Mackenzie: Notes on CarEXx—XII 369 
When I prepared the article on Carex for the second edition 
of Britton & Brown’s Illustrated Flora, I treated these two 
plants together, because the number of heads and their degree 
of separation was not a constant character. Later, in a paper on 
Carex straminea and its allies (Bull. Torrey Club 42: 603. 1916), 
it was pointed out that the genuine Carex festucacea was a differ- 
ent plant than either of the above, and the name Carex brevior 
(Dewey) Mackenzie was applied to what I had treated as Carex 
festucacea Schk. in the Illustrated Flora. 
In the meantime Kiikenthal (Pflanzenreich 4°: 207), notic- 
ing the close general resemblance of Fernald’s Carex festucacea 
to Carex Bicknellit Britton (Carex straminea var. Crawei 
Boott), cited it under his treatment of that plant. 
A detailed study has disclosed that the large northern plant 
here under discussion has characters which are constant in a 
very considerable series of specimens. As compared with Carex 
brevior it has the perigynia appressed-erect instead of spreading- 
ascending. The mature perigynia are membranaceous and 
strongly pellucid-puncticulate. They entirely lack the firm 
coriaceous texture so characteristic of Carex brevior and are 
also more nerved than in that species. These differences are 
well brought out in Fernald’s figures above referred to, even 
the difference in the texture of the perigynia coming out. 
The culms of the northern plant are much developed the 
first year of their growth, and the old dried leaves towards the 
base of the culm are therefore very marked in the flowering year. 
In Carex brevior on the other hand the development the first 
year is much less, and the dried leaves are short and rather 
inconspicuous in the flowering year. The sheaths too in the 
northern plant are white-hyaline ventrally for but a short 
distance, while in Carex brevior this feature is very strongly 
developed, and they also differ from those of the latter plant in 
being strongly papillate dorsally. As stated by Fernald the 
northern plant has five to ten spikes which normally are distinct 
and well separate, and Carex brevior usually has fewer spikes 
which are approximate or sub-approximate. However, this is 
but a well-marked tendency and specimens of the northern 
plant with a congested head or Carex brevior with spikes as 
widely separated as in the northern plant are not uncommon. 
Carex Bicknellii can be readily distinguished by its larger 
