108 DR. HOOKER AND DR. THOMSON'S PRECURSORES 
folie we suspect that it is spurred or muticous in the same spe- 
cies, though, in the present condition of synonymy, we have often 
been obliged to accept such modifications as of specific value. The 
spur itself may be straight or curved or spiral, ascending or de- 
scending (according to the position of the flower), attenuate or 
inflated, or clavate or saccate, being sometimes variable in these 
respects in the same species. 
6. The lateral sepals may be two or four, the two posticous alone 
(those next the labellum) being invariably present and tolerably 
constant in form ; the two anticous, first observed by Edgeworth, 
may be present or absent in the same species, and are often reduced 
io papille or glands. The apices of the sepals (as of the dorsal 
spur of the vexillum) are often glandular. The relative size of the 
sepals and petals offers too often a very fallacious character, de- 
pending primarily on conditions of flowering. 
7. The form of the flower may be flat—that is, with the laminz 
of the vexillum, ale, and even of the labellum, all in the same 
plane; or the whole flower may be concave, from the concavity and 
prominence of the vexillum and labellum especially, which (as in 
Т. macrophylla) may greatly exceed the alæ, and, appearing to con- 
fine these, give them a vertical direction. 
8. The colour of the flower is very variable in many of the 
species ; yellow and purple are the prevailing colours, the former 
passing through ochreous, &c., into a dull red, and the latter 
through pink, &c., into white. In many, the flowers are spotted, 
the yellow with various shades of red or purple, and the purple 
with darker spots or blotches. In I. racemosa and its allies, the 
yellow and pale purple are mixed, and we find the same species 
with wholly yellow and with dirty purple flowers. For extreme 
variation of colour in one species, we would cite I. longicornu and 
leptoceras ; for intensity of colour, Г. janthina and racemulosa. 
9. The inflorescence is always lateral, though apparently terminal 
in the Scapigere and in some of the Racemose. The peduncle is 
solitary in many, fascicled and axillary in most of the Lateriflore. 
The peduncles are 1-flowered in some, 2- or many-flowered 
in others; solitary in some, and fascicled in others. "The species 
with normally fascicled 1-flowered peduncles have sometimes the 
fascicles reduced to one peduncle; and the species with 2- or more- 
flowered fascicled peduncles present sometimes 1-Йожегей fas- 
cicled peduncles, or even solitary 1-flowered peduncles. This leads 
to great confusion and an inosculation of some species (or indivi- 
duals) in all the groups with alternate leaves, which we have been 
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