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Chromosome numbers are reported for 111 collections of Umbelliferae, which represent 38 species belonging to 23 genera. Three of these genera, Aletes, Neoparrya, and Musineon, have not been counted previously. In addition, first counts are presented for Angelica grayi, A. roseana, Cymopterus acaulis, C. bulbosus, C. longipes, C. inontanus, Lomatium foeniculaceum subsp. macdougalii, L. megarrhizum, L. nuttallii, L. orientale, and L. simplex. Our reports of polyploidy in Ligusticum porteri (hexaploid, 2n = ca. 66) and in Pteryxia terebinthina var. calcarea (tetraploid, 2n = 44) are the first for these taxa. The counts of 2n = 22 for Harbouria trachypleura differ from the previous report of 2n = 20. OUR KNOWLEDGE of chromosome numbers in the Umbelliferae has been enhanced greatly by the three publications of Bell and Constance (1957, 1960, 1966) and the recent paper of Constance, Chuang, and Bell (1971). With the exception of the pioneering work of these authors, no concentrated efforts have been directed toward gathering chromosomal information on Umbelliferae. The present study, which concerns chromosome numbers in Rocky Mountain Umbelliferae, had three primary objectives: (1) to provide cytological information for those species which were previously unknown chromosomally; (2) to gather data for those taxa which had not been counted from the Rocky Mountains, even though there might be records from other parts of their ranges; (3) to provide additional chromosomal information for those species for which there are only one or a few records. MATERIALS AND METHODS-Floral buds were fixed in a modified Carnoy's solution of chloroform: absolute ethanol: glacial acetic acid (4: 3: 1 ). After 24-48 hr the material was transferred to 70 % ethanol and stored in a refrigerator. The anthers were squashed in acetocarmine, and the chromosomes were counted in the dividing microsporocytes. Camera lucida drawings were made from cells of most preparations, but only those which are new records or differ from previous reports are illustrated. Collection numbers 36-363 are those of Crawford; 2954-3187 refer to those of Hartman. All voucher specimens are deposited in the Rocky Mountain Herbarium (RM). 1Received for publication 11 October 1971. Supported by a grant from the College of Arts and Sciences, Division of Basic Research, University of Wyoming. We express our appreciation to Dr. Lincoln Constance for reading the manuscript. 2 Present address: Department of Botany, University of Texas, Austin. RESULTS AND DISCUSSION-Only those counts which represent first reports for a species, which differ from any previous determination, or which appear to be of particular taxonomic interest will be included in the discussion. Collection numbers which are in italics in Table 1 are those for which chromosomes have been illustrated. Aletes-This genus was revised by Theobald, Tseng, and Mathias (1964), but nothing has been known concerning its cytology. We have obtained counts for three of the five species recognized by these authors. All prove to be uniformly diploid with a number of 2n = 22 (Fig. 1-3). Of particular interest is A. humilis, which is apparently endemic to the area around Dale Creek, near the Colorado-Wyoming border. Few collections are known, the last made nearly 60 years ago. We experienced little difficulty in finding the species at this locality, where it is quite abundant. Angelica-Two species, A. grayi and A. roseana, are reported here for the first time. Both are diploid (2n = 22), and the base number of x = 11 is in agreement with all previous reports for the genus (Fig. 4, 5). Berula-Two collections of B. erecta from rather widely separated localities were studied. Interestingly, our determinations of 2n = 18 for both of these gatherings differ from the only previously reported count from North America (Fig. 6). Bell and Constance (1957) listed a collection from Illinois as 2n = 12. There is a report the same as ours in the Russian literature. Certainly additional sampling is needed for this species to determine whether or not these different counts can be correlated with geographic distribution or other factors. Cicuta-Two ploidy levels have been reported for C. douglasii. Bell and Constance (1957) de |
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