90 



LOWER F.nCEXr. FLORAS OF SOUTHEASTERN XORTH AMERICA. 



Anoiui Liniie iiiid Asiniina Ailaiison are kiH)Wii 

 with cortaiuty and both are present hi tlie 

 Wilcox flora. Seeds of Moiiodorospermum, 

 named from their resemblance to those of tlie 

 West African genus Monodora, are dcscrih(>d by 

 Warburij; from the late Tertiary of tlie Dutch 

 East Indi(>s (Banka). Tlie extinct .y;enus Jong- 

 mansia is based on seeds from the Dutch 

 Pliocene. 



The genus Anona includes 15 to 20 fossU 

 species, five of which arc also represented by 

 seeds. The oldest species comes from the 

 Dakota sandstone. A second species is found 

 in the late Cretaceous or early Eocene of the 

 Rocky Mountain province. The flora of the 

 Wilcox afl'ords a glimpse into the true stage of 

 evolution of Tertiary floras in that expanded 

 belt of the i\jnerican equatorial region which 

 was the center of radiation of so many recent 

 types. There were 4 exceedingly well-marked 

 species of Anona along the Wilcox coast, and 

 their leaves arc very common at some localities, 

 although no seeds have yet been discovered. I 

 assume that those Wilcox forms had habits 

 similar to those of most of the existing species, 

 exemplified by Anona glahra Linne, the pond 

 apple of Florida, which frequents shallow 

 fresh-water swamps, low shady hammocks, or 

 stream borders near the coast. Other species 

 occur in the low coppice association or on edges 

 of brackish swamps on the Bahamas. The 

 cultivated species, as the American Anona re- 

 ticulata Linne, which is planted in Guam, often 

 spread naturally along the inner beaches, 

 though attempts to introduce others of the 

 most liighly esteemed American species into the 

 Orient liave failed. From tlie prevalent habit 

 among the existing species, the growth in wet 

 shaded soils is evidently an old characteristic, 

 and as the Wilco.x anonas are associated with a 

 strand flora, the assumption that they gi'ow on 

 the inner beaches or the shaded and swampy 

 edges of lagoons possesses every degree of 

 probability. 



In the pipe clays of Alum Baj-, which are con- 

 temporaneous with the Wilcox, there are 2 

 species of Anona, and Engelhardt has described 

 2 species from the Eocene or Oligocene of Chile. 

 The Oligocene record shows a species in France 

 and another in Saxony. In the Miocene there 

 are 2 species each in England, Styria, and 

 Croatia, and 1 each in Boliemia, Transvlvania, 

 and Colorado. There is 1 species in the Plio- 



cene of France and 1 in that of Italy, which 

 shows how modern was their extinction in the 

 south of Europe. 



The genus Asiniina includes only 4 or 5 re- 

 corded fossil species, all American, except a 

 form from th(^ Pliocene of Italy, which has been 

 referred to this genus, althougli I suspect that 

 it represents an Anona, since Asiniina appears 

 to have originated in the Western Hemispliere 

 and been confined there. The oldest known 

 species is based on foliage from the basal Eocene 

 of the Kocky Mountains (Denver formation) 

 and of the enil)ayiiient (Midway formation). 

 One species is based on a seed from the basal 

 Wilcox and no other records have been found 

 except a form close to the modern from the late 

 Miocene of New Jersey (Bridgeton formation) 

 and the existing Asiniina triloba Dinial in the 

 interglacial beds of the Don Valley in Ontario. 



The order Papaverales (Rhoedales of Engler) 

 includes 6 families — Papaveracea>, Cruciferw, 

 CapparidacetB, Resedacea?, Tovariacea?, and 

 Moringacea% which together contahi about 255 

 genera and 2,200 species. The Papaveraceae 

 and Cruciferse are mostly herbaceous and widely 

 distributed, largely in the North Temperate 

 Zone, and they are of relatively recent evolu- 

 tion. The ResedacejB is a small family, largeh' 

 confined to the Mediterranean region. The 

 Capparidacea^, Tovariacere, and Moringacese 

 are mainly tropical. The last two families con- 

 sist, respectively, of a smgle genus and 2 species 

 of the American Tropics and a single genus and 

 3 species of the Asiatic Tropica — 1 ^yric-Arabian 

 and 2 East Indian. 



The family Capparidaceaj, which includes 

 about 35 genera and 400 existing species, is the 

 only one of the order represented in the Wilcox 

 flora. Most of the existing species are herba- 

 ceous. They are found on all the continents in 

 tropical and subtropiical regions. Five sub- 

 families are recognized. Of these the Cleo- 

 moidea= and (^apparidoideiB arc large and occur 

 on all the continents, including monotypic gen- 

 era in North America (Isomeris), South Amer- 

 ica (Stubelia, Atamisquea, Belencita), Africa 

 (Pteropetalum, Cladostemon), and Australia 

 (Roeperia, Apophyllum). The subfainOy Dip- 

 tcrvgioideio includes a single genus and oidy 5 

 or 6 species in Nubia, Arabia, and the Punjab. 

 The subfamily RoydsioidetB includes about a 

 dozen species, the genera Roydsia and vStixis 

 being confined to India and the genus Forcli- 



