CONTRIBUTIONS TO WESTERN BOTANY NO. 16 



Erysimum elatum. Ramsey Canon, Huachuca mountains, Arizona. Sep- 



Arabis porphyrea. No. 24841. Ramsey Canon, Huachuca mountains, Ari- 

 zona. September 29, 1929. This is a dubious species. 

 Draba petrophila. No. 24842. Ramsey Canon, Huachuca mountains, Ari- 

 zona. September 28, 1929. This appears to be a good species, grow- 

 ing only on the rocks. 

 Streptanthus tortuosus. No. 24844. Mono Lake, California. June 29, 

 1929. 



ia refracta. No. 24843. Sacaton, Arizona. October 2, 1929. 



I Parisian. No. 24845. Arrowhead Lake, California. August 4, 



Uerbtris Wilcoxii. No. 24S46. Ramsey Canon, Huachuca mountains, Ari- 

 Seeptember 28, 1929. 



scopulorum. No. 24847. Ramsey Canon, Huachuca moun- 

 Arizona. September 29, 1929. 

 Drummondi. No. 24848. Ajo, Arizona. September 18, 1929. 

 Monnina Wrightii. No. 24849. Ramsey Canon, Arizona. September 30, 



1929. 

 Thalictrum Wrightii. No. 24850. Ramsey Canon, Huachuca mountains. 



.^-"ftrizona. Seeptember 28, 1929. 

 'Viola Canadensis. No. 24851. Ramsev Canon, Huachuca mountains, Ari- 

 ^^na. September 28, 1929. 



"Euphorbia serpens H. B. K. No. 2 -IS 5 I. lU,ro<iui\o;-i mountains, Ari- 

 zona. September 22, 1929. No. 24853. Pichacho Tass. October 2, 

 1929. No. 24854. Miller Canon, Huachuca mountains, Arizona. 

 October 1 , 1929. Curiously Wooton and Standley p. 398 of their Flora of 

 New Mexico put this species under annuals, when it is a woody rooted 

 and rooting perennial. This species is common on little slopes along 

 rivulets or in gulches where there i- c > l .':■ ..;■■ - in gravelly places. 

 The mats often cover a space two yards wide, and they root at almost 

 every joint, a character not found in any other species of Euphorbia. 

 The mternodes are rather long on the main stems and are filiform 

 and smooth. The pap- and mo.tlv entire ' 



conspicuous. The leaves vary from obliquely oval to almost round, 

 and are entire, rather leathery and obtuse, and mostly half an inch 

 long when fully developed. The ul short and with 



imbricated leaves, and with the mostly single flowers about sessile 

 among the leaves. The pods are sharp-angled and smooth, and about 

 1.5 mm. long, the seeds are orange-colored, nearly 1 mm. long, rather 

 narrowly oblong, but a trifle narrower at tip but not at all ovate, 

 smoo i h - \ : tw pits, obtusely triquetrous and with 



rounded back and deeply furrowed face. The appendages are white 

 or pinkish remform to obliquely and transversely oblong ^and about as 

 wide as the pod is long, the glands are purple or black and trans- 

 versely oblong. The inflorescence is terminal ,-•■■!■..: and 

 always congested, and very late in ; a] , - nC e 



