The Portuguese Sundew Part 3
Kamil Pasek, Czech Exotic Plant Society
The Portuguese Sundew (Drosophyllum lusitanicum Link.) in nature and cultivationJan Flísek & Kamil Pásek
At 13:10 we said goodbye to this location and to the Drosophyllum. We started the almost 700-km long journey through streamless, but magnificent Spanish lands from the town of Cordoba to Madrid, and eventually to the locality of Pinguicula dertosensis. The sight of Drosophyllum lusitanicum in its native habitat was imprinted so firmly in our minds, that we would certainly have to return here again!
Common comments from our observations at Drosophyllum localities
Previously described localities are likely the most eastern ones in regions where Drosophyllum occurs. Drosophyllum grows in acid sand-loamy soil, in the sandstone clefts and cracks, in sandstone-loamy gravel and in pure sand. A sample of the more loamy than sandy soil from the superficial layer at the locality near Ubrique had a pH of 5.3. The plants prefer full sunlight and eroded places without any cover. Growth of the plants in the underbrush of shrubs and grasses is poor. Plants never grow in the shade of the oak woods. The plants can survive high temperatures for a long time (even 45°C) or light frosts (down to -7°C in cultivation) without any damage. Literature differs in what are the typical altitudes of incidence for Drosophyllum. Although some authors cites that the plants grow from sea level to 400m a.s.l. or lower, we observed Drosophyllum growing at altitudes up to 750-800m a.s.l..
Dewy plants always had a lot of prey. The rosette of leaves reached 15-25 cm in diameter. One rosette typically had 1-5 flower stems and 5-7 flowers per stem. One follicle contains 7 - 10 seeds. There were many young seedlings and old plants at the localities. The older plants branched approximately 4-5 times.
The growing range of Drosophyllum is limited to maritime regions with characteristic regular morning fogs bringing essential moisture in the summer periods, when no rain falls for several weeks. The surface of the soil was absolutely dry during our visit. When we had returned back via the inland region of Spain, we drove through the nearest adjoining mountains, Sierra de Grazalema, comprised primarily of limestone. There were no Drosophyllum there at all, although clouds from the Mediterranean Sea and Atlantic Ocean gathered in this area- in a few ridges high above 1000 a.s.l. of the mountains Sierra de Grazalema with the highest top Torreone (1654 m a.s.l.). Despite a lot of rain falls in these limestone mountains, the incidence of Drosophyllum has not been recorded there. May be the reason is that the plants do not grow in alkaline soils.
And why does Drosophyllum not grow further inland? As discussed above, Drosophyllum gathers moisture from regular morning fogs typical for the maritime regions. These morning fogs usually dissipate near the coast, generally between the first mountain ridges (as in the case of Sierra de Grazalema) and the coast. Hence, areas further inland from these mountain ranges are essentially fog-less. This lack of a regular source of water in summer is the reason why Drosophyllum does not grow in the dry central regions of Spain.
And one last interesting observation of Drosophyllum in its natural habitat. Our plants are grown in open outdoors-garden cultivation from spring to autumn. It is interesting to note that plants in the garden capture more ins