STAND ley: a new GENUS OF CHENOPODIACEAE 59 



Zuckia is not very closely related to the species of Spinacia, which are 

 glabrous annuals with indurated bracts, 4 or 5 stigmas, and vertical 

 seeds. Suckleya, too, is an herbaceous plant with strongly obcom- 

 pressed bracts and vertical seeds. Only two other genera are included 

 in the subtribe Atriplicinae : Endolepis and Atriplex. Endolepis 

 has been included in Atriplex by most authors, but it seems to the writer 

 sufficiently distinct in having a perianth in the pistillate flowers, a 

 character which, along with its vertical seeds, also separates it from 

 Zuckia. ^ 



Apparently this new genus is most closely related to Atriplex, but 

 in the latter the bracts are never wholly united; at least the tips are 

 always free, and commonly the bracts are distinct at least to the 

 middle, often nearly or quite to the base. In Zuckia they are wholly 

 united, and at the depressed apex there is only a very small aperture 

 through which the styles are exserted. In only a small group of 

 Atriplex species — 'the subgenus Dichospermum Dum., which contains 

 the type of the genus, A. hortensis — ^are horizontal seeds found. In 

 these species there are two kinds of pistillate flowers on each plant: 

 some with vertical seeds inclosed by two distinct bracts, and others 

 with horizontal seeds mclosed in a regular herbaceous calyx. In 

 Zuckia all the pistillate flowers are alike, having the horizontal seed 

 included in the somewhat inflated bracts, with no calyx present. As 

 already noted, Zuckia bears a superficial resemblance to Grayia brand- 

 egei, the two being almost exactly alike in habit and leaf form; but the 

 species of Grayia have a copious pubescence of small branched hairs, 

 and, of course, the structure of the pistillate flowers and the fruit is 

 very different. 



Zuckia is evidently a very distinct genus and one of the most re- 

 markable members of the whole tribe. That it was not found by some 

 of the earlier collectors who visited this region is rather strange, but 

 doubtless attributable to the circumstance that the two localities 

 whence it now comes are in a part of Arizona in which comparatively 

 little collecting has been carried on. This and the fact that so much crit- 

 ical attention has been given recently to the Chenopodiaceae, without 

 the discovery of this new generic type, lead to the belief that Zuckia is 

 generally wanting in herbaria. Its rediscovery and collection in ade- 

 quate amount for distribution will be a matter of much interest; for, 

 while many new genera have been proposed in recent years for United 

 States plants removed* from well known genera, the opportunity 

 rarely arises of establishing a genus of phanerogams upon a plant 

 previously quite unknown. 



