CHROMOSOME NUMBERS IN COMPOSITAE. VI. SENECIONEAE. II

Chromosome counts are reported for 76 taxa and 2 natural hybrids of tribe Senecioneae (Compositae). First counts are reported for several species of Senecioneae as well as for the genera Cadiscus and Whitneya. New chromosome numbers are added to those previously known in Arnica, Cacalia, and Senecio. Additional counts from Arnica support our previous suggestion that x = 19 for this genus. It is assumed that observed meiotic irregularities are associated with apomixis in this genus. Basic chromosome numbers for various New World sections of Senecio are proposed, and certain problems of sectional relationships in this genus are discussed. Chromosome numbers and plant morphology of Cadiscus, Hulsea, and Whitneya indicate that these genera should be removed from Helenieae to Senecioneae. The possible affinity of the anomalous genus Adenocaulon with Mutisieae is discussed. Data presented in the paper further support our earlier proposal that the basic chromosome number for Senecioneae is x = 10.     

CHROMOSOME NUMBERS IN COMPOSITAE. I. ASTEREAE

Raven , Peter H. (U. California, Los Angeles.), Otto T. Solbrig , Donald W. Kyhos , and Richard Snow . Chromosome numbers in Compositae. I. Astereae. Amer. Jour. Bot. 47(2) : 124—132. Illus. 1960.–Ninety-two new counts are reported for the tribe Astereae of Compositae, mostly based on determinations of meiotic material. These include the first counts reported for the genera Acamptopappus, Amphipappus, Benitoa, Chrysothamnus, Corethrogyne, Lessingia, Monoptilon, and Xanthocephalum, as well as for many species. The original counts are discussed in relation to those previously reported for the tribe; together these constitute a total of 39 genera examined cytologically out of the approximately 100 known. Because of its widespread occurrence in diverse phylogenetic lines within the tribe and the family, and because of its high degree of correlation with the woody habit, which is thought to be primitive, x=9 is regarded as the original basic number for Astereae. Within the Haplopappus alliance there is a strong secondary mode of chromosome numbers centering around x=5. The hiatus between these two modes in number is explained on the basis of ancient phylogenetic reduction in chromosome number followed by the extinction of less successful intermediate types, and is compared with similar trends that have been reported for Cichorieae. It is suggested that the family is not of polyploid origin but may have had an original diploid basic number.     

CHROMOSOME NUMBERS IN THE COMPOSITAE. XIV. LACTUCEAE

Reports of 150 original chromosome counts are recorded, including reports of 22 genera and 57 species and subspecific taxa in tribe Lactuceae. Also included are first reports for 12 specific or subspecific taxa. x = 9 appears to be the ancestral base of the tribe. Chromosome numbers are known for over 85% of the genera of the tribe and the frequency of polyploidy is ca. 23%, which is about one-half that of the angiosperms.     

CHROMOSOME NUMBERS IN COMPOSITAE VIII: HELIANTHEAE

One hundred and ninety-three new counts are reported for the tribe Heliantheae of Compositae, mostly based on determinations of meiotic material, including first counts for the genera Adenothamnus, Chrysogonum, Enceliopsis, Guardiola, Isocarpha, Lipochaeta, Otopappus, and Oyedaea, as well as first counts for 66 species. The original counts are discussed in relation to those previously reported for the tribe, by genera and subtribe. Two-thirds of the approximately 150 genera and more than a third of the roughly 1500 species have now been examined. The incomplete knowledge of generic relationships in the tribe often make the interpretation of these chromosome numbers difficult. Three observations are documented and discussed: (1) genera with low chromosome numbers are few; (2) genera with aneuploid series are abundant; and (3) the original basic chromosome number in the tribe is probably in the range of x = 8 to x = 12.     

(Un)Targeted Metabolomics in Asteraceae: Probing the Applicability of Essential‐Oil Profiles of Senecio L. (Senecioneae) Taxa in Chemotaxonomy

The possible applicability of (un)targeted metabolomics (volatile metabolites) for revealing taxonomic/evolutionary relationships among Senecio L. species (Asteraceae; tribe Senecioneae) was explored. Essential‐oil compositional data of selected Senecio/Senecioneae/Asteraceae taxa (93 samples in total) were mutually compared by means of multivariate statistical analysis (MVA), i.e., agglomerative hierarchical clustering and principal component analysis. The MVA input data set included the very first compositional data on the essential oil extracted from the aerial parts of S. viscosus L. as well as on four different Serbian populations of S. vernalis Waldst . & Kit . (oils from aerial parts and roots; eight samples in total). This metabolomic screening of Senecio/Senecioneae/Asteraceae species (herein presented results and data from the literature) pointed to short‐chain alk‐1‐enes (e.g., oct‐1‐ene, non‐1‐ene, and undec‐1‐ene), with up to now restricted general occurrence in Plantae, as characteristic chemotaxonomic markers/targets for future metabolomic studies of Senecio/Senecioneae taxa. The MVA additionally showed that the evolution of the terpene metabolism (volatile mono‐ and sesquiterpenoids) within the Asteraceae tribe Senecioneae was not genera specific. However, the MVA did confirm plant‐organ specific production/accumulation of volatiles within S. vernalis and suggested the existence of at least two volatile chemotypes for this species.     

CHROMOSOME NUMBERS IN COMPOSITAE. II. HELENIEAE

Raven , Peter H. (Rancho Santa Ana Botanic Garden, Claremont, Calif.), and Donald W. Kyhos. Chromosome numbers in Compositae. II. Heleniae. Amer. Jour. Bot. 48(9): 842–850. Illus. 1961.—Chromosome counts are now available for 42 of the approximately 55 genera of Compositae, tribe Helenieae, which is predominantly a group of western North America. These chromosome numbers are summarized here at the generic level, and 100 original counts for the tribe are added, including what seem to be the first published reports for the genera Amblyopappus, Baeriopsis, Hulsea, Jaumea, Pericome, Rigiopappus, Trichoptilium, and Venegasia, as well as for many species. The phylogeny of Chaenactis is discussed in the light of published records and 46 original counts, and C. douglasii is shown to include plants in which n = 6, 12, and 18, which differ somewhat morphologically. Helenium has species which have a complete series of aneuploid numbers from n = 13 to n = 17. Chromosome numbers coincide with morphological variability in indicating that Helenieae are a diverse group. More detailed studies of various kinds will be necessary before the genera of Helenieae can be re-aligned effectively, but it is evident that different genera show affinities with various other tribes of the family. Nevertheless, it is thought to be convenient to continue to recognize Helenieae at the tribal level for the present.     

The origin of Dendrosenecio within the Senecioneae (Asteraceae) based on chloroplastDNA EVIDENCE

Chloroplast DNA restriction-site variation was surveyed using 15 enzymes for 37 accessions from the tribe Senecioneae (Asteraceae), plus two outgroup species, in order to determine the placement within the tribe of the giant senecios (Den-drosenecio). The survey revealed 176 phylogenetically informative mutations and 121 autapomorphic mutations. Dendro-senecio is diagnosed by a minimum of 15 mutations, which suggests that the giant senecios evolved from a relatively isolated lineage within the Senecioneae, and this conclusion is supported by earlier evidence from chromosome counts and phytochemistry. Among the taxa sampled, the closest relatives of Dendrosenecio are Cineraria deltoidea and two species of Euryops. Support was not found for suggestions in the literature that the closest relatives of Dendrosenecio are species in Solanecio or Senecio subgen. 'Crociseris.' The position of the Dendrosenecio/Cineraria/Euryops clade is weakly supported as basal to the majority of other senecionoid genera. The tussilaginoid genera sampled (Ligularia, Petasites, Roldana, and Tussilago) are monophyletic in our analysis, with the surprising inclusion of Pericallis hybrida as the sister-taxon to Roldana suffulta. The sister-group to the Dendrosenecio/Cineraria/Euryops clade includes all species of Delairea, Gynura, Kleinia, Packera, Senecio, and Solanecio sampled. Within Senecio, subgenera Senecio and ‘Crociseris’ form a monophyletic core, with subgenus ‘Kleinioidei’ being broadly paraphyletic or possibly polyphyletic.     

CHROMOSOME NUMBERS IN UMBELLIFERAE. IV.

Chromosome numbers are reported for 167 collections representing 100 taxa of Umbelliferae. More than four-fifths of the counts apply to members of subfamilies Hydrocotyloideae (29) and. Saniculoideae (50); the remaining 21 belong to Apioideae. Chromosome numbers of plants belonging to 68 taxa are published here for the first time; chromosome numbers are verified for 23 taxa; and chromosome numbers differing from those published previously are reported in nine instances. No chromosome counts have previously been reported for 19 of the genera included. Polyploidy has been established for Azorella, Mulinum, Coaxana, Enantiophylla, and Tiozimia.     

Chromosome numbers of miscellaneous Malagasy Acanthaceae

Meiotic chromosome numbers are reported for 12 species in eight genera of Acanthaceae from Madagascar. Chromosome numbers of 11 species are reported for the first time. Counts inMendoncia (n=19) andNeuracanthus (n=20) are the first for these genera. A new chromosome number (n=30) is reported inJusticia. Systematic implications of the chromosome counts are addressed and basic chromosome numbers for these eight genera of Malagasy Acanthaceae are discussed.     

CHROMOSOME NUMBERS IN UMBELLIFERAE. III

Chromosome numbers are reported for 156 collections representing 100 taxa of Umbelliferae. Approximately two thirds of the collections are from Mexico, Central and South America and indicate a high percentage of polyploid species in certain genera found in this area. Chromosome numbers for plants belonging to 78 taxa are published here for the first time, previously published chromosome numbers are verified for 18 taxa and chromosome numbers differing from those previously published are reported in seven instances. No chromosome counts have been previously published for nine of the genera included here. Further aneuploidy and polyploidy were found in Eryngium, and Lomatium columbianum has been found to be a high polyploid with 2n = 14x. Every chromosome count is referable to a cited herbarium specimen.     

CHROMOSOME NUMBERS IN COMPOSITAE V. ASTEREAE II.

Reports of 100 new chromosome counts are made for the tribe Astereae of Compositae, mostly based on determinations of meiotic material, including first counts for 9 genera and 53 species. Counts are now available for 58 of the approximately 100–120 genera and 431 of the approximately 2000 species in the tribe. Comparisons are made between chromosome number and habit and also between chromosome number and geographical distribution. Species and genera with a basic number of x = 9 are the most abundant. Within different phyletic lines x = 9 is also the most abundant number. On the other hand, many species with x = 4 and 5, belonging to a number of small, largely annual genera, are concentrated in southwestern North America. The low chromosome number in these plants is probably correlated with the dry habitat they occupy, and is most likely a specialized condition.     

New chromosome counts and evidence of polyploidy in Haageocereus and related genera in tribe Trichocereeae and other tribes of Cactaceae

Chromosome numbers for a total of 54 individuals representing 13 genera and 40 species of Cactaceae, mostly in tribe Trichocereeae, are reported. Five additional taxa examined belong to subfamily Opuntioideae and other tribes of Cactoideae (Browningieae, Pachycereeae, Notocacteae, and Cereeae). Among Trichocereeae, counts for 35 taxa in eight genera are reported, with half of these (17 species) for the genus Haageocereus. These are the first chromosome numbers reported for 36 of the 40 taxa examined, as well as the first counts for the genus Haageocereus. Both diploid and polyploid counts were obtained. Twenty nine species were diploid with 2n=2x=22. Polyploid counts were obtained from the genera Espostoa, Cleistocactus, Haageocereus, and Weberbauerocereus; we detected one triploid (2n=3x=33), nine tetraploids (2n=4x=44), one hexaploid (2n=6x=66), and three octoploids (2n=8x=88). In two cases, different counts were recorded for different individuals of the same species (Espostoa lanata, with 2n=22, 44, and 66; and Weberbauerocereus rauhii, with 2n=44 and 88). These are the first reported polyploid counts for Haageocereus, Cleistocactus, and Espostoa. Our counts support the hypothesis that polyploidy and hybridization have played prominent roles in the evolution of Haageocereus, Weberbauerocereus, and other Trichocereeae.     

CHROMOSOME NUMBERS IN THE PHASEOLEAE (FABACEAE:FABOIDEAE) AND THEIR RELATION TO TAXONOMY

Chromosome numbers are reported for 33 species of the tribe Phaseoleae. Six reports are first counts for their species; one report (Ophrestia hedysaroides) is a first count for the genus. This increases the number of genera counted to 53 out of a total 84 for the tribe. A survey of base numbers shows a general pattern of numbers 10 or 11, the same base numbers as in the neighboring tribes Dalbergieae sensu lato, Galegeae sensu lato, and Abreae. The chromosomes are generally small and polyploidy is uncommon. Deviations from base numbers 10 or 11 are mostly found in those genera with morphological pecularities and puzzling taxonomic placements: Erythrina (21), Clitoria (8, 11, 12), Butea (9), Calopogonium (18), Teramnus (14), and Strongylodon (14). Two genera have base numbers which suggest derivation by polyploidy: Glycine (20) and Cologania (22).     

CHROMOSOME NUMBERS IN UMBELLIFERAE. II

Bell , C. Ritchie (U. of North Carolina, Chapel Hill.), and Lincoln Constance . Chromosome Numbers in Umbelliferae. II. Amer. Jour. Bot. 47(1) : 24-32. Illus. 1960.–Chromosome numbers are reported for plants representing an additional 100 taxa of Umbelliferae. Chromosome numbers for 77 of these taxa are published here for the first time, previously published chromosome numbers of 19 taxa are verified, and numbers differing from those previously published are reported in 4 instances. Ten of the genera included here have been previously unknown cytologically. Polyploidy has been discovered in Bowlesia and confirmed in Pimpinella. Aneuploid series appear to occur in Eremocharis, Eryngium, Oenanthe, Perideridia, and Ptilimnium. Every chromosome count is referable to a cited herbarium specimen.     

Cytotaxonomy of Senecio tricuspis (Asteraceae–Senecioneae)

The chromosome number of 2n=40 counted for Senecio tricuspis (Asteraceae–Senecioneae) indicates that the species should not be transferred to the genus Parasenecio but be retained in Senecio.     

CHROMOSOME NUMBERS AND THEIR SYSTEMATIC IMPLICATIONS IN HAWAIIAN LOBELIOIDEAE (CAMPANULACEAE)

Chromosome numbers are reported for 20 collections of Hawaiian Lobelioideae (Campanulaceae), representing six genera, 13 species, and two interspecific hybrids. All are n = 14. Chromosome numbers are reported for the first time for eight species of Clermontia, Cyanea, Delissea, Lobelia, and Trematolobelia; the report for Delissea is the first for that genus. Additional determinations confirmed previously reported numbers in five other species of Brighamia, Clermontia, and Cyanea. Chromosome numbers are now known for all seven genera and 20 of the 110 species. All accepted counts are n = 14. It is suggested that all Hawaiian Lobelioideae share this number and are paleotetraploid. There is no evidence that the prolific speciation evident among these plants was accompanied by euploid or aneuploid change in chromosome number. The Hawaiian Lobelioideae, particularly the monophyletic lineage of 91 baccate species, offer further support for the generalization that change in chromosome number is an uncommon mode of speciation in insular floras.     

CHROMOSOME COUNTS OF COMPOSITAE FROM THE UNITED STATES AND MEXICO

Chromosome counts are reported for 126 taxa representing 122 species and 61 genera of Compositae. First reports include two genera, Stylocline (n = 14) and Chromolepis (n = 19), 17 species, two infraspecific taxa, and one interspecific hybrid. Five additional taxa have chromosome numbers differing from previously published accounts. Carminatia is reinstated to generic status.     

CHROMOSOME NUMBERS IN COMPOSITAE. IX. HAPLOPAPPUS AND OTHER ASTEREAE

Reports of 209 original chromosome counts are made for the tribe Astereae of Compositae, including first counts for two genera and 46 species or subspecies. With over 80 % of the species counted, chromosome numbers are now available for all North American sections of Haplopappus. Two major groupings are apparent: one, with basic numbers of x = 4, 5, or 6, is basically herbaceous; the other, with x = 9, consists of shrubs or subshrubs. Aneuploidy is known only in the “herbaceous” group of Haplopappus, and polyploidy is more extensive there than in the woodier group of sections.     

Karyological features and cytotaxonomy of the tribe Vernonieae (Asteraceae)

Chromosome numbers are reported for 29 populations of 19 Vernonieae taxa collected mainly in the northeastern region of Brazil. Among them, data for five genera (Blanchetia, Rolandra, Pithecoseris, Stilpnopappus and Vanillosmopsis) are here reported for the first time, and the first chromosome counts are presented for 12 species. Chromosome numbers are quite diverse among and sometimes within genera, especially in the controversial and large subtribe Vernoniinae. The numbers varied from 2n = 18 to 2n = ~72. The main karyoevolutionary mechanism seems to be dysploidy, while polyploidy is probably associated with ancient hybridization processes generating most paleotetraploid genera. All studied species presented semi-reticulated interphase nuclei and proximal-early condensing behavior in prophase to prometaphase. In one species (Vernonia condensata with 2n = 40) fluorochrome staining with CMA/DAPI revealed five chromosome pairs bearing subterminal CMA⁺/DAPI^? heterochromatin, probably NOR-associated, revealing the existence of low amounts of satellite DNA. The role of these features in the evolution of the tribe is discussed, revealing some interesting aspects for understanding of the Vernonieae karyoevolution, especially regarding neotropical members.     

CHROMOSOME COUNTS AND TAXONOMIC NOTES FOR COMPOSITAE FROM THE UNITED STATES AND MEXICO

Chromosome counts are reported for 167 taxa representing 160 species and 76 genera of Compositae. First reports for 27 species and 2 infraspecific taxa are included. New chromosome numbers are reported for 9 additional taxa. The genus Carminatia DC. is merged with Brickellia Ell. resulting in two new combinations: Brickellia tenuiflora (DC.) Keil & Pinkava and Brickellia recondita (McVaugh) Keil & Pinkava.