Nov,, 1904.] Leaf Expansion of Trees and Shrubs. 
2 1 1 
the 14th of May. A period of fifteen days, therefore, intervened 
between the leafing of the first individuals and the last. In such 
cases the period marked was the time when the leaves were 
appearing rather commonly rather than the first individuals. 
The willows showed interesting peculiarities. Some species 
appear very early, others quite late. If this is the usual course, 
the time of leafing might be of some value in determining species 
in early spring. Some of the maples and buckeyes are the most 
sudden in the unfolding of their leaves. The catalpas, coffee- 
bean, fringe-tree, and hop-tree develop the foliage very slowly. 
It was also observed that many trees begin to leaf at the top. 
Syringa vulgaris L. 
April 1. 
April 2. 
Larix laricina (Du R.) Koch., L. decidua Mill., Salix babylonica L. 
April 5. 
Salix fragilis L., Lonicera tartarica L., L. korolkowi Stapf. 
.4 pril 7. 
Salix alba L. 
A pril 8. 
Prunus serotina Ehrh. 
April 11. 
Euonyraus atropurpureus Jacq., E. europaeus L., Ribes aureum 
Pursh., Cydonia japonica Pers., Sambucus canadensis L. 
April 14. 
Euonymus obovatus Nutt., Spiraea hypericifolia DC. 
April IG. 
Rubus occidentalis L., Prunus virginiana L. 
April 18. 
Aesculus glabra Willd. 
April 21. 
Philadelphus coronarius L. 
April 23. 
Betula alba L., Sorbus aucuparia L., Symphoricarpos racemosus Mx., 
S. symphoricarpos (L.) MacM. 
April 25. 
Staphylea trifoliata L. , Acer negundo L., Cornus baileyi Coult. and 
Ev., Ligustrum vulgare L., Viburnum opulus L. 
April 26. 
Berberis vulgaris L., Rosa rubiginosa L., Malus malus (L.) Britt., 
Prunus japonica Thunb., Comus alba L. 
