Anyway, early in 1997 Len put his problem on Brom-l and got some interesting replies.
Eric Gouda from Holland pointed out that in his experience both T. albertiana and T. argentina were spasmodic flowerers in cultivation and that he has yet to be convinced that T. dorotheae was, in fact, a hybrid.
Walter Till from Austria, who believes that T. dorotheae is a hybrid pointed out that in his experience the flowers of T. dorotheae do not open, or if they do, only imperfectly. This disturbed flowering could explain the flowering period being independent from its parents.
This fascinating problem may never be solved because there are so many unknown factors but this should not stop us discussing it.
In my experience both T. albertiana and T. argentina are spasmodic flowerers with T. dorotheae being quite regular AND later. But a recent acquisition of another clone of T. argentina has this flowering the latest of all! I have found that flower buds on many Tillandsias will abort or set seed cleistogamously if the day temperature is higher (or is it lower humidity?) than they seem to have been used to in the wild. There appears to be an inbuilt mechanism which stops the plant wasting energy in producing flowers under less than optimum conditions. Even so, T. dorotheae has no difficulty in fully flowering in Adelaide conditions with lots of pollen. I am not sure of its potency and wonder whether the technique used by Gardner (Refer Selbyana August 1984) is still an accepted practice to denote the possibility of hybrid origin.
The flowering period of cultivated plants is often printed in various newsletters and is part of a current Internet project but to me has little value. The relative time in hours after sunrise plus prevailing temperature would seem more important.
In the wild all plants grow from seed to maturity so all would be subjected to the same time clock of atmospheric variables. The same species can have a range of habitats and one would expect plants in the lower regions to flower earlier than those from higher elevations. I do not know if this biological clock is genetic or triggered by atmospheric conditions or a bit of both. For example a plant whose flowers open at dawn and close by midday would rarely hybridise with a plant, even close by, that flowers in the afternoon. So it is refreshing to see statistics such as that on the Web page for Ludwig Buckup at BROMELIÁRIO CAIRÉ. He must be encouraged to continue with this work on the endemic genera and perhaps extend his findings to include time of day etc.
This area is of particular interest to Peter Franklin of New South Wales and myself in South Australia and some 1000 miles apart on this Island of ours. Both of us are interested in Ortgiesia, a sub-genus of Aechmea. We find so many man-made hybrids in this group that are baffling. Many of the acknowledged species could easily be hybrids from within the same sub-genus from the characteristics they show. Hybridisation in the wild can only occur if flowering occurs in the same time frame of plants within pollinator range. Little is reported on this factor. In fact Peter was quite excited to find that Aechmea kleinii was night-flowering according to Smith and Downs. By the way, both Peter and I are strongly of the opinion that this species should be treated in the Ortgiesia sub-genus not Pothuava. However, on further investigation Peter found that the original description mentioned flowers opening at midnight and remaining open to midday next day. Hardly nocturnal!
In cultivation most plants are offsets, not seedlings, and flowering seems to be linked to when an offset was removed, when it rooted, how big it was on removal, as well as atmospheric variables and fertiliser used! Therefore one must be careful in comparing cultivated times with wild times.
In an attempt to address this particular problem I spoke to a person who had recently collected in the type locality for Tillandsia albertiana and yes, T albertiana and T. argentina were in flower at the same time. Where was T. dorotheae? Either not there or not in flower! After discussing the problem it was evident that our intrepid explorer had been unaware of the existence of this slightly different plant. Perhaps when he next visits this area he will restrict himself to photographs so I can see for myself.
On the face of it I would tend to agree with Eric Gouda and say T. dorotheae is an intermediate species or at least on its way to becoming one. Clearly, if it doesn't flower with either of its parents it cannot back-cross and be brought back to the fold.
Have you any comment? Have you any alleged natural hybrids in your collection that flower at different times to BOTH of the parents? Please drop Uncle Derek a line or two.
If you want to check up on putative natural hybrids the only comprehensive list I am aware of is in the catalogue of Bird Rock Tropicals. Here Tillandsias prevail but then this is the genus where most natural hybrids are reported. To my mind this is because Tillandsias seem to be collected or owned by specialists and therefore are reported on more than other genera
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