112 DR. HOOKER AKD DR. THOMSON'S PR^CURSORES 



"We add a key to the species, arranged under their countries, 

 but have little confidence in its proving a certain guide to 

 determining them systematically, — our object in this, as with the 

 other Prsecursores, being to bring together all the available matter 

 regarding each genus, rather than to present it in a completely 

 elaborated systematic form*. 



CONSPECTUS SECTIONUM. 



A. ScAPiGER^. JRMzoma breve, perenne. Folia omnia radicalia. 



Scapus gracilis, apice racemifer. — {JBractecB patentes pedi- 

 cellis multo breviores, carnosulse. Fedicelli graciles. Sepala 

 latiuscula. Labellum saccatum v. calcaratum. Alee 2-3-lob8&. 

 Vexillum fomicatum. Capsula late elliptico-oblonga v. lan- 

 ceolata. Semina pustulata, minima.) (Sp. 1-5.) 

 A perfectly natural group, and readily recognized, confined to 

 the western peninsula and Ceylon. 



B. Oppositifoli^. Annuae. Folia omnia opposita v. in paucis 



alia opposita, alia ternatim verticillata. Fedicelli solitarii v. 

 fasciculati, uniflores, rarissime (in I. salicifolia) 2-flores. — 

 {Sepala angusta, labello plerisque concavo calcarato v. mutico, 

 rarissime saccato. Vexillum ssepius breve. Alee non caudatse. 

 (7<^5?^Zabrevis, medio turgida, utrinque attenuata, in I. Kleinii 

 solum subcylindrica et I. salicifolia clavata. Semina magna, 

 testa laevissima.) (Sp. 6-20.) 

 For the most part a very natural group. I. salicifolia is the 

 chief exception, its 2-flowered states being referable to D. Many 

 of the species are very doubtful, and the synonymy is confused, 

 the original specimens being in many cases bad, or badly named 

 in Herbaria. The I. pendula and Mysorensis, though alternate- 

 leaved, should naturally come into this group; and single-flowered, 

 opposite-leaved specimens of lej^topoda ?, radicans, and others of C 

 may be referred to it. 



C. Stjbyerticillat^. Folia omnia subopposita, v. inferiora al- 



terna, superiora opposita v. verticillata. Fedunculi l-oo -flores. 

 (Sp. 21-33.) 

 A very artificial group, divisible into those with one-, and those 

 with two- or more-flowered peduncles. Occasional specimens of 



* Whilst these pages were passing through the press, a Number of the 

 'Madras Journal of Science' (Sept. 1858) has been announced, contahiing an 

 important paper by Lieut. Beddome on the Peninsular species, to which I 

 shall refer at the end of this monograph. — J. D. H., Kew, Nov. 10th, 1859. 



