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Roraima 2


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Orchids grow everywhere and almost all of them are perpetually in flower. There are representatives of several genera, in a range of sizes from the microscopic Trichosalpynx (Pleurothallus) roraimensis to the tall and often bonsai tree-like Epidendron dendrobioides.

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Epidendron dendrobioides

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A few different bromeliad species are present on the summit. The air plant Tillandsia turneri can be found growing epiphytically on trees, terrestrially amongst grasses and lithophytically on bare rock.

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More common than B. reducta, Brocchinia tatei grows to quite a size and is often seen with an invasion of Utricularia humboldtii in its rosette.

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Here is Ch’ien Lee standing next to a large Brocchinia tatei. As all bromeliads die after flowering, this one has obviously never done so and is so old it has formed a trunk.

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There is very little forest on the summit plateau but in just a couple of sheltered areas short but dense cloud forest can be seen.

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One particular and infrequent plant I fell in love with and only found in these small patches of cloud forest was a small tree fern of the genus Blechnum. At first I thought this plant was a cycad and it was only after finding spore-producing, fertile fronds that I was sure it was a fern.

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In sheltered, shady spots close to running water the delicate, lacy fronds of Filmy Ferns were found. These ferns need almost 100% humidity to keep their very thin, transparent leaves turgid.

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This is a common little fern (I believe it is an Elaphoglossum sp.), which does a great job in mimicking Utricularia quelchii. Here it is actually growing with U. quelchii. (Can you spot the difference?)

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Edited by An D Smith
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Hello Andy,

Thanks for posting your beautifull photographs! This brings back some impressing meomories of the fantastic trip, and reminds me of tons of photos that I wanted to show here ;)

I especially enjoyed your fern photographs!

The cycad-mimic Blechnum we found on Roraima is Blechnum schomburgkii, and your photographs seem to be among the first colour images available for this species.

The Utricularia-quelchii-mimic fern with the rounded leaves is not an Elaphoglossum, but belongs to the distinct fern family Pteridaceae (at least currently ;)). It is a member of the genus Pterozonium, which is almost exclusively endemic to the tepui summits of the Guayana shield, comprising 14 species all which look very similar (rounded spatulate to obovate lamina). However the species we found on Roraima summit, Pterozonium cyclophyllum, is rather easy to distinguish as it has linear sori on the leaf lower surface. I'm not quite sure if you took your photos of the same individual, however all Pterozonium ferns I observed had stripes of sporangia, not just patches concentrated on the margin of the leaf.

Daniel, the leaves of the fern can be distinguished by the fine veins on the upper leaf surface, whereas the leaves of U. quelchii are always smooth. Moreover, at least in Andy's photograph, the Utricularia leaves have a more acute apex, compared to the rounded leaves of Pterozonium.

All the best,

Andreas

PS: The tepui orchid Epidendrum dendrobioides recently had been splitt into several species (which orchid was not, haha? ;)), and our Roraima plant shall now be called Epidendrum ulei.

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Andreas

You are a veritable mine of information and I thank you for sharing your wealth of knowledge on the plants of this area. I can now finally put a name to some more photos.

I could almost have guessed that the orchid name would have changed!

Cheers

Andy

Edited by An D Smith
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