A. PHYLLOSTEGIA. 



267 



MINOR VARIATIONS AND SYNONYMS. 



1. Atriplex covillei Macbride, Contr. Gray Herb. N. S. 53:11, 1918. — Based upon Endolepis covillei, 

 which see in this list. 



2. A. DHACONis Jones, Contr. West. Bot. 8:40, 1898. — Characterized by an exceptional development of the 

 basal lobes of the fruiting bracts. These lobes are wing-like and more or less laciniate, sometimes also with 

 green ridges or teeth along their sides which "give the fruit a fantastic appearance, of halberd shape." These 

 characters are exceedingly variable even on individual plants. In the type specimens many of the bracts have 

 developed neither wings nor appendages, but are entirely smooth and narrowed to the base. The type of draconis 

 was described as dioecious and the specimens exhibit a strong tendency to dioecism, but they are not purely so, 

 the pistillate plants having a few staminate flowers, while at least some of the staminate plants are well supplied 

 with pistillate flowers. The bracts of these latter, however, are only 2 to 4 mm. long and either arrested in 

 their development or immature. The types came from between Wadsworth and Clarks, western Nevada, 

 according to Professor Jones, the collector, who has himself made the reduction of his species to phyllostegia 

 (Jones, Contr. West. Bot. 11:20, 1903). 



3. Endolepis covillei Standley, N. Am. Fl. 21 : 73, 1916.— The same as A. phyllostegia. Based upon plants 

 in which a few scales, representing a reduced perianth, were found between the bracts of the pistillate flowers. 

 Fully discussed under Relationships. 



4. E. PHYLLOSTEGIA Rydberg, Bull. Torr. Club 39:312, 1912.— Based upon Obione phyllostegia Torrey (No. 

 5 of this list). Transferred because of the presence of a perianth in some pistillate flowers. 



5. Obione phyllostegia Torrey, in Watson, Botany King's Expl. 291, 1874. — The original name for A. 

 phyllostegia. 



RELATIONSHIPS. 



There is little doubt that Atriplex phyllostegia is very closely related to A. dioeca. It 

 may, in fact, be a direct development from this, as is suggested by the frequent appear- 

 ance of perianth scales in the pistillate flowers. These structures are only vestiges, 

 apparently, even in dioeca, and phyllostegia may therefore be taken as the more advanced 

 type, since they are sometimes present and sometimes entirely suppressed. The present 

 species is the more highly specialized, as is shown by the remarkable development of 

 unique features of the leaves and bracts, a notable tendency toward dioecism, and cer- 

 tain other details. (The other species is strictly monoecious, notwithstanding its 

 name.) While A. phyllostegia is much like some forms of the argentea group in technical 

 characters, there is no evidence that it was the starting point of these. The develop- 

 ment of unusual features, especially the arrow-like foliage, indicates rather that it is the 

 terminus of a short lateral branch of the evolutionary tree. 



Perhaps nowhere in the three genera here treated is there a better example of the 

 futility of attempts to establish and maintain genera on trivial characters than is fur- 

 nished by the so-called genus Endolepis, to which a part of A. phyllostegia recently has 

 been transferred. The unnecessary increase in synonymy and the resulting confusion 

 which results from the incomplete examination of material is likewise well illustrated here. 

 All of the opinions now to be cited are those of leading systematists. The differences in 

 opinion and treatment may be taken, therefore, as an index of the efficiency of taxonomic 

 methods, although it should be noted that the earlier workers were handicapped by a 

 lack of abundant material. 



Endolepis was first proposed as a genus by Torrey (in Gray, Pacif. R. R. Rep. 12^:47, 

 1860), with E. suckleyi as the only species. This is exactly the same as Kochia dioeca 

 Nuttall, or Atriplex dioeca, as it is now called, the earlier Nuttallian name having been 

 apparently overlooked. Torrey characterized his genus especially by "the remarkable 

 calyx of the staminate flowers, and by the presence of a manifest 3-sepalous calyx in the 

 fertile flowers." The feature of the staminate calyx still holds for dioeca and its close 

 associate, monilifera. But the presence of a calyx in the pistillate flowers is of value as 

 a character only as it furnishes a clue to relationships and shows how closely Endolepis 

 is connected with Atriplex. The evidence of this is found in A. phyllostegia, described by 

 Torrey 14 years after he established Endolepis. No calyx was found in the pistillate 

 flowers at the time, but it is now well known that the calyx, which consists of a few 



