Cytological Observations on Certain Compositae

Abstract

After an examination of the literature on chromosome counts had revealed the fact that in most instances the chromosome numbers of latesummer-flowering angiosperms are unknown. this study was undertaken. During August and September, 1933, numerous species were collected and prepared for examination. The following Compositae were among those examined:Ageratum Houstonianum Mill., Eupatorium pur pureum L., E. urticaefolium Reichard, Erigeron canadensis L., Ambrosia trifida L., A. artemisiifolia L., Heliopsis helianthoides (L.) Sweet, Helianthus grosseserratus Martens, Gaillardia aristata Pursh, Chrysanthemum Leucanthemum L. var. pinnatifidum Lecoq. and Lamotte, Sonchus oleraceus L., and Lactuca scariola L. var. integrata Gren. and Godr. MATERIAL AND METHODSMaterial was fixed in Carnoy's fluid (6 parts 9S per cent alcohol, 2 parts chloroform, 2 parts glacial acetic acid). The young buds were left in this fixative about one hour, washed in 9S per cent alcohol, and imbedded in paraffin after clearing with cedar oil.Sections were cut from I2-IS II. in thickness, mounted serially, and stained in Delafield's haematoxylin. The stain was diluted, using I part of stain to 3 parts ordinary tap water, and the sections were allowed to remain in this solution from one to two hours. They were washed in running water for 20 minutes and then transferred to acid alcohol (one drop of hydrochloric acid to two hundred cc. of 70 per cent alcohol) to remove the excess stain. The material was examined under the microscope in order to determine the amount of stain in the tissue. When properly destained, they were placed in ammonia alcohol for a short time, dehydrated, and mounted in Canada balsam in the usual manner. OBSERVATIONSThe chromosome counts herein reported were made in part from nuclei in diakinesis, and in part from polar views of heterotypic or homoeotypic equatorial plates in the microspore mother cells.

Cytomorphological Diversity in Some Members of Family Asteraceae from the Ecologically Disturbed Habitats of Solang Valley, Kullu District, Himachal Pradesh

“…2i). The 4x cytotype with similar type of meiotic behavior has also been reported by different workers from India (Mehra et al 1965, Kumar 1982, Gupta and Gill 1984a, 1989) and outside of India (Tahara 1915, 1921, Tischler 1934, Cooper and Mahony 1935, Negodi 1937, Rohweder 1937, Löve and Löve 1956, Gadella and Kliphuis 1963, 1966, Engelskjon 1979, Van Loon and Kieft 1980. The species is also known to have diploid cytotype with 2n=18 (Gadella and Kliphuis 1963, Mehra et al 1965, Taylor and Mulligan 1968, Engelskjon 1979, Kumar 1982, Gupta and Gill 1984a, 1989 6x, 2n=54 (Dowrick 1952, Böcher and Larsen 1957, Mulligan 1958) and 8x, 2n=72 (Favarger 1963) cytotypes.…”

Effect of nitrogen and phosphorus on flowering and yield of gaillardia (Gaillardia pulchella Foug.) CV. Local yellow under Jhalawar condition

“…The generic name Gaillardia was proposed by Mr. Gaillard de Marentoneau, the French botanist 18th century. Gaillardia pulchella is diploid (2n=36) as reported by Morinaaga et al (1929) [13] and Gaillardia aristata is diploid (Cooper and Mahony, 1936) [3] and tetraploid, 2n = 78 (Atwood, 1937) [1] . Besides its utility in landscape and as cut flowers, Gaillardia is useful in reducing erosion in coastal dune areas (Carig, 1977) [2] .…”

Chromosome Studies in Liatris. I. Spicatae and Pycnostachyae

“…As two were smaller than the others he considered them to be unpaired chromosomes of a geminus and though noting them lag-ging on the heterotypic spindle, never found any irregularity in the tetrads. Cooper and Mahony (1935) reported for Gaillardia aristata of the Helenieae one or more pairs of lagging chromosomes on both first division anaphase and after the completion of second division. Supernumerary nuclei resulted in abnormal two-nucleate microspores or abortive micro pollen grains.…”