CHROMOSOME NUMBERS OF CAMPANULACEAE. III. REVIEW AND INTEGRATION OF DATA FOR SUBFAMILY LOBELIOIDEAE

Chromosome numbers are now known for 153 species in 21 genera of Lobelioideae (Campanulaceae); this represents almost 13% of the species and 70% of the genera in the subfamily. Numbers reported are n = 6, 7, 8, 9, 10, 11, 12, 13, 14, 19, 21, 35, 70. The subfamily as a whole has x = 7; the best documented exception is Downingia and its allies with x = 11. Only four genera show interspecific variation in chromosome number: Downingia (n = 6, 8, 9, 10, 11, 12); Lobelia (n = 6, 7, 9, 12, 13, 14, 19, 21); Pralia (n = 6, 7, 13, 14, 21, 35, 70); and Solenopsis (n = 11, 14). Intraspecific variation occurs in 13 species, with as many as four different cytotypes in one species. The herbaceous members of the subfamily as a group are quite variable, showing the entire range of chromosome numbers, including numerous dysploids, but are predominantly diploid. The woody species, by contrast, are much less variable; nearly all of the species are tetraploid, with only a few diploids and hexaploids and no dysploid numbers known. These data support the hypothesis that woodiness is apomorphic within the subfamily. A general trend of higher chromosome numbers at higher latitudes and higher elevations is evident within the subfamily. The chromosome number of Apetahia raiateensis (n = 14) is reported here for the first time, on the basis of a count made about 30 years ago by Peter Raven.