INTRODUCTION 



An investigation to determine chromosome numbers for populations of 

 Cirslum longlstylum, populations of putative hybrids and of a reference 

 population of Cirsium hookerianum was undertaken as per MT HER Contract Number 

 0607090. Field collection of meiotic material was undertaken on 1 July 1990 

 and 6-8 July 1990. Seed was collected from one locality on 3 September 1990. 

 Labwork was conducted in July and September. 



METHODS 



Determination of species identity followed Hitchcock et al 1959 and Dorn 

 1988. Many populations collected had been previously diagnosed. Meiotic 

 material from five to ten individuals per population was collected and fixed 

 in the field in Farmer's solution (3:1, 95% ethanoliglacial acetic acid). 

 Buds were transferred after 24 hours to 70% ethanol. Anthers dissected from 

 preserved buds were squashed in 45% aceto-orcein for examination under phase- 

 contrast microscopy. Mitotic material was obtained from germinated seed of 

 one population. Root tips for mitotic squashes were pretreated in 8- 

 hydroxyquinoline for 4 hours. Root tips were then placed in orcein-Hcl (9:1) 

 and gently heated several times. After hydrolysis, root tips were squashed in 

 45% aceto-orcein for examination under phase-contrast microscopy. 



RESlHiTS 



Counts were obtained from six of the thirteen Cirsium longistylum 

 designated in the contract. Both seed and meiotic material was collected from 

 a reference population of Cirsium hookerianum in the Roger's Pass vicinity, 

 but a count was not obtained. Table 1 presents counts obtained by the author, 

 as well as counts from the literature of species thought to be involved in 

 hybridization with Cirsium longistylum. Citations of all populations 

 collected are found in the appendix. 



