If a seed is subjected to the conditions required for germination and it fails to germinate, despite the fact that it is alive, then the seed is described as being dormant.
Seed dispersed in the late summer or autumn, without an inbuilt dormancy control, would normally germinate. The seedling would then have to survive unfavourable climatic conditions that more often than not would kill it. The plant has, therefore, developed a control mechanism that prevents the seed germinating until the onset of favourable conditions for germination and subsequent establishment. Although these controls benefit the plant and enhance the chances of successful seedling production, they present a very real problem to the gardener, who either has to wait for the dormancy to be broken naturally, which can
The seeds illustrated on pages 28-9 are as follows.
I Salix sp.; 2 luniperus deppeana; 3 Caragana arborescens; 4 Gleditsia x texana; 5 Cotoneaster horizontalis; 6 Corylus cornula var. californica;
17 Fraxinus americana; 18 Yucca data: 19 Eucalyptus fastigiata; 20 Populus iremontii var. fremontii; 21 Crataegus sp.; 22 Carpinus caroliniana; 23 Acacia melanoxylon; 24 Euonymus obovatus; 25 Malus floribunda; 26 Malus baccata; 27 Ulmus parvifolia-, 28 Cedrus libani; 29 Clematis virginiana; 30 Cytisus scoparius; 31 Viburnum alnifolium; 32 Taxus baccata; 33 Juglans cinerea; 34 Aesculus hippocastanum; 35 Rosa eglanteria; 36 Ceanothus americanus; 37 Catalpa speciosa; 38 Cornus racemosa.
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