File:Contributions from the Botanical Laboratory, vol. 11 (1934) (20501595769).jpg

Title: Contributions from the Botanical Laboratory, vol. 11
Identifier: contributionsfro11univ (find matches)
Year: 1934 (1930s)
Authors: University of Pennsylvania. Botanical Laboratory; University of Pennsylvania. Morris Arboretum
Subjects: Botany; Botany
Publisher: Philadelphia : (s. n. )
Contributing Library: Penn State University
Digitizing Sponsor: Lyrasis Members and Sloan Foundation

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309 WILLIAM SEIFRIZ Ecology, Vol. 15, No. 3 in distinguishing the two. Juniperus communis occurs near the lake shore but is more frequent at higher altitudes. Its maximum height is rarely above five feet. Birches, as bush and prostrate forms, are abundant, especially at higher altitudes, but the lowland tree forms are not numerous. Among the latter are Betula pubescens, D. odorata (B. pubescens var. odorata) and B. ver- rucosa, of infrequent occurrence. B. kusmischeffii occurs higher up as a tree- shrub. It and B, odorata are hybrids. Two other birches of the Kola Pen- insula are B. tortuosa and B. nana, both typical of higher altitudes. AInus borealis and Popidus tremula occur as scattered specimens, the lat- ter being usually found as a small tree at higher altitudes. Sorbus aucuparia forms low bushes in moderate quantity. Neither Populus tremula nor Sorbus aucuparia characterize the arctic vegetation as strikingly as they do the moun- tain flora of the southern Soviet Provinces. The willows are abundant, but only in low forms being more typical of the higher slopes where they exist as prostrate plants. Among the nine or more species which are said to occur, Salix glauca is most abundant as a tree-shrub along the lake shore. With it occurs 5*. lapponica. Kreps and Kegel distinguish several types of forest associations at the lake shore, with pine and spruce as the dominant members. Pine is the more abundant and spruce exhibits greater variety in its associates. Kegel enumer- ates ten spruce associations distinguished by their undergrowth among which are Picetum myrtillosum, Picetum sphagnosum, and Picetum microbetulosa- empetrosum (fig. 4). Kegel mentions five pine associations but Kreps re- duces these to three: Pinetum sphagnosum, with Riibus chamaemorus, on wet ground; Pinetum hylocosum, with Plypnaceae, chiefly Hylocomium proliferum and Hypnum, and Vaccinium, on moist ground; and Pinetum cladoniosum, consisting of pine and numerous lichens chiefly Cladonia al- pestris, on dry ground. The spruce gets into all three of these associations and may replace the pine, thus forming the similar associations of Picetum sphagnosum, etc. The struggle between pine and spruce in the arctic is similar to that in the Caucasus.^ Pine predominates on dry, sandy, and rocky soil, and spruce on wet sand, but better on clay. There is little pure clay soil in this region and therefore few pure stands of spruce. The clay with its spruce is mixed more or less abundantly with the sand and its pine. Few if any areas exist which have not been repeatedly fire swept. In a fire, the spruce dies first because its large lower branches often sweep the ground and take root while the pine, with its high branches, more easily survives. The temperature fac- tor is also in favor of the pine for spruce seedlings freeze unless well pro- tected by a covering of larger growth, consequently, the pines come in first on ^Seifriz, W. 1932. Sketches of the vegetation of some southern provinces of Soviet Russia. III. Plant life in the Bakuriani Basin, Minor Caucasus. Jour. Ecology 20: 53-68. July, 1934 PLANT LIFE OF RUSSIAN LAPLAND 310 u n3 c C u O o u o CO C C S u I H o H-l
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