DISTEIBUTION OE THE MOEE PEOMINENT NATUEAL OEDEES. 259 



is the greatest generic concentration of the order; for California possesses only eleven 

 species, belonging to four genera, one of them an endemic monotype. 



Phytolaccacece. 

 This small, though widely spread and somewhat heterogeneous order is represented 

 by eight out of twenty genera and ten species. These include the new monotype 

 Phaulothamnus recently discovered in North Mexico. Excluding Phytolacca itself, the 

 genera are peculiar to America and five of them are monotypes. Agdestis, one of them, 

 is Texano-Mexican, and Stegnosperma is found in Sonora, Lower California, Guatemala, 

 Cuba, and San Domingo. 



Polygonacece. 

 Excluding the Eupolygoneae and the Rumiceae, which are abundantly represented by 

 the widely-spread genera Polygonum and Mumex, this order is essentially American. 

 Indeed all the genera of the tribes Eriogoneae, Kcenigiese, Coccolobeaa, and TriplarideEe 

 are American, and fifteen out of nineteen are peculiar to America. The exceptions are 

 one species of Kcenigia in the arctic regions and one in the Himalaya ; the genus 

 MuehlenlecMa in Australasia and Polynesia, one species of Brunnichla in west tropical 

 Africa, and one imperfectly known species of Symmeria in Senegambia. The Eriogoneae 

 are almost wholly western, chiefly Californian, with a few Chilian species of the same 

 genera. JEriogonum itself comprises about 100 species, all North American ; two of them 

 are found east of the Mississippi river; both inhabit Florida and one extends to South 

 Carolina. Upwards of fifty are peculiar to California ; and of the nineteen found in 

 Mexico fifteen are merely southward extensions of species more abundant north of 

 Mexico. Only one, E. undulatum, has been discovered in South Mexico ; and it is 

 probably rare, for we have seen only one imperfect specimen, collected by Galeotti at 

 Real del Monte at an elevation of 8000 feet. The Californian and Chilian genus 

 Ckorizanthe is represented by one species on the Gila, though perhaps not within our 

 limits. Besides the genera mentioned there are six others of this affinity in California, 

 two of which reappear in Chili. Passing to the Coccolobese we have the showy endemic 

 genus Antigonon, Campderia (which is also Brazilian), a few species of the large 

 tropical- American genus Coccoloba, and two species of MuehlenbecJcia. In TriplarideEe 

 we have the endemic monotypic Podopterus, and two species each of Triplaris and 

 Ruprechtia ; both more numerous in species in South America and the former repre- 

 sented in the West Indies. 



Piperacece. 



Both Piper and Peperomia, generally diffused tropical genera, are numerous in 

 Mexico and Central America, yet we suspect that the two hundred or more species 

 described are susceptible of very considerable reduction. Houttuyina, the only other 



biol. CEN-TK.-AMEK., Bot. Vol. IV., August 1887. 2 m 



