridax. Species of Tridax having a pappus of ciliate or fimbriate scales and glabrous or puberulent achenes have been confused with Galinsoga. However, Galinsoga can be readily distinguished from Tridax by several features, briefly enumerated as follows:

Experimental documentation of natural hybridization inCactaceae: Origin of Lloyd's Hedgehog Cactus,Echinocereus ×lloydii

The origin ofEchinocereus ×lloydiiBritt. & Rose, pro sp. (Lloyds Hedgehog Cactus) was investigated using comparative morphology, cytology, biochemistry, and particularly, artificial hybridization. Numerous artificial crosses between the putative parentsE. coccineusEngelm. (a species of claret-up cactus) andE. dasyacanthusEngelm. (Texas Rainbow Cactus) were successful, resulting in the production of hundreds of seeds with hybrid embryos. The F1 hybrid progeny (i.e., syntheticE. ×lloydii) grew to sexual maturity in about four and one-half years, whereupon successful backcrosses and F2 generation hybrids were also obtained. The known F1 hybrids closely approximated naturalE. ×lloydii. The fertility of these syntheticE. ×lloydii was high, like their natural counterparts. The populations ofE. ×lloydii in Pecos County, Texas are inferred to have originated as the result of natural interspecific hybridization. It is assumed thatE. ×lloydii or similar plants may arise wherever the parental taxa grow sympatrically.

Sesquiterpene lactones from Perityle vaseyi

Abstract The well-known germacrolide, eupatoriopicrin, and two additional sesquiterpene lactones, were isolated from Perityle vaseyi . The latter two lactones, one a novel guaianolide and the other a known germacrolide, both contain unusual ten carbon diester side chains attached at C-8. The chemical evidence, in conjunction with morphological data, suggest that Perityle, and hence the subtribe Peritylinae, should be placed in the tribe Heliantheae.

Second generation experimental hybridizations in theEchinocereus ×lloydii complex (Cactaceae), and further documentation of dioecy inE. coccineus

Artificial second generation and backcross hybrids involvingEchinocereus dasyacanthus (Texas rainbow cactus),E. coccineus (a species of claret-cup cactus), andE. ×lloydii (Lloyds hedgehog cactus) were examined for morphological and reproductive characteristics. The hybrids grew from seed to flower in about four years, and they exhibited high fertility as measured by pollen stainability, crossability, and fruit-set. A rare breeding system inCactaceae, dioecy, was further examined inE. coccineus, using field and controlled pollination tests. Functional dioecy was documented forE. coccineus in Trans-Pecos Texas. All results suggested thatE. ×lloydii in eastern Pecos County, Texas, is a complex and dynamic population probably comprising first and later generation hybrids, including backcross hybrids. The experimental hybridizations also tended to support the occurrence of introgression into both putative parental species.

Systematic implications of the flavonoids and chromosomes ofFlyriella (Compositae—Eupatorieae)

The leaves of five species ofFlyriella were found to contain from one to four glycosides of quercetin and its 4′- and 7,4′-methyl ethers. These patterns are distinct from those observed for more than seventy species ofBrickellia and support morphological and chromosomal data which indicate thatFlyriella should not be treated as an element ofBrickellia. Alternative treatments are briefly considered.

Natural intersectional hybridization in perityle (Compositae)

A small number of supposed F1 hybrids was discovered in an isolated sympatric population ofP. parryi (n = 17) andP. rupestris var.albiflora (n = 17) in the Chisos Mts. of Texas. Although the parental species are morphologically quite distinct, being assigned to separate taxonomic sections ofPerityle, their hybrids displayed relatively high fertility. Origin of the presumed natural hybrids was documented by the production of artificial hybrids betweenP. parryi andP. rupestris var.albiflora. Fertility data based on pollen stainability were accumulated for the available natural hybrids, and for artificial hybrids through F3 and backcross generations. A brief discussion of biosystematic implications is included.

Correllia (Compositae: Peritylinae) : A new monotypic genus from southern Chihuahua, Mexico

A new genus,Correllia, and its single species,C. montana, are described from Sierra Mohinora in southwestern Chihuahua, Mexico. The genus belongs in subtribe Peritylinae (Compositae tribe Helenieae) and appears to be most closely related toPerityle.