THE DECIDUOUS FOREST CLIMAX. 207 



which pass into pine forest, and the latter yields to oak forest of Q. digiiata, 

 alba, cocdnea, and nigra, with occasional Hicoria ovata. 



Harvey (1903 : 29) has sketched the following stages in the rock prisere of 

 Mount Katahdin, Maine: 



The pioneer crustose-lichen stage consists chiefly of Buellia geographica, 

 which is followed by the foliose stage in which Unibilicaria is prominent, and 

 by mosses, Rhacomitrium, Andreaea, etc. The fruticose lichen associes con- 

 sists of Cladonia rangiferina and Cetraria islandica primarily, with Cladonia 

 cristatella and several mosses. The accimiulation of soil permits the develop- 

 ment of a grass community, called alpLae tundra, of Hierochloe alpina, Agrostis 

 rubra, Deschampsia Jlexuosa, Carex spp. and Juncus trifidus, and especially of 

 Polytrichum spp. The heath stage is characterized by Empetrum nigrum, 

 Vacdnium spp., and Diapensia lapponica. Ledum, Kalmia, Arctostaphyltis, 

 Rhododendron, Bryanihus, Loiseleuria, and Cassiope are also dominant or fre- 

 quent. In the scrub stage, Betula papyrifera minor and B. glandulosa are the 

 first to appear, lying prostrate. Locally, Larix americana and Juniperus 

 communis nana are the first comers. This stage is followed by the Picea-Abies 

 climax forest, with an undergrowth of Cornus canadensis, Chiogenes serpylli- 

 folia, Coptis trifolia, Ldnnaea borealis, Trientalis americana, Oxalis acetosella, 

 Moneses grandiflora, Streptopus roseus, Clintonia borealis, etc. In addition to 

 the dominants, Picea nigra and Abies balsamea, Betula papyrifera, Alnus 

 tdridis, and Thuja ocddentalis are secondary constituents. 



In warm, moist situations, especially upon talus, the sere is initiated by 

 Sdrpus caespitosus, followed by Campanula rotundifolia and Solidago virgaurea 

 alpina, together with Potentilla tridentata, P. fruticosa, Arenaria groenlandica, 

 Carex sdrpoidea, Luzula spadicea, L. spicata, and Juncus articulatus. The 

 meadow stage, which develops next, is introduced by Castillda pallida, Ana- 

 phalis margaritacea. Aster spp., etc. The grasses next appear, chiefly Cala- 

 magrostis canadensis, C. langsdorfii, and Bromus ciliatus, with Glyceria nervata, 

 Agropyrum violaceum and Agrostis rubra also conunon. The shrub stage is 

 initiated by the dominant Diervilla trifida, followed by Spiraea salidfolia, and 

 by the less abundant Rubus strigosus, R. canadensis, Lonicera coerulea, and 

 Ribes prostratum; Alnus viridis next becomes dominant, and the scrub gradu- 

 ally passes into the climax forest. 



Ganong (1906 : 81) has described the development of the climax forest on 

 the new beach of Grande Plaine, New Brunswick: 



The pioneers of the open beach are Salsola, Cakile, Mertensia, and Lathyru^, 

 in the order of their abundance. On the grass plain behind, Ammophila is the 

 dominant, with which are associated Carex silicea, such ruderals as Taraxacum, 

 Cnicus, Sonchus, Rumex, etc. Beyond the plain, the leeward slope is more 

 abundantly covered with the same species, while the hollows are first colonized 

 by Fragaria virginiana, followed by Festuca rubra. The sheltered slopes are 

 characterized by Juniperus, Myrica, and Hudsonia. The swales between the 

 plains and the woods constitute a transition zone, marked by alternating areas 

 of meadow and juniper mats. In the latter develop the first trees of Picea 

 alba, while the meadows consist of Festuca, Poa, Agrostis, Juncus, Carex, etc. 

 These are followed by the sandy woods of Picea, which pass into the closed 

 mixed woods of spruce, Abies balsamea, Acer rubrum, Populus, Betula, etc. 



Jennings (1908, 1909) has recognized the following sequences in the littoral 

 sand sere on the southern coast of Lake Erie: 



