ENGELMANN — ADD. TO CACTUS-FLORA OF U. S. 197 



Addition's to the Cactus-Flora of the Territory of the 

 United States. By George Engelmann, M.D. 



Since my Synopsis of the Cactacece of the United States* 

 was published, Dr. J. S. Newberry, attached to Lieut. Ives' 

 Expedition to tlie ColoradoRiver, 1857-58, has elucidated 

 more fully the natural history of several species, heretofore 

 only imperfectly known.f In the same year, 1858, and the 

 following one, my brother, Henry Engelmann, Geologist to the 

 Expedition sent under Capt. Jas. H. Simpson, U. S. Topog. 

 Eng., to explore the best emigrant routes through the interior 

 of Utah, discovered in that interesting country a number of 

 new forms, which were placed in my hands for examination. 

 My report on them, illustrated by several plates from the 

 hands of our skillful artist, Mr. P. Roetter, was in due time 

 sent to the department; but the necessities of the country not 

 permitting the official publication, I have received permission 

 to communicate the substance of my investigations. 



1. Mamillaria vivipara, Haw. Engel. Syn. Cact., p. 13. 

 In the South Pass, and on Sweetwater River, no specimens 

 of this wide-spread species have turned up from the other 

 side of the great mountain chain. 



2. Echinocactus Simpsoni, spec, nov. : e basi turbinata 

 simplex, subglobosus seu depressus, mamilliferus; tuberculis 

 laxis ovatis oblique truncatis axilla nudis; areolis ovatis seu 

 ovato-lanceolatis, nascentibus albo-villosissimis mox nudatis ; 

 aculeis exterioribus sub-20 tenuibus rigidis rectis albidis, in- 

 terioribus 8-10 erecto-patulis robustioribus paulo longioribus 

 obscuris ; areola florifera sub tuberculi apice aculeis contigua 

 circulari ; floribus in vertice dissitis minoribus ; sepalis ovarii 

 paueis et tubi brevis inferioribus orbienlatis crenulatis, supe- 

 rioribus ovatis obtusis, petalis oblongis cuspidatis e virescente 

 roseis, stigmatibus 5-7 brevibus in capitulum globosum com- 

 pactis ; bacca parva sicca umbilico latissimo truncata flore 

 marcescente demura deciduo coronata ; seminibus paueis 

 magnis oblique obovatis minute tuberculatis. 



Var. ,3- mixor : tota planta, tuberculis, aculeis, seminibus 

 minoribus. 



Butte Valley, in the Utah Desert, and Kobe Valley, farther 

 west; var. ji. in Colorado Territory, e. g. in coarse gravel or 

 in crevices of rocks, abundant near Mount Vernon, at the base 

 of the mountains, Parry, Hall <b Harbour ; fl. in May, fir. in 

 July and August. With the New Mexican JEJ. papyracan- 



* Proceedings Amer. Acad. Arts &Sciences, Vol. III., p. 259-314; p. 

 344-346, Nov. 1856. 



f See my account in Lieut. Ives' Colorado River Expl. Exped., Wash- 

 ington, 1861, Botany, p. 12-14. 



