2 PEOFESSOE LINDLEl's CONTEIBUTIONS TO 



herbarium, a specimen has lost a part of its pollen-masses, as is 

 frequently the case with JE. muscicola, DalzelU, &c., its true genus 

 may still be determined. It is mainly because Sarcostoma has the 

 pyriform pollen-masses of an ^ria, although their number is that 

 of Dendrobium, that I now hesitate to reduce it to the latter genus. 



In forming the sections now proposed, it will be seen that a 

 regular sequence of the most nearly allied forms is not wholly ob- 

 tained. However desirable, indeed, such an arrangement may be 

 in theory, it is certainly unattainable in practice in cases where 

 great numbers of species are brought together ; for the points of 

 resemblance and difference are so various and complicated, that, 

 like countries in a geographical map when placed in a continuous 

 series, some must of necessity be dissevered from those to which 

 they are conterminous in nature. Thus the JBolhodia, forming a 

 natural group among each other, run into Stachyobium as much 

 as into Eudendrobium^ next which the section is placed ; and such 

 species as JD. Dalhousieanum are much allied to the Holochrysals. 

 It would, moreover, be desirable to collect into one subdivision 

 such species as D. excisum^ metachilinum, Tmesipteris^ lycojpo- 

 dioides, &c., now forming a part of JEudendrobitim ; but I do not at 

 present see what combining characters are available for the purpose. 



The following Table brings into one view the distinctions of the 

 groups under which the annexed memoranda are collected : — 



Foha verticalia (scalpellifolia) 1. Aporum. 



teretia 2. Strongyle. 



horizontalia. 



Caulis nuUus, rhizoma tantum 3. Rhizobium. 



apice tantum 1-3-phyllus. Folia coriacea... 4. Dendrocoryne. 



a. labello continue. 



b. labello in crinibus solute (Desmotrichum). 

 Gaulis undique fohatus : 



Flores omnino aurei 6. Holochrysa. 



rosei aut candidi, labello tantum quandoque 



luteo. 



MentonuUe 6. Aclinia. 



predu6to : 



Flores fasciculati aut solitarii : 



a. Caule brevissimo, conice {Bolbodium). 



b. Caule elongate /• Eudendrobium. 



Flores dense racemosi, mente elongate 8. Pedilonum. 

 Flores laxe racemesi, mente brevi : 



petalis conformibus 9. Stachyobium. 



petalis elongatis spathulatis 10. Ceratobium. 



