CHROMOSOME CYTOLOGY OF EUCHARIS, CALIPHRURIA, AND URCEOLINA (AMARYLLIDACEAE)

Karyotypes are presented for 19 taxa of Eucharis, Caliphruria, and Urceolina, a monophyletic group of Andean Amaryllidaceae within "infrafamily" Pancratioidinae Traub. All three genera are characterized by 2n = 46, the most common somatic number occurring in the "infrafamily." Incidences of polyploidy are low. Only two tetraploid (2n = 92) species of Eucharis are so far known, E. bouchei and E. bonplandii, the northernmost species of E. subg. Eucharis. The 2n = 68 karyotype of E. amazonica is interpreted as triploid-derived (3x 1). Chromosomal heteromorphism is reported for C. subedentata. Karyotype data is analyzed with principal component analysis and unweighted pairgroup cluster analysis. In a number of cases, phenetic relationships among the karyotypes correlate with phenetic and cladistic relationships based on morphological data. Karyotype evolution among the three genera is discussed in the context of classical theories of karyotypic symmetry. Stability of chromosome number in Eucharis and related genera suggests that chromosomal evolution has proceeded via nonreciprocal interchanges between chromosomes and infrachromosomal structural change. In at least one case (E. bakeriana), rapid sympatric speciation may have been vectored by chromosomal change. EUCHARIS PLANCHON & LINDEN, Caliphruria Herbert and Urceolina Reichenbach form a monophyletic group of neotropical Amaryllidaceae (Traub, 1963; Meerow, 1986), ecologically specialized to the understory of primary, rarely secondary, tropical rain forest below 2,000 m elevation. All three genera have petiolate leaves, and occur in edaphic situations of high fertility (Meerow, 1986). The genera separate on the basis of perianth, staminal, pollen, stigma, and seed morphology. As a group they represent a distinct tribal assemblage within "infrafamily" Pancratioidinae Traub (1957, 1963), a subfamily delimited by various patterns of staminal connation, a frequent somatic chromosome number of 2n = 46, and an Andean center of diversity (Meerow, 1985, 1986, 1987). The species are rare in nature, endemism is high, and several species in each genus are undoubtedly close to extinction. Eucharis is the largest and most widely ' Received for publication 22 September 1986; revision accepted 3 February 1987. I thank the many contributors of living material of these genera, too numerous to mention individually. Bijan Dehgan provided the supportive atmosphere where this work was accomplished. Walter S. Flory and Tasneem F. Khaleel provided useful reviews of an earlier version of this paper. Portions of this work were supported by NSF Doctoral Dissertation Improvement Grant BSR-8401208, and a Garden Club of America/World Wildlife Fund Fellowship in Tropical Botany. This paper represents portions of a doctoral dissertation submitted to the graduate school of the University of Florida. Florida Agricultural Experiment Station Journal Series No. 7601. distributed of the three genera, found from Guatemala to Bolivia. The center of diversity for the genus is in western Amazonas and the adjacent eastern Andes. In a recent monograph (Meerow, 1986), sixteen species in two subgenera are recognized. Caliphruria consists of four species, three of which are endemic to Colombia (Meerow, 1986). Urceolina (ca. 6-8 species) is so far known only from central and southern Peru, on the eastern Andean slopes. Traub (1971) combined all three genera into Urceolina without any supporting data, a taxonomic decision few workers have followed. Chromosome cytology ofAmaryllidaceae has been a favored subject for investigation, chiefly due to the large size of the chromosomes and availability of material (Sharma and Bal, 1956). The subject has been reviewed by Flory (1977) and Meerow (1984a). Mitotic studies have dominated the literature. Microsporogenesis occurs completely inside the bulb when the inflorescence is nascent, and numerous bulbs must therefore be sacrificed for meiotic analysis without guarantee that necessary stages will be obtained (Ponnamma, 1978; Nagalla, 1979; Williams, 1981). Nonetheless, chromosome cytology of only a few species of Eucharis has been reported in the literature: E. amazonica Linden ex Planchon (Sato, 1938; Mookerjea, 1955; Nagalla, 1979), and E. plicata Meerow (1984b; incorrectly as 2n = 44). No accurate reports on Caliphruria and Urceolina have, to my knowledge, appeared. A large living collection of these