Contributions in geographical exploration . this manner, developing the char-acteristic two-storied root system. The plants in which thisreaction was found were: Salix alaxensis, Salix nuttallii,Salix glauca, Echinopanax horridum (see page 188), Calama-grostis langsdorfii, Betiila rotiindifolia (feeble), Riibiis specta-bilis, Vaccinium ovalifoliiim, Deschampsia cccspitosa. STEM REACTIONS. The reactions of the aerial parts of plants remain to beconsidered. For the most part the new growth gives no indica-tion that unusual conditions were introduced in burial beyondthose incident to the merely m
Contributions in geographical exploration . this manner, developing the char-acteristic two-storied root system. The plants in which thisreaction was found were: Salix alaxensis, Salix nuttallii,Salix glauca, Echinopanax horridum (see page 188), Calama-grostis langsdorfii, Betiila rotiindifolia (feeble), Riibiis specta-bilis, Vaccinium ovalifoliiim, Deschampsia cccspitosa. STEM REACTIONS. The reactions of the aerial parts of plants remain to beconsidered. For the most part the new growth gives no indica-tion that unusual conditions were introduced in burial beyondthose incident to the merely mechanical action of the a few species show interesting reactions to burial. Themost conspicuous case is the pussy willow (Salix nuttallii).Before the eruption this grew as an erect bush two or threemeters tall. In many cases all parts above the ground werekilled in the eruption, but new shoots have been put out fromthe surface of the ash. These show no tendency to form newbranches like the original trunk, but spread out flat on the. Jan., 1919] Effects of the Eruption on Vegetation 203 ground, forming a rosette or mat. (Sec below.) An inves-tigation of the physiological causes by which this reaction isbrought about would yield exceedingly interesting results if onecould find the means of attacking the problem. A satisfactorysolution should throw much light on the causes underlying thedevelopment of prostrate shrubs in general, such as the pros-trate juniper of the north and the prostrate yew of our ownwoods, both forms being closely relat-^ -??oct growing species.
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