Howe: American Species of Alectoria 115 



man herbarium, though a more reduced form is also discovered, 

 i. e.j stygiodes, not mentioned in Mr. Merrill's paper. I have also 

 examined the Eckfeldt topotype in the Academy of Natural Sci- 

 ences at Philadelphia, and with it the specimen sent Dr. Eckfeldt 

 by Mr. Merrill for comparison. 



If we are to consider this plant an Alectoria, as the genus has 

 been commonly understood, we must find the branches structur- 

 ally cylindrical (= terete), compressed at the axils or along the 

 larger branches; the apothecia lateral, rarely appendiculate (when 

 borne on the short undeveloped branches of oregana), generally 

 innate-marginate, margins entire, at length suppressed or fimbri- 

 ate (oregana); the medulla stupose, arachnoid or wanting; the 

 spermogones and spermatia are hardly diagnostic enough for 

 serious consideration among the genera of Usneaceae and 

 Cetraria. 



I cannot admit of the above diagnostic characters for the plant 

 under consideration though for the most part they are applicable 

 in a loose way. The branches are not truly* cylindrical, the 

 apothecia occasionally appendiculate, the medulla is distinctly 

 dense. If the idea of radial structure is made to include such 

 plants as the one we are considering, we must allow ourselves 

 besides, almost unlimited latitude as to the position of apothecia, 

 even if we waive the margination as in any way diagnostic. The 

 margins within a genus are of course admittedly variable, — the 

 genus Evernia has its pseudo-ciliate member in vulpina; Alectoria 

 in oregana, and the ciliate species of Usnea an almost eciliate 

 member in trichodea. 



Mr. Merrill has remarked on the similarity between calif omica 

 and the thicker, shorter, undeveloped branches of oregana, and 

 in a comparison of the short, caespitose branches of the latter 

 plant with calif omica it is admitted a similarity will be noticed. 

 It would seem therefore that the filamentous portions of oregana 

 bridge the transitional gap between the pendulous species, and a 

 fertile caespitose condition seen in part in Alectoria oregana. As 

 already has been said, and what is also true of the Usneas, the 

 caespitose plants are more commonly fertile, and this is true of 



* Due to frequency of fistulas, the circular distribution of gonidia is rarely 

 co: -plete. 



