ESTIMATION OF THE HEAT NECESSARY TO GROWTH. 



559 



add together the daily maxima of sun-temperatures from the first of January 

 until the event in question takes place. 



A selection of constants obtained in this way from observations extending over 

 many years in Central Germany (Giessen) may be suitably inserted here. 



Constants for the Issue of the Foliage-leaves from the Buds. 



Gooseberry {Rihes Grossularia) 478° 

 Hazel {Cori/lus Avellana) 1061°. 

 Beech {Fagus silvatica) 1439°. 



Plane {Platanus acerifolia) 1503°. 

 Walnut (Juglans regia) 1584°. 



Constants for the Opening of the First Flowers. 



Hazel {Corylus Avellana) 226°. 



Mezereon {Daphne Mezereum) 303°. 



Snowdrop {Oalanthits nivalis) 311°. 



Sweet Violet ( Viola odorata) 576°. 



Cornel {Cornus mas) 576°. 



Apricot {Prufius Armeniaca) 843°. 



Corydalis {Corydalis cava) 863°. 



Violet Willow {Salix Daplinoides) 968°. 



Cowslip {Primula ireris) 968°. 



Norway Maple {Acer platanoides) 1100°. 



Peach {Persica vulgaris) 1100°. 



Gooseberry {Ribes Grossularia) 1138°. 



Almond {Amygdalus communis) 1196°. 



Gean {Prunus avium) 1265°. 



Sloe {Prunus spinosa) 1265°. 



Pear {Pirus communis) 1304°. 



Bird Cherry {Prunus Padus) 1325°. 



Apple {Pirus Malm) 1423°. 



Plum {Prunus domestica) 1423°. 



Alpine Woodbine {Lonicera alpigena) 1458°. 



Oak {Quercus pedunculata) 1556°. 



Lilac {Syringa vulgaris) 1556°. 



Walnut {Juglans regia) 1584°. 



Barberry {Berberis vulgaris) 1615°. 



Poet's Narcissus {Narcissus poeticus) 1615°. 



Hawthorn {Cratoegus Oxyacantha) 1649°. 



Lily of the Valley {Convallaria majalis) 1649°. 



Horse Ch^stmit {JEsculus Hippocastanum) 1708°, 



Peony {Pceonia officinalis) 1818°. 



Laburnum {Cytisus Laburnum) 1818°. 



Mountain Ash {Sorbus aucuparia) 1844°. 



Norway Spruce {Abies excelsa) 1904°. 



Vla.'ne {Platanus acerifolia) i\lti° . 



Elder {Sambucus nigra) 2313°. 



Deadly Nightshade {Atropa Belladonna) 2346°. 



Acacia {Robinia Pseudacada) 2404°. 



Scotch Pine {Pinus sylvestris) 2404°. 



White Water Lily {Nympkcsa alba) 2506°. 



Arnica montana 2538°. 



Tulip Tree {Liriodendron tulipifera) 2538°. 



Rosa centifolia 2538°. 



Fox-glove {Digitalis purpurea) 2640°. 



Carthusian 'Pxak{Dianthus Cartkusianorum)26iO''. 



Vine ( Vitis vinifera) 2878°. 



Broad -leaved Lime {Tilia grandifolia) 3033°. 



Small-leaved Lime {Tilia parmfolia) 3274°. 



Oat {Avena sativa) 3444°. 



White Lily {Lilium candidum) 3378°. 



Chestnut {Castanea sativa) 3660°. 



Immortelle {Helichrysum arenarium) 3918°. 



Ling {Calluna vulgaris) 4164°. 



Trumpet-tree {Catalpa syringcefolia) 4275°. 



Blue Aster {Aster Amellus) 4874°. 



Syrian Marsh-Mallow {Hibiscus Syriacus) 4986°. 



Meadow Saffron {Colchicum autumnale) 5024°. 



Ivy {Hedera Helix) 5910°. 



Constants for the Eipening of Fruit. 



Wild Stra-wberry {Fragaria vesca) 2671°. 

 Gean {Prunus avium) 2778°. 

 Mezereon {Daphne Mezereum) 2935°. 

 Bed Currant {Ribes rubrum) 3069°. 

 Gooseberry {Ribes Grossularia) 3596°. 

 Alpine Woodbine {Lonicera alpigena) 4164°. 

 Mountain Ash {Sorbus aucuparia) 4339°. 

 Barley {Hordeum vulgare) 4403°. 

 Apricot {Prunus Armeniaca) 4435°. 

 Apple {Pirus Malus) 4730°. 



Barberry {Berberis vulgaris) 4765°. 



Carthusian Pink {Dianthus Carthusianorum)i&li°. 



Elder {Sambucus nigra) 4913°. 



Pear {Pirus communis) 5024°. 



Cornel {Cornus w.as) 5416°. 



Plum {Prunus domestica) blSff. 



Vine ( Vitis vinifera) 5780°. 



Peach {Persica vulgaris) 6004°. 



Horse Chestnut {^Esculus Hippooastanum) 6034°, 



Oak ( Quercus pedunculata) 6236°. 



