^ Hhodora [January 



solutoly essential to know what l*iirsli had descrihed as Orchi.s- orhi- 

 cuhifa. Aecordiiifj to Pursh's P'lora Ainericae Septentrioiialis, llabc- 

 varla orhinilafa irduihits the mountains of Pennsylvania and Mrginia 

 and blooms in July and August. Our ])resent knowledge of the dis- 

 tribution of the sj)eeies as far as the short-spurred form is concerned, 

 extends this range to Canada and Alaska in the north, and to Mimiesota 

 in the middle west. The long-spurred form is rather rare and as rep- 

 resented in the princi[)al herbaria of the United States does not reach 

 so far south as Pennsylvania and Virginia and does not occur west of 

 Wisconsin. Therefore, tlie evidence su|)[)licd by distribution would 

 make it .seem that the Pursh plant nuist have been characterized by 

 a short spur. According to Pursh's Journal of a botanical Excursion 

 in the Xortheastern part of the States of Pennsylvania and New York 

 during the Year 1S()7, he found a Ilabenaria late in June in Penn- 

 sylvania, which he called Orclii.s- bifo/la because of its resemblance 

 to the European species so called in his time. He gave an elaborate 

 account of it and his description agrees well with the character of //. 

 orbiculafa, although it doi-s not distinguish his material from the long- 

 spurred form which (Joldie called //. inarrop/ii/lla. Tnt'ortunately 

 Pursh's herbarium is no longer intact as it was distributetl at the sale 

 of the Lambert collection of which it formed a part; but in my search 

 for an authentic s{)eciiuen 1 found at Kew a sheet which I think nuiy 

 be accepted as the ty])e of his Orr/ii.s orhinilafa. It is a sheet from 

 his own herbarium and was presumably accpiircd for Dr. Hooker at 

 the Land)ert sale. The s|)ur, which is 2 cm. long, distinguishes the 

 plant at once from //. marrophyUa, (Joldie, and establishes the identity 

 of Platanfhera Mrrizlr.'iii, Lindley, which we must regard as cons])ecifie 

 with the Pursh j)lant. 



Whil(> on the jireceding j)agcs Ilabenaria orbiculafa and //. macro- 

 phjllla have been separated by the length of the spur, the two species 

 are readily distinguishable by other differential characters. That 

 the spur length, however, is the most uscfnl diagnostic character can- 

 not be denied. It is not an arbitrary distinction and does not lead 

 to artificial discrimination among specimens, irrespective of distribu- 

 tion and habitat. Th(> diagnostic value of the spur is clearly shown 

 by the following tabulation of length-frequencies.^ 



'The sniirs of Platanthcra Mcnziesii are not included in the meiisurenieiit.s as Lindley's 

 t,vi)e iirui the Uritish Museuin specimens collecte<I by Menzies are not fidly develojjed" 



