From Cann River in Victoria to the vicinity of Buladelah in central coastal NSW. I have a plant given to me by Dr Peter Adams of a piece reportedly collected by the late Jim Rantoul from the Cann River district. Rantoul was into his orchids and produced a book on natives. It is thought that var. speciosum no longer exists in the Cann River Catchment. Today its southern limit appears to be in the vicinity of Mallacoota and Genoa, around 30kms south of the NSW border. In Victoria it occurs at quite low altitude, often near salt water, but extending to mossy forest at low altitude behind the coast. In the north of its range it can occur as high as 900 metres altitude.
From the Victoria border it occurs continuously eastwards of the Great Dividing Range, right down to the coast, and northwards to Alum Mountain at Buladelah, which is situated around 200kms north of Sydney. From Buladelah it travels due west to the sandstone country around the Munghorne Gap Region to the north of Mudgee. From the Rylstone district to Munghorne it is actually grows on the western watershed of the Great Divide, one of only three places in the whole length of its range where D. speciosum does so. The other two are var. carnarvonense at Carnarvon Gorge in Central Queensland and var. pedunculatum 3000kms to the north, and just to the west of the Atherton Tableland.
Mature pseudobulbs can be as short as 150mms with only 2 leaves when growing in hostile environs. In high rainfall areas with heaps of leaf litter, pseudobulbs can reach 750mms before the first leaf, with a diameter of 65mms, and nearly round in cross-section. Leaves on these big ones can be 300mms long and 80mms wide. Leaves number up to five usually but rarely there can be six. Occasional plants occurring epiphytically on trees are mostly, but not always, more slender and longer in pseudobulb length. Clumps growing in good conditions can be huge, occasionally as expansive as a family car. Such clumps may be the product of generations of seedlings.
Let me make it clear that I do not intend this to be a lesson in botany. So my terminology will be layman talk. Racemes have short peduncles. The peduncle is the part of the raceme between the leaf axil and the first flower. Mostly the bottom flowers are not clear of the leaves. Racemes can be either short in hungry country without much leaf litter, or very long when all the proper conditions are in place for a happy existence. I have measured one long raceme at 675mms. Longer ones are likely to occur however. There may be up to a hundred flowers on a really long raceme.
Flower size is extremely variable from small, say 30mms, up to 95mms. Anything over 75mms is very rare. These are my personal observations made from actual measurements I have taken. You may have seen bigger ones. Flowers can be very heavily textured and widely opening or thin and not very open. The flowers can be arranged in rows or haphazardly on the raceme, crowded or quite sparsely distributed. They can be pure white, with extremely rare albinos known, through all shades of off white, ivory, bone to cream, to strong yellows. I could keep yapping for ages on the shape etc but I would bore you senseless. You have the gist of it now.
This is the good old form that most growers know oh so well as the NSW Rock Lily. Despite what you may read from time to time, mostly from writers who just repeat parrot fashion what they have heard or read, and who have very little field experience, var. speciosum is quite a common orchid over its range. Sure, there may be the odd fire trail where someone knew a few plants grew, and where those plants have disappeared from. But all in all, if you walk five minutes from the asphalt in suitable country you can still see vast numbers of Rock Lilies about its range. I even know of a big clump on the edge of Middle Harbour in the centre of Sydney nearly.
99% of plants grow on rocks and rock faces and cliffs. The other 1% crop up on trees, mostly in the Illawarra, but other places as well. It is not restricted to sandstone by any means. Any rock substrate will do if the factors var. speciosum demands are present. Aerial roots are virtually unknown but a few clumps I have seen show an inclination to chuck out a few free radicals when growing in a pot.
Flowers can open any time from late August to mid October depending on local conditions. Coastal forms will be earlier then inland forms as a reliable rule. Some years are absolute boom years with vast numbers of racemes everywhere. Other years are complete duds and hardly a flower will be found. These complete dud years are fairly uncommon thank god, perhaps they might pop up every five years or so. Normal years, so I have noticed, mean that perhaps one in every three plants will have a few racemes open up. Boom years mean just that, four out of five plants in a colony will flower off nearly all its pseudobulbs and up to three racemes off a single bulb will be seen.
There are more theories as to why this happens then there is about who was really behind the death of JFK. Some say its to do with the number of hot sunny days versus the number of cloudy, wet or cool days . . . way back near Xmas. Where I live, I start looking out for emerging racemes around mid to late May. By early June I will know if a good year is about to come my way. My flowering is usually at a peak in the second and third weeks of September. Var. speciosum is arguably the nicest form, horticulturally speaking, of all the varieties. Without a doubt the two best-known cultivars are Windermere and National White.