1899] Cook, —Additions to flora of Middlesex county 81 
Nasturtium officinale, R. Br., is abundant in a ditch in Concord, 
and it has to be removed in cartloads from a brook in Lexington to 
prevent its blocking the stream and so flooding the meadows. 
The Mustard Family in Lexington has been further augmented by 
Erysimum cheiranthoides, L., Sisymbrium. altissimum, L., *Brassica 
Japonica, Siebold, and B. oleracea, L. Cardamine parvifiora, L. 4 ^ 
hirsuta, L., var. sylvatica of the Flora), was found at Lake Walden. 
Dianthus deltoides, L., is well established in Lexington, and D. 
Armeria, L., given in the Flora as rather scarce, is quite common in 
different spots. 
* Silene Armeria, L., by the roadside, is new. 
Stellaria uliginosa, Murr., was found on the edge of the stream in 
Shaker Glen, and S. ¿orealis, Bigel., is quite abundant in North 
Lexington. 
* Reseda lutea, L., was found in Lexington cemetery. 
Malva moschata, L., and M. Alcea, L., are persistent in fields in 
Lexington. 
The summer of 1898 was peculiar in the presence of species not 
formerly noted. *Geranium pusillum, L., came up abundantly in 
lawns where no new seed had been added. *Valeriana officinalis, L., 
came up in several patches outside the cemetery in Lincoln, and 
*Silybum marianum, Gaertn., in a garden which, in other years, had 
produced Viola cornuta, L., and *Cleome spinosa, Jacq. None of 
these were planted, possibly the seeds were introduced in dressing. 
Oxalis violacea, L., is quite plentiful on Mount Tabor, Lincoln. 
Tephrosia Virginiana, Pers., “not reported in the eastern towns," 
grows in North Lexington. This is a new station also for Genista 
tinctoria, L. : 
Vicia tetrasperma, L., was found sparingly on dumps. 
Poterium Canadense, Benth. & Hook., is sufficiently plentiful in 
Bedford to add a question-mark to the “ scarce " of the Flora. 
Potentilla recta, Willd., reported as scarcely established in Concord, 
has spread from the original station on Monument street to the other 
end of the town, where it has been found in different places in the 
fields of the Concord golf course. 
The naturalization of Zrapa natans, L., in the Concord River is so 
complete that it has become a nuisance and has to be weeded out of 
the Sudbury River above its junction with the Assabet, and far above 
the station where it was planted by Minot Pratt. I wonder that no 
