106 J. E. CRIBBS 



reaction upon the stem and foliage, and the tree either fails to 

 develop further or gradually dies. , 



The pioneer tree species are, as a rule, the dominant ones 

 throughout the deciduous stage, especially when it is succeeded 

 by an evergreen one. Accompanying these may also be found, 

 Betula lutea, Larix laricina and Ulmus americana. The latter 

 form being found here but rarely and then usually associated 

 with slight elevations. 



The undergrowth of shrubs and tree seedlings is commonly 

 very dense, and may make passage through this stage quite 

 difficult. The essential forms represented here are; — Rhus 

 vernix, Rhus toxicodendron, Hamamelis, virginiana, Vaccinium 

 corymbosum, Cornus stolonifera, Rhododendron canadense, Rosa 

 Carolina, Prunus virginiana and Alnus incana. With these 

 occur the seedlings of Betula, Fraxinus and Acer. 



The herbaceous representatives include, Viola cucullata, 

 Viola pollens, Caltha palustris. Sphagnum, Cirsium muticum, 

 Lactuca spicata. Polygonum sagittatum. Polygonum arifolium, 

 Symplocarpus foetidus, Arisaema triphyllum, Veratrum viride. 

 Ranunculus septentrionalis, Ranunculus recurvatus. Ranunculus 

 abortivus, Senecio aureus, Polemonium reptans, Mnium, etc. 

 These are characteristic of the depressions while upon the broad 

 hummocks of the same area are found Rubus idaeus, Medeola 

 virginiana, Trillium erectum, Mitella diphylla, Cypripedium 

 parviflorum, Dentaria diphylla. Polygonum biflorum, Maianthemum 

 canadense, Osmorrhiza longistylis, Circaea lutetiana, Aspidium 

 spinulosum, Aralia nudicaulis, Osmunda cinnamomea, Osmunda 

 Claytoniana, Onoclea sensibilis, Aspidium cristatum. Geranium 

 maculatum, etc. 



Larix laricina, which belongs to the deciduous zone, although 

 of the coniferous type, commonly assumes a position on the 

 inner edge of the zone, adjacent to the true evergreen species. 

 When Larix is strongly represented there rarely occurs any 

 deciduous swamp forest of the broad leaved type, except possibly 

 a narrow fringe of more or less scattered forms. This means that 

 Larix infringes upon the shrubs, and that the position occupied 

 by Fraxinus, Betula and Acer is, in this instance, largely taken 

 by the tamarack. 



