2a; 
Flowers in natural position either urceolate or ventricose, 
i.e., the three sepals highly connate with one another form- 
ing an inflated base ........ SUBGENUS DIALISSA 
Flowers in natural position either bilabiate, 1.e., lateral 
sepals forming a variously connate synsepal, or stellate, 1.e. 
all three sepals free, together forming a triangle in outline 
Ee eee re ee ne ne ene eT ee ee 3 
Flowers stellate; sepals either radially or bilaterally symmet- 
TCA. aca haewecy scene ees SUBGENUS STELLATA 
A. Column with a prominent foot SECTION PEDALES 
AA. COMM ACOUCES. cccadisnend 448 bees bese teas B 
B. Disc of lip either with a protruding transverse ridge or 
convex, cushion-like ..............cccccceees Cc 
BB. Disc of lip either flat to concave or deeply excavate 
ee Te ee er ee ee ee F 
C. Lip viewed from side commonly triangular to repli- 
cate-triangular in outline; disc viewed either from 
above or from front, always with a well-defined, 
fANISVEISe TICE: 2 hate eas SECTION DISTICHAE 
a. Bracts well-developed, longer than pedicellate 
ovary, often distichous, and/or imbricating 
eatwewt cua ceed others 1. S. disticha alliance 
aa. Bracts small to inconspicuous ........... b 
b. Column elongate, much surpassing the petals in 
IGNOU 4.05 bs 7% bs4es 2. S. columnaris alliance 
bb. Column short, as long as, or shorter than petals 
c. Sepals form an equilateral triangle in outline 
(ieee ae ee eens 3. S. purpurascens alliance 
cc. Sepals form an inequilateral triangle in outline 
(ei GhAReP HG LOE Re eRe 4. S. elatior alliance 
CC. Lip viewed from side never triangular in outline; disc 
cushion-like without a well-defined, transverse ridge 
D. Lip longer than wide .... SECTION RHOMBOIDEAE 
a. Lip ovate-rhombic in outline, widest near base 
ee ee ere re 5. S. rhomboidea alliance 
176 
