257 



THE BlUTISH PALMATE ORCHIDS. 



Br Hey. T. Stephensox, D.D., a^s'd T. A. Steimienson, M.Sc. 



(Platk 5o(j.) 



The 2)resent contribution is offered as a suinniarj of the result 

 of several years' work on the Marsh and S[)otted Orchids, and to 

 explain the accompanying Plate. We hope to amplify it in the case 

 of some of the forms in later issues. 



The decision resulting from our work is that, although the forms 

 in question run into each other very much, they are not a hopeless 

 tangle, and it is quite possible to recognize certain definite Jioichiiarks 

 or species among the mass of forms, and to detect many intermediate 

 J///hri</s. This does not controvert the fact that a series of inter- 

 mediates between some of the species is found, but a little careful 

 study reveals very definite types. 



According to our idea the British Palmate Orchids comprise the 

 six following species: — 0. uicantafa L., O. i^urpurella Stephenson, 

 O. ericetoriim Linton, O. pratermissa Druce, O. latlfolia L., 

 O. Fnchsii Druce *. 



O. iNCAiiNATA can always be clearly recognized from its .sword- 

 like, never-spotted leaves and its unusualh" small flowers with veiy^ 

 stout spur, stiffly erect sepals, and lip as a rule longer than wide, 

 reliexed, not deeply lobed, and with a pattern almost always composed 

 of definite lines inside a single more or less continuous enclosing 

 boundary-line. The exact form of lip and leaf is variable, but the 

 whole plant is immistakeable. The flower may be white, ))ale yellow, 

 })ink and yellow, mahogany-red, deep crimson, rose-pink, light or 

 dark pur])le. The habit is dwarf or tall, the leaves are bi'oad or 

 narrow. 



O. pj^.etehmissa has been a good deal criticized, but it is. in our 

 opinion, a perfectly good species, and cannot be confused with 

 O. TXCAKNATA. The flowcr is always purple or crimson-pur[)le of 

 some shade, lilac, or white. The lip is typically broader, flatter, and 

 larger than in O. incartiafa, and in the type-forms has a less definite 

 and strong pattern, often of small dots, and a somewhat less stout spur. 

 There is, however, a form common in the. north more particularly. In 

 which the flower-colour is red crimson-purple, the lip-pattern heavier, 

 and the lip may be somewhat diamond-shaped — this is a very distinct 

 form, and there seems to be a somewhat similar variety distinguish- 

 able in O. incarnafa, the v. pulchella of Druce (see J. B. 1920, 

 p. 16G). The leaves are never spotted in O. prcetermissa, and are 

 less sword-like than in O. incarnata. This species is evidently con- 

 sidered by some botanists to be typical O. lafifolia, but to that we 

 will refer later. 



* We use the names ericetorum and Ftichsii rather than ericetonnn and 

 maculata simply to avoid confusion, because different botanists will take the 

 word "mac nlafct" to mean quite different things. We prefer to use the name 

 macnlata as a general terra of reference to both, an ag-grogate species-name. 

 We will refer to this later in more detail. 



JouitXAL OF BoTAXi'.— Vol. 58. [Novemi3E1{, 1920.] x 



