626 



SCIENGK 



[N. S. Vol. YII. Ko. 175. 



Ephedra. 

 (No Picea.) 



(NoPinus.) 

 (No Ferns ) 

 Equiseiuni, sp. 



Puccioia evadens,?. sphjeralcese* 



Streptopus amplexifolius. 

 Veratrum Californlcum. 

 Phleum pratense (ex. cult). 

 JuQiperus communis. 

 Picea Engelmanni. 

 Picea pungens. 

 Pmus ponderoaa scopulorum. 

 Pieris aquilina. 

 Equisetum arvense. 

 Equisetum hiemale. 

 Marchanlia po'.yiiiorpha. 

 Pucciuia reratri. 

 "Csnea barbara. 



I have not given very mucli study to the 

 flora of Mesilla, because my friend, Pro- 

 fessor E. O. Wooton, is working upon it, so 

 it may be that there exist a few better rep- 

 resentatives than I have cited. I have, 

 however, examined the flora a good deal in 

 my searches for insects, so it is not prob- 

 able that much change would be necessary. 

 It will readily be appreciated that if the 

 Colorado species had been found as fossils, 

 and another bed in Xew Mexico, rich in 

 plant remains, had shown no more resem- 

 blance to the first than is here shown, geol- 

 ogists would have been very ready to assign 

 different ages to the beds. 



Local lists of plants, as ordinarily pub- 

 lished, do not sufiiciently bring out the dif- 

 ferences between florulse . In the first 

 place, collectors will often mix up two or 

 three fiorulte in one list ; in the second, in 

 the effort to make a complete list, they will 

 include plants which are either extremely 

 rare or actual aliens. In these days of 

 railroad travel, it seems common to see near 

 railway lines, and in other places, little 

 colonies of plants out of their proper en- 

 vironment, which persist a while and then 

 perish. 



I now propose to show that such dif- 

 ferences as above indicated do not only 

 occur between the recognized zones, but 

 within the limits of the same zone. 



In Mesilla, !N"ew Mexico, on June IS, 

 1897, I collected weeds in the cultivated 

 ground of the Casad orchard. I give the 

 list; and in a parallel column a list from 

 the sandhills, also in Mesilla, choosing as 



nearly representative plants as I can. For 

 the determinations of many of the plants I 

 am indebted to Professor E. O. Wooton. 



Cultivated Gbouxd, Mesiixa. Sandhills. Mesilla. 



Anoda hastata. 

 Sp;iceralcea angustifolia. 

 Sida bederacea. 

 Gaura parviflora, 

 Glyc.vrrhiza lepidota. 

 Sopbora sericea. 

 Melilotusiodica. 

 Eranseria Hookeriana. 

 Baccbaris glutinosa. 

 Astera tanacetifolius. 

 Heliantlius ci iaris. 

 HelianthuB aunuus. 

 Aster spinosu"'. 

 Lepacbys ta^etes. 

 Flaveria repauda. 

 Xanthium Canadense. 

 Erige on Caaadensis. 

 Verbeslna encelioldes. 

 Apbanostepbus ramosissimus. 

 Curcubita fcetid:ssima. 

 Ipomcea Mesicana. 

 Cuscuta (C. Californica ?). 

 Salvia lanceolata, 

 Piiysalis (P. lanceolata ?) 

 Solanum eljeagnlfolium. 

 Portulaca oleracea or retu^a. 

 Acantbocbiton Wrigbtii. 



Cbenopodium leptopbyllum. 



Men zelia multiflora. 

 Ditbyrjei WislizenlL 



CEnothera pallida 



Bales scoparia. 



Delea lanosa 



Prosopis juliflora glaidulosa. 



Aster tanacetifolius. 

 A~ter canescens. 

 Artemisia, sp. 



Lepacbys Tagetes. 

 Pectis papposa. 

 Plucbea bor-^alis. 

 Eigelovia Wrigbtii. 

 Baileya multiradiata. 

 Aplopappus spinulosus. 

 Maurandia Wislizenii. 

 Abronia turbinata. 

 Abronia cycloptera. 

 Kama bispidum. 

 Pbacelia integrifolia. 

 GDia, sp. 

 Eriogonum, sp. 

 Acantbocbiton Wrightii. 

 Atriples canescens. 

 Oryzopsis membranacea. 

 Epbedra, sp. 



The sandhill list could readily be ex- 

 tended by further study. The purpose just 

 now is merely to show that two radically 

 different floras occur in the same immediate 

 vicinity, at the same altitude, on diflPerent 

 kinds of soil. Cultivated lands here vary 

 from the very sandy to the almost pure 

 adobe, and it may be assumed that they are 

 thus adapted for very different crops, and 

 require different methods of cultivation. 



It will be at once remarked, from the 

 data given in this and the preceding paper, 

 that two quite different factors have had to 

 do with the modification of the flora. In 

 the one case the principal factor is the cli- 

 mate, in the other the soil. ;N"evertheles8, 

 the two are intimately connected, for the 

 soil greatly modifies the effect of the cli- 

 mate. Another very important factor is 

 shade, which is present in the Colorado 

 case. Moisture, again, is controlled partly 

 by the general climate and partly by the 



