I lit Mt'cliutiism ol Self-pollination 



Prssccliori ot buds and finished 

 gofers piovidcd the complete picture 

 „f the mechanism adopted by this 

 oichid. !l hs$ been previously pub- 

 lished In Rogers' hm as this 

 pflpff rnay he unobtainable lor some 

 | redeserihe the mechanism here 



In Ihe very early hud the column 

 appendages and anther are erect, 

 jhc .miner appeals enormous and 

 (ru kes up Ihe hulk ol' the column. 

 1 he !UttlWr-Sa« are completely closed 

 -ml dissection shows the pollinia to 

 tv tet\ pale und coherent. I he 

 COltflWl appendages are only slightly 

 called and also pale al this very 

 early stage Ihe stigma is small', 

 -icon, round and moist 



hi the hud ahout five days belore 

 upcning a nujnbcr of changes arc 

 obvious. The tip of ihe aittliei lias 

 moved down and is now almost at 

 nylM angles to (he rest of ihe column, 

 i In some buds al this stage the Up 

 of the column is still al about 60 ). 

 I he polluiia are pale but are begin- 

 ning to appear Inahle. In odd 

 flowers a polhnium will be found 

 jlicad> on the stigma but in Ihe 

 majority the anlher sacs have not 

 ••fciicd sufficiently The stigma has 

 enlarged and the column no longer 

 jppears to be composed cntirelv of 

 Ihe anlher as in the early buds. 



Two to three days befoie opening 

 Ihe anllier sacs are quite wide and 

 ihe majority ol flowers have pollen 

 on then »him>as. At this stage Ihe 

 *tipn*\ Ate fully developed and 

 odiously very sticky. The pollinia 

 i -u lost nU'Ch of thcii coheicncc 

 and individual grunts arc cisilv seen 

 I In approximately ICS of the buds 

 'it this Mage, the anther sicv weie 

 Mitl closed). 



Self-pollination has taken place in 

 the majority of (lowers by the lime 

 they have opened. 



In the expanded Mower Ihe anther 

 sacs arc wide open and almost hori- 

 zontal. The majority of pollinia have 

 lallcn from them and are adhering 

 to the vestigial rostellum ami the 

 stigmatic surface. Under the lens Ihe 

 siigm.. .ippcars glistening ami gluey 

 with the surface becoming distorted 

 Ihe pollmt,. appear lo be dissolving 

 wheie they are touching the glue. 



The stigma of the withered flower 

 is verv swollen and distorted and the 

 remains of pollinia are barely dis- 

 cernible. The anther sacs tire brown- 

 ing and curling up at the edges. 

 Occasional pollinia will be found 

 adhering to a sac but Ihese have lost 

 all coherence and are merely a 

 Huffy mass of pollen graius. 



Summarizing the procedure shows 

 how simple is Ihe overall piocess. 

 I he downward movement of the 

 column brings the pollinia into a 

 direct line above the stigma. The 

 opening of the anther sacs < possibly 

 also brought about by the downward 

 movement of the column) allows the 

 pollinia to siniplv drop onto the 

 stigma — a process probably facili- 

 tated by movements of the tlower 

 stem in the wind. 



LmiMHHi CrrtD 



1 Rueers. R. S. Mechanism of Polli- 

 nution in certain Australian Orchids. 

 Tram. roy. .Sot. S..4. 37: as (1913). 



2 Nicholls. W H , Orchids nf Am- 

 Haiti I Plate 49 (1955). 



) FtMnORi J M . 'he t.iscination of 

 ouin.K laltohe \allcv Naturalist 

 No 75 I March 1 971)). 



! \,|.h, K. C« Vhtic intcrcsline cor- 



rtspiindeiitc. The Qrc/rmfAM 3: 37 



Au9usl. 1971 



vi i 



