68 IOWA ACADEMY OP SCIENCES. 



nica Americana and Mimuhis Lewsii. Along the banks of 

 the streams Primula Parryi and Aqiiilegia caerulea, the 

 Mertensia Sibirica, often forming great festoons over the 

 banks of the stream, and with it in the little bogs we find 

 ISaxifrarja punctata, Aconitum Columhianum, Trollius laxus 

 and Caltha hptosepala, with Juncus, Salix macrocarpum, 

 Gentiana heterosepala,Su-ertiaperenn is and ErigeroncilaheJlus. 

 Mosses are numerous, of gY?iSses Phleuui aJpinuin, Deschawp- 

 sia and Poa epilis. In the drier portions of these canons, as 

 well as the marsh, the Picea Engelmannii and Pinus Mur- 

 rai/ana, but especially the Picea Engelmannii occur. In still 

 drier situations the Pinus Murray ana and Abies subalpina, 

 Vaccinium caespitosum, Pacliystima Myrsinites, Arctostaphy- 

 los Uva-ursi and occasionally the Ledum glandulosum 

 occur. The Vaccinium caespitosum, Bubus strigosus, 

 Arcoostaphylos and Rihes dicaricatum var. ii riguum, Trifo- 

 lium Parryii and T. dasypldlum and T. lonr/ipjps are com- 

 mon in the Engelmann spruce belt. The clovers and 

 Rihes, Rubus and huckleberry occur up to timber line. 



At the timber line we have a large aggregation of plants 

 that have a short blooming period; the soil is moist when 

 the sun disappears, and we have Alpine gardens formed. 

 Of these plants we may mention OuipJialodes, Geum Rossii, 

 Acquilegia caerulea dwarf form, Dodecatheon media, var. and 

 Primula Parryi. -At very high altitude Salix reticulata, S. 

 Artica var, petraea, Parrya nudicaulis var. glabra, Draba 

 streptoc(irpa,Polemonium confertum andseveral speciesof Sax- 

 ifraga like S. nivalis, Silene acaule, Erigeron and Erigon)im. 

 The dwarf Picea Engelmannii and Abies subalpina are com- 

 mon above the timber line. The Engelmann spruce extend- 

 ing up further than Abies subalpina. The short blooming 

 period protects these plants from the dry conditions that 

 prevail later, the seeds ripen and mature in a short time. 

 Most of the plants have a strong root stock which protects 

 them not only from the drouth, but from the cold of winter 



