108 BIOLOGICAL SOCIETY OF WASHINGTON. 



563a. Clethra alnifolia, L. White Alder. Sweet Pepper Bush. 



Left bank of Bladensburg mill-race below second foot bridge, 

 200 yards above sluice gate. In flower July 27, 1884, in 

 fruit August 24, 1S84. Prof. Ward. 

 58517. Apocynum androsaemifolium, L. 



Collected near Woodlawn. Fairfax county, Va., August, 1885, 

 by Mr. Wm. Hunter. 



614a. Hydrophyllum Canadense, L. Waterleaf. 



In a ravine containing a cataract which was christened " Hydro- 

 phyllum Run," nearly opposite Eads' Mill, Va.. July 6, 1884, 

 then a little past flowering time. Prof. Ward. Fine flower- 

 ing specimens collected June 21, 1885. 

 620a. Borago officinalis, L. 



Foundry Run, June 23, 1885. Mr. A. L. Schott. 

 675^. Gerardia auriculata, Michx. 



Below Alexandria, Va., Sept. 9, 1885. Mr. Wm. Hunter. 



825«. Comptonia asplenifolia, Ait. Sweet Fern. 



Between the Reform School and Highlands, Md., on an aban- 

 doned earthwork, June 22, 1884, b J Prof. Ward. 



826^7. Betula lenta, L. Cherry, Sweet, or Black Birch. 



Found by Dr. G. W. Hill at the mouth of Difficult Run, Va., 

 May 11, 1884. Dr. Hill states that he could find no full- 

 grown trees, and none bearing fruit or flowers. Mr. Wm. 

 Hunter reports this species from Clifton Station, Va., also 

 as a mere shrub. 

 The following remarkable forms of °>uercus, supposed to be of hybrid 

 origin, are deserving of special mention in the catalogue. Most of them 

 were described by Dr. George Vasey in an article published in the " Bul- 

 letin of the Torrey Botanical Club" for March, 1883, with figures (plates 

 xxviii-xxx). Their principal peculiarities were further pointed out in a 

 paper by Prof. Ward, read before this Society April 13, 1883. 



The names given below are based on the assumption that they are 

 hybrids, the one standing first being that of the species supposed to 

 predominate in the hybridism. 



831^. Quercus alba x obtusiloba. 



Discovered by Dr. Vasey near Silver Spring, Maryland, Sep- 

 tember 20, 1S82. 



