Fernando Rivadavia Posted June 18, 2014 Report Share Posted June 18, 2014 (edited) Hello everyone, Here is another call to correct your plant labels! :) A few colleagues and I have just published a 35-page review of the D. montana complex. Like our previous publications on Brazilian sundews, this paper has been decades in the making and it has definitely been the most “complex” of all the sundew complexes in Brazil, at least in historical terms. Since D. montana and D. tomentosa were originally published by Saint-Hilaire nearly 200 years ago, there have been endless cycles of synonimizations and of lumping with unrelated species – culminating with the absurd Flora Neotropica in 2005, where ten names were lazily lumped under D. montana. In our new circumscription of the D. montana complex, we have left only D. montana, D. tomentosa var. tomentosa, D. tomentosa var. glabrata, D. tentaculata, and a new (& narrow endemic) species D. spirocalyx. This is supported by characters such as leaf shape & vernation, chromosome numbers, and molecular phylogenetic data. Excluded from the D. montana complex (hopefully permanently) are the following taxa: D. hirtella var. hirtella, D. hirtella var. lutescens, D. schwackei Rivadavia, D. parvifolia Saint-Hilaire (= D. communis), D. cayennensis Sagot ex Diels (including D. pumilla Santos, D. colombiana Fernández, D. panamensis, and D. sanariapoana Steyermark as synonyms), D. montana f. parviflora Chodat (= D. communis), and of course D. roraimae (Klotzsch ex Diels) Maguire & Laudon. Hopefully our new publication will set the record straight for a long while with the D. montana complex! Anyway, see below some pics and extra info for each taxon. First we have D. montana, which is the most widespread in the complex. Through herbarium specimens, we’ve newly discovered that this species is very common on the eastern slopes of the Andes in Bolivia, and possibly also extends into Peru and Argentina. Maybe as a result of this huge geography, it is probably not surprising that it is also somewhat diverse morphologically. However we were not able to establish clear-cut morphological lines, and thus opted to describe 3 morphotypes: Typical, Southern, and Central-western morphotypes. The characters that distinguish D. montana include the fact that it tends to go completely dormant in the dry season, it flowers in the summer, does not form stems with age, has uniformly-sized glandular trichomes from base to apex of the scapes, long and broad ovate to oblong-ovate sepals, and has relatively delicate leaves that are oblong, oblong-spatulate or more rarely spatulate. Here are two pics of D. montana rosettes where you can see the narrow leaves: And two pics showing the highly glandular scapes of D. montana (pics by Nilber Silva): Then we have another widespread and very abundant species: D. tomentosa, distinguished from other taxa by its obovate to oblong-obovate leaves (rarely oblong), with wide petioles (0.4–3 mm in width). It also shows some morphological variation across the range. Variations in density of the eglandular hairs on scapes seems to support the original description by Saint-Hilaire, splitting D. tomentosa into two varieties: D. tomentosa var. tomentosa with hairy scapes and D. tomentosa var. glabrata with glabrous to subglabrous scapes. We decided to keep these two infraspecific taxa at the varietal rank, due to the huge overlap in their geographical ranges, possible hybridization, and the fact that the sole distinguishing character (scape eglandular indumentum) is not easily quantifiable. Here's a typical dense colony of D. tomentosa at a seepage: Here's a view of a D. tomentosa rosette with typical broad leaves. Notice the scapes are practically hairless, meaning this is D. tomentosa var. glabrata: Here are two pics of D. tomentosa var. glabrata, with its mostly hairless scapes (glandular only): Here are a few pics of D. tomentosa var. tomentosa with its ultra-hairy scapes: So why did we keep two taxa as variaties of D.tomentosa instead of at higher rank (or none)? Even though the extremes are often found growing in the same habitats with no intermediates. However hybrids are known and there are numerous populations somewhat intermediate in regards to scape hairyness. Thus, we followed Saint-Hilaire and kept varietal rank due to the difficulty in quantifying this character, until further evidence is presented. Here's a plant we classified as var.tomentosa, since hairs were found all the way up the scape, even if less dense than the ones above (pics by Nilber Silva): And just as a reminder, D. tomentosa (both varieties) are known to freely form hybrids with D. grantsaui almost everywhere they meet, the hybrid being known as D.X fontinalis.Here's a pic of D. tomentosa var. tomentosa (L) and D.X fontinalis ®: Edited June 18, 2014 by Fernando Rivadavia 2 Quote Link to comment Share on other sites More sharing options...
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