343 



2. Thelymitra truncata, n. sp.. 



Plant slender, about a foot high, with 2 clasping cauline 

 bracts and 2 to 6 blue flowers in the raceme. 



Two segments of the perianth (lateral petals) are spotted. 



Column rather widely winged ; hood with a single yellow 

 glandular lobe in the form of a truncated cone between the 

 penicillate appendages ; upper border of this lobe is horizontal 

 and slightly denticulated ; hair- tufts white, projecting 

 upwards to a level slightly higher than the middle lobe. 



Anther with a well-marked point, lying beneath middle 

 lobe of hood, to which it is adnate. 



Stigma large, somewhat quadrangular in shape, with a 

 depression in upper border, at the base of which is situated 

 the rostellum. 



This plant is sufficiently distinctive not to be easily mis- 

 taken for other members of the genus. Perhaps it 

 most nearly approaches T. longifolia, Forster. In this latter 

 species, however, the lobe of the hood between the hair-tufts 

 is dark-coloured and shortly bilobed or emarginate, whereas 

 it is yellow and truncated in the new species; also in T. 

 longifolia none of the perianth segments are spotted. 



From T. ixioides it is readily distinguished by the fact 

 that it has but a single lobe between the hair-tufts instead 

 of three, as in that species. 



My specimens were collected at Myponga, October 29, 1917 



The specific name refers to the shape of the middle lobe 

 of the hood of the column. 



EXPLANATION OF PLATE XVII. 



1. Thelymitra azurea. 



Fig. 1. Front view of column showing stigmatic surface and 

 rostellum. 



Fig. 2. Side view of column showing the lobes of the hood. 



Fig. 3. A view of the column looking downward from the 

 back showing the posterior (middle) lobe and two adjacent lateral 

 lobes, together with the penicillate appendages. The hair-tufts 

 of the latter are purple in colour. 



Fig. 4. A top view of the column showing the same parts as 

 fig. 3, and illustrating the way in which the middle (posterior) 

 lobe overlaps the two adjacent ones. 



2. Thelymitra truncata. 



Fig. 1. Side view of column showing the single truncated 

 lobe of the hood situated between the penicillate appendages. The 

 dotted portion is yellow in colour, and the superior margin of the 

 lobe is slightly denticulated. 



Fig. 2. A front view of the column showing the stigmatic 

 surface and rostellum, above which is seen a portion of the anther. 



Fig. 3. A top view of the hood of the column showing the 

 truncated yellow (dotted) lobe between the penicillate appendages. 

 The tip' of the anther is seen projecting within the horseshoe 

 formed by the upper margin of this lobe. Hair-tufts are white. 



