Re: [Aroid-l] Philodendron stenolobum

From: Neil Crafter golfstra at senet.com.au> on 2005.07.03 at 01:17:56(13104) Julius Very clear and message received. I guess it's hard for us amateurs who do not have access to herbarium material, microscopes, gynoeciums and locules (let alone flowering material - my old P. 'williamsii' is at least 20 years old and has never flowered) to try and identify the plants in our collections. For myself, the tendency to rely on what I can observe of the plants is perhaps overwhelming at times, especially when the division between species may come down to microscopic structural differences in their flowers. Having further examined my old'williamsii' and new stenolobum, I am struck by the similarities in petiole cross section and trunk appearance, with the only apparent 'difference' being the leaf blade shape and its stiffness. This problem with P 'williamsii' would appear to go a long way back. I have a copy in my files of a beautiful coloured drawing and the first description of P. williamsii in one of the early botanical publications, the Botanical Magazine (5899) - the plant looks like stenolobum more than the longer bladed variation. The author had the initials of JBH (Hooker?) and he described the plant as being sent to Kew by Mr Williams of Bahia, giving it the name of Philodendron williamsii. The paper has a date of May 1871. A question for Eduardo. Is this the true P.williamsii you refer to which is only known from some herbarium material? or was this plant misnamed from the start. cheers Neil Neil Crafter +More Philodendron enthusiast Adelaide, Australia On 03/07/2005, at 6:48 AM, Julius Boos wrote: Sent : Saturday, July 2, 2005 7:40 PM To : Discussion of aroids Subject : Re: [Aroid-l] Philodendron stenolobum Dear ALl, I still do not think you guys understand what is being said--- ALL these photos that are being discussed, plants with the longer narrower ruffled leaf blades, the long FLAT leaf blades, the slightly shorter leaf blades with or without ruffles, slightly longer lobes, slightly shorter lobes, ALL are variations from different collections throughout the range of P. stenolobum, a range FAR distant from where TRUE P. williamsii occurs. NONE of the plants being seen or discussed are a different species OR P. williamsii. Leaf shape or leaf lobe shape/length play a VERY minor role in the determination of species. ALL the plants pictured and being discussed should or will have barrel-shaped gynociums (not flask-shaped as in P. williamsii), ALL will have only 7-8 locules (not 11-12 as is found in P. williamsii) and all will fall within the anterior leaf blade ratio of P. stenolobum, so ALL will be classified as P. stenolobum, NOT another species, and NOT P. williamsii. If it rings your bells, or makes them more expensive/easier to sell, knock yourself out and give them 'cultivar' or 'var.' names, but this only confuses the issue further. Read and understand Dr. Goncalves recent postings. Good Growing! Julius Very nicely put! As you say, some cultivated samples may tend to be those that are "extreme" samples from the wild, and thus are not truly representative of the "average" look of the species (that is, the wild population may form a continuum of plant forms). The pic of one of the leaves of that small plant called "P. williamsii" shows short lobes but with edges that are ruffled (and some of newer leaves just coming out are starting to get even more 'wavy'): http://www.blueboard.com/pahatan/gambar/images/ 2005_7_1_asj_p_stenolobum_1.jpg I looked at pics of P. stenolobum from that paper and they look similar in lobe shape to the short form - so maybe it's the "long lobe" form that needs a new name - LOL.... But, honestly, i do like the ones with longer, thinner lobes though ;-) --- Julius Boos wrote: >From : a san juan Reply-To : Discussion of aroids Sent : Friday, July 1, 2005 9:21 PM To : Discussion of aroids Subject : Re: [Aroid-l] Philodendron stenolobum Dear Friends, Eduardo has informed us of exactly what the case is w/ these two very different and 'good' species (see his letter of 30th, 8.18 pm, addressed to 'Tom" (Dr. Croat), but allow me one more explanation on what might have and may still be causing some confusion. [By the way, the leaf ratios asked for on these two species are---"Anterior division (ratio length/width) P. williamsii--1 - 1.5. P. stenolobum 2.1 - 3.3. (these are copied from Dr. Gonclaves' paper) Other critical differences that separate these two species documented by Dr. Goncalves in his paper are--The gynoceum (immature fruit) in P. stenolobum is flask-shaped, while that of P. williamsii is barrel shaped. The ovary of P. stenolobum has 11-12 locules (chambers) while that of P. williamsii has only 7-8.] Before Dr. Goncalves published his paper, when word got out that the plant that we all had been refering to as P. williamsii was going to be described as a new/good species, several collectors/growers then assumed that only the plants with the ruffled leaf edges were this new species ( P. stenolobum), and the plants with the not-so-long anterior lobes and flat leaf blades must still be P. williamsii--- we were wrong! The TRUE P. williamsii is a completely different species, seemingly not in cultivation, rare in herbarium collections, and very different looking to either one of the vars. of the now-new P. stenolobum, and grows FAR away from all the different populations of the new P. stenolobum. (see Eduardo`s recent letter on this). So--the plants that have a very long leaf, both the ruffled and the unruffled, ALL are TRUE P. stenolobum. Man ALWAYS gravitates to collecting from wild populations what he views as the most attractive or even odd members of a broard variety of either plants or animals, it happens all the time with collectors, but true scientists collect 'down the middle', a representitive sample that illustrates the extremes of a species. This obviously pertains to the plants under discussion, all seen are P. stenolobum. Julius WPB, Florida >>Could you give numbers for the ratios? I'm curious, and glad this conversation came up.<< --- Russ wrote: > >The leaves on my 'stenolobum' are nowhere near as >ruffled as the one in last year's Aroid show, or the >2 pictures I found >of P. 'williamsii' in my Exotica. But they seem to >be the same in narrow lobe width and proportions. So, these are obviously >both stenolobum with a >variation in the leaf edge. BUT, these are not the >two opposing plants I have in mind as questionable. The 'old williamsii' >that I'm referencing has much >shorter, and wider lobes, and leaves are not as >thick or stiff. They truly do not look like the >same species. Russ> _______________________________________________ >Aroid-l mailing list >Aroid-l@gizmoworks.com >http://www.gizmoworks.com/mailman/listinfo/aroid-l > ____________________________________________________ Yahoo! Sports Rekindle the Rivalries. 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