120 



The Journal of Heredity 



In ])rcsenting a summary of the families 

 of palms in 1913, it aijpeared that 13 

 families are fovmd on the American 

 Continent and only 5 other families in 

 the Eastern Hemisphere. - 



If now the date palms arc to be with- 

 drawn from the Old World scries and 

 added to the New, we shall have the 

 more reason to entertain the idea that 

 this order of plant life had its orij^in and 

 evolution somewhere on this side of the 

 globe. It is also ]jossible to distinguish 

 a North American scries of families 

 from a South American series. To 

 judge from the contrasts presented by 

 the existing forms, North and South 

 America have had separate palm floras 

 for periods that must have been very 

 long in com]mrison with the time that 

 has elapsed since the continents were 

 joined, for most of the palms that 

 api:)ear to ha\'e traveled along the 

 Isthmus have occupied as yet only a 

 small ijart of the regions that are now 

 accessible to them. 



FAN-PALMS WITH SEEDS LIKE DATES. 



With these general considerations in 

 mind we can better appreciate the 

 interest of the fact that some of the 

 American fan-palms have seeds rather 

 closely similar to those of the date 

 palm. This is most notably the case 

 with the genus Brahea, where the seed 

 is of the same general form and has 

 a distinct longitudinal groove. The 

 Florida saw-jjalmctto iSerenoa serru- 

 lata) also has fleshy date-like fruits, 

 with seeds of the same general shape 

 and external ap];)earance, but lacking 

 the longitudinal groove. 



While the seeds describe;! by Dr. 

 Berry could not be referred t(^ the genus 

 Brahea on account of the jjosition of the 

 embryo and the dejjth of the longitu- 

 dinal groove,' such di (Terences are often 

 found in closely related genera. Neither 

 should too much weight be placed u])on 

 the elongate form of the seeds, which 

 gives them so much similarity to the 

 seeds of the familiar commercial varie- 

 ties of dates. Some species of Phoenix 



have the fruits almost spherical, and 

 this is true also of some of the varieties 

 of Phoenix dactylijcra. 



The similarity shown by the seeds of 

 Brahea is at least sufflcient to indicate 

 that the form of the seeds is not a unique 

 characteristic of the date palms, but a 

 feature that may have been shared with 

 older relatives now extinct. Unless the 

 fossil remains arc of a character to 

 exclude such a possibility it will be 

 easier to believe that the .seeds found in 

 Texas ma\' rc]jrescnt some collateral 

 relative of the date, perhaps even a fan- 

 palm, rather than a true member of the 

 genus Phoenix. Dr. Berry appears to 

 have provided for this contingency by 

 naming his fossils as Phoenicites occiden- 

 talis, instead of referring them to the 

 genus Phoenix. Fossil jjalm leaves 

 have been found in many localities in 

 the western States, and even in Alaska. 

 The fact that these were fan-palms need 

 not be supposed to exclude the possi- 

 bility that some of them may have 

 borne date-like fruits, or that they may 

 have spread as fan-])alms to the Old 

 World. The Polynesian fan-palms that 

 have been described under the name 

 Pritchardia and the Asiatic genus Livis- 

 tona appear to have rather close relatives 

 among the American fan-palms. 



PRIMITIVE AMERICAN PALMS. 



If the date ]jalms originated in 

 America or reached this continent at 

 some later period it is difficult to under- 

 stand why they should have become 

 extinct, in view of the fact that some of 

 the most primitive types of fan-palms 

 have continued to exist in Florida, the 

 West Indies and Central America. 

 Moreover, a considerable nmnber of the 

 related American fan-palms, including 

 such genera as Inodcs, Brahea, Erythea 

 and Washingtonia, live in open, desert 

 regions, and hax'e the same habits and 

 ecological requirements as the date 

 ])alms. The similarities extend to the 

 l^roduction of fruits with fleshy, edible 

 ])ericar]5s, not as thick or as sweet as 

 those of the date ]jalms, but nevcrthe- 



* Cook, f ). F., Relationships of ihc False Date Palm of the Florida Keys, with a .Synoptical 

 Key to the Families of American Palms. Contr. U. S. Nat. Her!)., vol. 16^ pt. 8, IQl.S. 



'Drawings of the seeds found by Berry were published in the Joiknal of Hekkoity, V, 11, 

 499, Nov.. 1014. 



