The Revolution of 1861: The American Civil War in the Age of Nationalist Conflict. By Andre M. Fleche. (Chapel Hill, NC: University of North Carolina Press, 2012. Pp. xii, 224. $39.95.)

Cytogeography of the Humifusa clade of Opuntia s.s. Mill. 1754 (Cactaceae, Opuntioideae, Opuntieae): correlations with pleistocene refugia and morphological traits in a polyploid complex

“…Diploid refugia and polyploid formation – Polyploidy is very common within the Humifusa clade, occurring in 66% of the samples reported here. Most researchers that have studied Opuntia cytologically have found polyploid taxa (e.g., Bowden 1945a , Weedin and Powell 1978 , Pinkava et al 1985 , Doyle 1990 , Segura et al 2007 , Baker et al 2009a , b, Majure and Ribbens in press , but see Spencer 1955 ). All diploids in our analysis were restricted to either the southeastern or southwestern (eastern Texas and southeastern New Mexico) U.S., and the polyploid individuals were found nearly everywhere in between as well as north of these two diploid “refugia.” The disjunct pattern observed here in the Humifusa clade and in other studies between the southeastern U.S. and the southwestern U.S. is thought to have occurred as a result of the disruption of a semi-arid zone along the Gulf Coast region during the mid-Pleistocene (Webb 1990, Althoff and Pellmyr 2002 ).…”

“…Cytogeographic analysis – We mapped the localities for all of the individuals for which we determined ploidy (277 in number) and incorporated previous counts (n = 41) ( Bowden 1945a , Pinkava and McLeod 1971 , Pinkava et al 1973 , Weedin and Powell 1978 , Pinkava and Parfitt 1982 , Pinkava et al 1985 , Weedin et al 1989 , Doyle 1990 , Pinkava et al 1992 , Pinkava et al 1998 , Powell and Weedin 2001 , Baker et al 2009a , b; Majure and Ribbens in press ) to cover the majority of the geographic distribution of each taxon. This allowed us to explore the geographic boundaries of the different ploidal levels encountered in this clade and construct hypotheses regarding polyploid formation and speciation.…”

“…Thus, Opuntia humifusa s.l. is occasionally referred to as a species complex ( Doyle 1990 ). Currently, two taxa are recognized in Opuntia humifusa s.l.…”

“…Although chromosome counts have been reported for many of the Opuntia taxa from the southwestern U.S. and other areas ( Stockwell 1935 , Spencer 1955 , Pinkava and McLeod 1971 , Pinkava et al 1973 , 1977 ; Weedin and Powell 1978 , Pinkava and Parfitt 1982 , Pinkava et al 1985 , Weedin et al 1989 , Pinkava et al 1992 , Powell and Weedin 2001 , Pinkava 2002, Negrón-Ortiz 2007 , Segura et al 2007 , Baker et al 2009a , b), few chromosome counts have been reported for taxa of Opuntia in the eastern and midwestern U.S. ( Majure and Ribbens in press ), and most of those taxa belong to the Humifusa clade. Bowden (1945a, b), Hanks and Fairbrothers (1969) , Doyle (1990) , and Baker et al (2009 a, b) have all made counts of members of the Humifusa clade from the eastern U.S. Bowden (1945a, b), Doyle (1990) , and Baker et al (2009a) recorded diploid (2 n = 22) and tetraploid (2 n = 44) material of Opuntia humifusa from the eastern U.S., and Bowden (1945a) recorded tetraploid (2 n = 44) material of Opuntia impedita (currently syn. of Opuntia pusilla ).…”