flowering 'juvenilies'

From: "Peter Boyce" p.boyce at rbgkew.org.uk> on 2000.06.15 at 21:45:46(4787) Dear All The newly raised issue of juvenile monsteroids flowering is interesting because, while the production of flowers by a plant vegetatively in a juvenile phase does occur in the monsteroids, notably Monstera tuberculata, Rhaphidophora hayi, R. latevaginata, R. pachyphylla, R. parvifolia, R. okapensis and Scindapsus lucens, this 'M. dubia' thing is that the plants are flowering with very small leaves and BENEATH the leaves, whereas in all of those listed above while the juvenile growth morphology is retained into flowering in most instances the leaves of flowering individuals are considerably larger than those of youngsters and the inflorescences are carried clear of the leaves either at the tips of clinging shoots or on free shoots arising from the leaf axils. If the description of this 'dubia' plant is correct it would appear that inflorescences are arising directly from the leaf axils. Because aroids ALWAYS flower at the shoot apex it would mean that in this plant each inflorescence is carried at the tip of a very short shoot arising in the leaf axil (the same situation as in Pothos scandens) - a feature not yet recorded in the Monstereae. Pete +More ---------------------------- Peter Boyce Herbarium Royal Botanic Gardens, Kew Richmond, Surrey TW9 3AE Tel. (+44) (0)20 8 332 5207 fax. (+44) (0)20 8 332 5278 email: p.boyce@rbgkew.org.uk (work) boyce@pothos.demon.co.uk (home)

From: "Eduardo Goncalves" edggon at hotmail.com> on 2000.06.16 at 02:41:04(4796) Dear Aroiders, The production of sexual parts in juvenile individuals is a morphogenetic "accident", but it is usually explored by the evolutionary history of many groups. There are two morphogenetic processes associated to this aspect: Paedomorphosis and Neoteny. Both concern juvenile individuals with mature sexual parts or juvenile structures that are kept active in adult individuals. These phenomenons occur in both plants and animals. Some evolutionists say that humans are just neotenic apes, because our brain continues to develop for a long time after birth! Anyhow, theses processes are also know in plants and maybe they are a good natural method to "make" new species. Juvenile (or poorly diferenciated) organs are usually very plastic and can adapt to different conditions. If this ability to be morphologically plastic is important for the effective survival of a quoted species, it can be kept or even "improved" by natural selection. I have one possible example. One of the most morphologically variable genus in the tribe Spathicarpeae is Spathicarpa. It is small, with poorly differenciated ground tissues and have usually the simplest leaf type in the tribe (I mean the same type we find in seedlings of almost all genera of the tribe). One of my hypothesis (still in test) is that Spathicarpa is a neotenic genus in Spathicarpeae. The same for Urospathella wurdackii G.S.Bunting (now currently recognized as Urospatha wurdackii (G.S.Bunting) Hay). It is a Urospatha that flowers with the leaves of seedlings!!!! Maybe this kind of leaf is useful in those savannas this species occurs. Or maybe it is just an accident that soon will be erased by natural selection! In the case of the supposed M. dubia that flowers with juvenile flowers, we can make some free speculation about this. In the "normal" environment of the species, maybe it is not a good idea flowering this way, because pollinators may not be able to find the flowers. Meanwhile, if this plant spread to new areas, maybe with smaller trees and different potential pollinators, it can prove to be successful (in evolutionary aspects), so it can diverge from the main species and become ANOTHER species. If evolution can be so creative than me (I don't think so), it is really possible to occur in nature! +More I hope you enjoy those crazy ideas!! :o) Eduardo. >From: "Peter Boyce" >Reply-To: aroid-l@mobot.org >To: Multiple recipients of list AROID-L >Subject: flowering 'juvenilies' >Date: Thu, 15 Jun 2000 16:45:43 -0500 (CDT) > >Dear All > >The newly raised issue of juvenile monsteroids flowering is >interesting because, while the production of flowers by a plant >vegetatively in a juvenile phase does occur in the monsteroids, >notably Monstera tuberculata, Rhaphidophora hayi, R. latevaginata, >R. pachyphylla, R. parvifolia, R. okapensis and Scindapsus lucens, >this 'M. dubia' thing is that the plants are flowering with very small >leaves and BENEATH the leaves, whereas in all of those listed >above while the juvenile growth morphology is retained into >flowering in most instances the leaves of flowering individuals are >considerably larger than those of youngsters and the >inflorescences are carried clear of the leaves either at the tips of >clinging shoots or on free shoots arising from the leaf axils. If the >description of this 'dubia' plant is correct it would appear that >inflorescences are arising directly from the leaf axils. Because >aroids ALWAYS flower at the shoot apex it would mean that in this >plant each inflorescence is carried at the tip of a very short shoot >arising in the leaf axil (the same situation as in Pothos scandens) - >a feature not yet recorded in the Monstereae. > >Pete > >---------------------------- >Peter Boyce >Herbarium >Royal Botanic Gardens, Kew >Richmond, Surrey >TW9 3AE >Tel. (+44) (0)20 8 332 5207 >fax. (+44) (0)20 8 332 5278 >email: p.boyce@rbgkew.org.uk (work) > boyce@pothos.demon.co.uk (home) > > > ________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com

From: Don Burns donburns at macconnect.com> on 2000.06.17 at 00:36:39(4800) >Date: Fri, 16 Jun 2000 19:25:30 -0500 (CDT) >Reply-To: webmaster@plantapalm.com >Originator: aroid-l@mobot.org +More >Sender: aroid-l@mobot.org >Precedence: bulk >From: Jody Haynes >To: aroid-owner@mobot.org >Subject: Re: flowering 'juvenilies' >MIME-Version: 1.0 > >This message was submitted by Jody Haynes to list >aroid-l@mobot.org. If you forward it back to the list, it will be distributed >without the paragraphs above the dashed line. You may edit the Subject: line >and the text of the message before forwarding it back. > >If you edit the messages you receive into a digest, you will need to remove >these paragraphs and the dashed line before mailing the result to the list. >Finally, if you need more information from the author of this message, you >should be able to do so by simply replying to this note. > >----------------------- Message requiring your approval ---------------------- >Sender: Jody Haynes >Subject: Re: flowering 'juvenilies' > >Eduardo, >Yours was an interesting post. I, too, have some knowledge (and an astute >interest) of paedomorphosis and neoteny--but only in animals. I was not >aware of >the process in plants. > >I feel that these terms should be clarified. Although they both refer to the >"possession in the adult stage of features typical of the juvenile stage >of the >organism's ancestor", neoteny specifically refers to sexual maturation of the >'juvenile' stage: "heterochronic evolution whereby development of some or all >somatic features is retarded relative to sexual maturation, resulting in >sexually mature individuals with juvenile features" (Futuyma, D. J. 1986. >Evolutionary Biology. Sinauer Associates, Inc. Sunderland, MA.). > >Thus, paedomorphosis refers to the simple possession of juvenile traits in an >adult organism, but does not specify a process; conversely, neoteny is the >process by which somatic maturation is retarded relative to sexual maturation. > >Does this make sense? Anyone else care to comment on this interesting topic? >Jody >-- >Jody Haynes >Corresponding Secretary, Editor & Webmaster >Palm & Cycad Societies of Florida (PACSOF) > Virtual Palm & Cycad Encyclopedias > Website: > & >Seedbank Facilitator, Webmaster & List Owner >Azafady Madagascar Seedbank > Website: > E-mail List: > >Eduardo Goncalves wrote: > >> Dear Aroiders, >> >> The production of sexual parts in juvenile individuals is a >> morphogenetic "accident", but it is usually explored by the evolutionary >> history of many groups. There are two morphogenetic processes associated to >> this aspect: Paedomorphosis and Neoteny. Both concern juvenile individuals >> with mature sexual parts or juvenile structures that are kept active in >> adult individuals. These phenomenons occur in both plants and animals. Some >> evolutionists say that humans are just neotenic apes, because our brain >> continues to develop for a long time after birth! Anyhow, theses processes >> are also know in plants and maybe they are a good natural method to "make" >> new species. Juvenile (or poorly diferenciated) organs are usually very >> plastic and can adapt to different conditions. If this ability to be >> morphologically plastic is important for the effective survival of a quoted >> species, it can be kept or even "improved" by natural selection. >> I have one possible example. One of the most morphologically variable >> genus in the tribe Spathicarpeae is Spathicarpa. It is small, with poorly >> differenciated ground tissues and have usually the simplest leaf type in the >> tribe (I mean the same type we find in seedlings of almost all genera of >> the tribe). One of my hypothesis (still in test) is that Spathicarpa is a >> neotenic genus in Spathicarpeae. The same for Urospathella wurdackii >> G.S.Bunting (now currently recognized as Urospatha wurdackii (G.S.Bunting) >> Hay). It is a Urospatha that flowers with the leaves of seedlings!!!! Maybe >> this kind of leaf is useful in those savannas this species occurs. Or maybe >> it is just an accident that soon will be erased by natural selection! >> In the case of the supposed M. dubia that flowers with juvenile >> flowers, we can make some free speculation about this. In the "normal" >> environment of the species, maybe it is not a good idea flowering this way, >> because pollinators may not be able to find the flowers. Meanwhile, if this >> plant spread to new areas, maybe with smaller trees and different potential >> pollinators, it can prove to be successful (in evolutionary aspects), so it >> can diverge from the main species and become ANOTHER species. If evolution >> can be so creative than me (I don't think so), it is really possible to >> occur in nature! >> >> I hope you enjoy those crazy ideas!! :o) >> >> Eduardo. >> >> >From: "Peter Boyce" >> >Reply-To: aroid-l@mobot.org >> >To: Multiple recipients of list AROID-L >> >Subject: flowering 'juvenilies' >> >Date: Thu, 15 Jun 2000 16:45:43 -0500 (CDT) >> > >> >Dear All >> > >> >The newly raised issue of juvenile monsteroids flowering is >> >interesting because, while the production of flowers by a plant >> >vegetatively in a juvenile phase does occur in the monsteroids, >> >notably Monstera tuberculata, Rhaphidophora hayi, R. latevaginata, >> >R. pachyphylla, R. parvifolia, R. okapensis and Scindapsus lucens, >> >this 'M. dubia' thing is that the plants are flowering with very small >> >leaves and BENEATH the leaves, whereas in all of those listed >> >above while the juvenile growth morphology is retained into >> >flowering in most instances the leaves of flowering individuals are >> >considerably larger than those of youngsters and the >> >inflorescences are carried clear of the leaves either at the tips of >> >clinging shoots or on free shoots arising from the leaf axils. If the >> >description of this 'dubia' plant is correct it would appear that >> >inflorescences are arising directly from the leaf axils. Because >> >aroids ALWAYS flower at the shoot apex it would mean that in this >> >plant each inflorescence is carried at the tip of a very short shoot >> >arising in the leaf axil (the same situation as in Pothos scandens) - >> >a feature not yet recorded in the Monstereae. >> > >> >Pete >> > >> >---------------------------- >> >Peter Boyce >> >Herbarium >> >Royal Botanic Gardens, Kew >> >Richmond, Surrey >> >TW9 3AE >> >Tel. (+44) (0)20 8 332 5207 >> >fax. (+44) (0)20 8 332 5278 >> >email: p.boyce@rbgkew.org.uk (work) >> > boyce@pothos.demon.co.uk (home) >> > >> > >

From: Jody Haynes webmaster at plantapalm.com> on 2000.06.17 at 00:49:40(4806) Eduardo, Yours was an interesting post. I, too, have some knowledge (and an astute interest) of paedomorphosis and neoteny--but only in animals. I was not aware of the process in plants. I feel that these terms should be clarified. Although they both refer to the "possession in the adult stage of features typical of the juvenile stage of the organism's ancestor", neoteny specifically refers to sexual maturation of the 'juvenile' stage: "heterochronic evolution whereby development of some or all somatic features is retarded relative to sexual maturation, resulting in sexually mature individuals with juvenile features" (Futuyma, D. J. 1986. Evolutionary Biology. Sinauer Associates, Inc. Sunderland, MA.). Thus, paedomorphosis refers to the simple possession of juvenile traits in an adult organism, but does not specify a process; conversely, neoteny is the process by which somatic maturation is retarded relative to sexual maturation. Does this make sense? Anyone else care to comment on this interesting topic? Jody +More -- Jody Haynes Corresponding Secretary, Editor & Webmaster Palm & Cycad Societies of Florida (PACSOF) Virtual Palm & Cycad Encyclopedias Website: & Seedbank Facilitator, Webmaster & List Owner Azafady Madagascar Seedbank Website: E-mail List: Eduardo Goncalves wrote: > Dear Aroiders, > > The production of sexual parts in juvenile individuals is a > morphogenetic "accident", but it is usually explored by the evolutionary > history of many groups. There are two morphogenetic processes associated to > this aspect: Paedomorphosis and Neoteny. Both concern juvenile individuals > with mature sexual parts or juvenile structures that are kept active in > adult individuals. These phenomenons occur in both plants and animals. Some > evolutionists say that humans are just neotenic apes, because our brain > continues to develop for a long time after birth! Anyhow, theses processes > are also know in plants and maybe they are a good natural method to "make" > new species. Juvenile (or poorly diferenciated) organs are usually very > plastic and can adapt to different conditions. If this ability to be > morphologically plastic is important for the effective survival of a quoted > species, it can be kept or even "improved" by natural selection. > I have one possible example. One of the most morphologically variable > genus in the tribe Spathicarpeae is Spathicarpa. It is small, with poorly > differenciated ground tissues and have usually the simplest leaf type in the > tribe (I mean the same type we find in seedlings of almost all genera of > the tribe). One of my hypothesis (still in test) is that Spathicarpa is a > neotenic genus in Spathicarpeae. The same for Urospathella wurdackii > G.S.Bunting (now currently recognized as Urospatha wurdackii (G.S.Bunting) > Hay). It is a Urospatha that flowers with the leaves of seedlings!!!! Maybe > this kind of leaf is useful in those savannas this species occurs. Or maybe > it is just an accident that soon will be erased by natural selection! > In the case of the supposed M. dubia that flowers with juvenile > flowers, we can make some free speculation about this. In the "normal" > environment of the species, maybe it is not a good idea flowering this way, > because pollinators may not be able to find the flowers. Meanwhile, if this > plant spread to new areas, maybe with smaller trees and different potential > pollinators, it can prove to be successful (in evolutionary aspects), so it > can diverge from the main species and become ANOTHER species. If evolution > can be so creative than me (I don't think so), it is really possible to > occur in nature! > > I hope you enjoy those crazy ideas!! :o) > > Eduardo. > > >From: "Peter Boyce" > >Reply-To: aroid-l@mobot.org > >To: Multiple recipients of list AROID-L > >Subject: flowering 'juvenilies' > >Date: Thu, 15 Jun 2000 16:45:43 -0500 (CDT) > > > >Dear All > > > >The newly raised issue of juvenile monsteroids flowering is > >interesting because, while the production of flowers by a plant > >vegetatively in a juvenile phase does occur in the monsteroids, > >notably Monstera tuberculata, Rhaphidophora hayi, R. latevaginata, > >R. pachyphylla, R. parvifolia, R. okapensis and Scindapsus lucens, > >this 'M. dubia' thing is that the plants are flowering with very small > >leaves and BENEATH the leaves, whereas in all of those listed > >above while the juvenile growth morphology is retained into > >flowering in most instances the leaves of flowering individuals are > >considerably larger than those of youngsters and the > >inflorescences are carried clear of the leaves either at the tips of > >clinging shoots or on free shoots arising from the leaf axils. If the > >description of this 'dubia' plant is correct it would appear that > >inflorescences are arising directly from the leaf axils. Because > >aroids ALWAYS flower at the shoot apex it would mean that in this > >plant each inflorescence is carried at the tip of a very short shoot > >arising in the leaf axil (the same situation as in Pothos scandens) - > >a feature not yet recorded in the Monstereae. > > > >Pete > > > >---------------------------- > >Peter Boyce > >Herbarium > >Royal Botanic Gardens, Kew > >Richmond, Surrey > >TW9 3AE > >Tel. (+44) (0)20 8 332 5207 > >fax. (+44) (0)20 8 332 5278 > >email: p.boyce@rbgkew.org.uk (work) > > boyce@pothos.demon.co.uk (home) > > > >

From: StellrJ at aol.com on 2000.06.19 at 02:22:57(4832) In a message dated Fri, 16 Jun 2000 8:50:17 PM Eastern Daylight Time, Jody Haynes writes: Thus, paedomorphosis refers to the simple possession of juvenile traits in an +More adult organism, but does not specify a process; conversely, neoteny is the process by which somatic maturation is retarded relative to sexual maturation. Does this make sense? Anyone else care to comment on this interesting topic? So, what you are saying is, paedomorphosis is when an adult looks or acts like a juvenile, while neoteny is when a juvenile is capable of reproducing? So, in human terms, certain males of our species are behaviorally paedomorphic, while teenage mothers are cases of neoteny. Jason Hernandez Naturalist-at-Large -- Jody Haynes Corresponding Secretary, Editor & Webmaster Palm & Cycad Societies of Florida (PACSOF) Virtual Palm & Cycad Encyclopedias Website: & Seedbank Facilitator, Webmaster & List Owner Azafady Madagascar Seedbank Website: E-mail List: Eduardo Goncalves wrote: > Dear Aroiders, > > The production of sexual parts in juvenile individuals is a > morphogenetic "accident", but it is usually explored by the evolutionary > history of many groups. There are two morphogenetic processes associated to > this aspect: Paedomorphosis and Neoteny. Both concern juvenile individuals > with mature sexual parts or juvenile structures that are kept active in > adult individuals. These phenomenons occur in both plants and animals. Some > evolutionists say that humans are just neotenic apes, because our brain > continues to develop for a long time after birth! Anyhow, theses processes > are also know in plants and maybe they are a good natural method to "make" > new species. Juvenile (or poorly diferenciated) organs are usually very > plastic and can adapt to different conditions. If this ability to be > morphologically plastic is important for the effective survival of a quoted > species, it can be kept or even "improved" by natural selection. > I have one possible example. One of the most morphologically variable > genus in the tribe Spathicarpeae is Spathicarpa. It is small, with poorly > differenciated ground tissues and have usually the simplest leaf type in the > tribe (I mean the same type we find in seedlings of almost all genera of > the tribe). One of my hypothesis (still in test) is that Spathicarpa is a > neotenic genus in Spathicarpeae. The same for Urospathella wurdackii > G.S.Bunting (now currently recognized as Urospatha wurdackii (G.S.Bunting) > Hay). It is a Urospatha that flowers with the leaves of seedlings!!!! Maybe > this kind of leaf is useful in those savannas this species occurs. Or maybe > it is just an accident that soon will be erased by natural selection! > In the case of the supposed M. dubia that flowers with juvenile > flowers, we can make some free speculation about this. In the "normal" > environment of the species, maybe it is not a good idea flowering this way, > because pollinators may not be able to find the flowers. Meanwhile, if this > plant spread to new areas, maybe with smaller trees and different potential > pollinators, it can prove to be successful (in evolutionary aspects), so it > can diverge from the main species and become ANOTHER species. If evolution > can be so creative than me (I don't think so), it is really possible to > occur in nature! > > I hope you enjoy those crazy ideas!! :o) > > Eduardo. > > >From: "Peter Boyce" > >Reply-To: aroid-l@mobot.org > >To: Multiple recipients of list AROID-L > >Subject: flowering 'juvenilies' > >Date: Thu, 15 Jun 2000 16:45:43 -0500 (CDT) > > > >Dear All > > > >The newly raised issue of juvenile monsteroids flowering is > >interesting because, while the production of flowers by a plant > >vegetatively in a juvenile phase does occur in the monsteroids, > >notably Monstera tuberculata, Rhaphidophora hayi, R. latevaginata, > >R. pachyphylla, R. parvifolia, R. okapensis and Scindapsus lucens, > >this 'M. dubia' thing is that the plants are flowering with very small > >leaves and BENEATH the leaves, whereas in all of those listed > >above while the juvenile growth morphology is retained into > >flowering in most instances the leaves of flowering individuals are > >considerably larger than those of youngsters and the > >inflorescences are carried clear of the leaves either at the tips of > >clinging shoots or on free shoots arising from the leaf axils. If the > >description of this 'dubia' plant is correct it would appear that > >inflorescences are arising directly from the leaf axils. Because > >aroids ALWAYS flower at the shoot apex it would mean that in this > >plant each inflorescence is carried at the tip of a very short shoot > >arising in the leaf axil (the same situation as in Pothos scandens) - > >a feature not yet recorded in the Monstereae. > > > >Pete > > > >---------------------------- > >Peter Boyce > >Herbarium > >Royal Botanic Gardens, Kew > >Richmond, Surrey > >TW9 3AE > >Tel. (+44) (0)20 8 332 5207 > >fax. (+44) (0)20 8 332 5278 > >email: p.boyce@rbgkew.org.uk (work) > > boyce@pothos.demon.co.uk (home) > > > > >>

From: Jody Haynes webmaster at plantapalm.com> on 2000.06.19 at 21:26:39(4843) > So, what you are saying is, paedomorphosis is when an adult looks or acts > like a juvenile, while neoteny is when a juvenile is capable of reproducing? Yes and no. Neoteny is the *process* of retardation of somatic maturation relative to sexual maturation, whereas paedomorphosis is the *possession* of juvenile traits in an adult. > So, in human terms, certain males of our species are behaviorally +More > paedomorphic, while teenage mothers are cases of neoteny. Yes and no. Teenage mothers are not cases of neoteny, because they are essentially morphological adults. Furthermore, in both neoteny and peademorphosis, juvenile traits are retained throughout the organism's life. > Jason Hernandez > Naturalist-at-Large Does this help? Jody

From: Lewandjim at aol.com on 2000.06.19 at 21:28:05(4847) In a message dated 06/18/2000 10:23:21 PM Eastern Daylight Time was written: << So, what you are saying is, paedomorphosis is when an adult looks or acts like a juvenile, while neoteny is when a juvenile is capable of reproducing? So, in human terms, certain males of our species are behaviorally paedomorphic, while teenage mothers are cases of neoteny. Jason Hernandez +More Naturalist-at-Large >> Hi Jason, I like your "tonge-in-cheek" humor! but I think you are a bit off kilter with saying "neoteny is when a juvenile is capable of reproducing?" Neoteny is a really complex subject and I'm NO AUTHORITY! It does NOT however usually refer to individuals but to entire phylogenetic groups (involving differing taxon levels). A simple example are the axolotls - a group of salamanders that are locked into permanent juvenile (= tadpole) life as "adults". They do not metamorphose but retain gills and the tail fin throughout physiological reproductive maturity. In the case of the species Ambystoma mexicanum, neoteny characterizes the entire population because it is genetically based in the inability to UTILIZE the hormones for metamorphosis. However, as exemplification of the diversity in Nature - there are certain populations of newts and the tiger salamander that are neotenic because the lack of iodide in their habitat prevents them from MAKING the hormones for metamorphosis. Jim Langhammer

From: "Eduardo Goncalves" edggon at hotmail.com> on 2000.06.21 at 01:59:48(4867) Dear Jody, Thanks for your comments. In my post, I just forgot to include a good definition of both terms. You did it with precision! I hope someone have other possible examples with other groups in this marvelous family. Best wishes, Eduardo. +More >From: Jody Haynes >Reply-To: aroid-l@mobot.org >To: Multiple recipients of list AROID-L >Subject: Re: flowering 'juvenilies' >Date: Fri, 16 Jun 2000 19:49:38 -0500 (CDT) > >Eduardo, >Yours was an interesting post. I, too, have some knowledge (and an astute >interest) of paedomorphosis and neoteny--but only in animals. I was not >aware of >the process in plants. > >I feel that these terms should be clarified. Although they both refer to >the >"possession in the adult stage of features typical of the juvenile stage of >the >organism's ancestor", neoteny specifically refers to sexual maturation of >the >'juvenile' stage: "heterochronic evolution whereby development of some or >all >somatic features is retarded relative to sexual maturation, resulting in >sexually mature individuals with juvenile features" (Futuyma, D. J. 1986. >Evolutionary Biology. Sinauer Associates, Inc. Sunderland, MA.). > >Thus, paedomorphosis refers to the simple possession of juvenile traits in >an >adult organism, but does not specify a process; conversely, neoteny is the >process by which somatic maturation is retarded relative to sexual >maturation. > >Does this make sense? Anyone else care to comment on this interesting >topic? >Jody >-- >Jody Haynes >Corresponding Secretary, Editor & Webmaster >Palm & Cycad Societies of Florida (PACSOF) > Virtual Palm & Cycad Encyclopedias > Website: > & >Seedbank Facilitator, Webmaster & List Owner >Azafady Madagascar Seedbank > Website: > E-mail List: > >Eduardo Goncalves wrote: > > > Dear Aroiders, > > > > The production of sexual parts in juvenile individuals is a > > morphogenetic "accident", but it is usually explored by the evolutionary > > history of many groups. There are two morphogenetic processes associated >to > > this aspect: Paedomorphosis and Neoteny. Both concern juvenile >individuals > > with mature sexual parts or juvenile structures that are kept active in > > adult individuals. These phenomenons occur in both plants and animals. >Some > > evolutionists say that humans are just neotenic apes, because our brain > > continues to develop for a long time after birth! Anyhow, theses >processes > > are also know in plants and maybe they are a good natural method to >"make" > > new species. Juvenile (or poorly diferenciated) organs are usually very > > plastic and can adapt to different conditions. If this ability to be > > morphologically plastic is important for the effective survival of a >quoted > > species, it can be kept or even "improved" by natural selection. > > I have one possible example. One of the most morphologically >variable > > genus in the tribe Spathicarpeae is Spathicarpa. It is small, with >poorly > > differenciated ground tissues and have usually the simplest leaf type in >the > > tribe (I mean the same type we find in seedlings of almost all genera >of > > the tribe). One of my hypothesis (still in test) is that Spathicarpa is >a > > neotenic genus in Spathicarpeae. The same for Urospathella wurdackii > > G.S.Bunting (now currently recognized as Urospatha wurdackii >(G.S.Bunting) > > Hay). It is a Urospatha that flowers with the leaves of seedlings!!!! >Maybe > > this kind of leaf is useful in those savannas this species occurs. Or >maybe > > it is just an accident that soon will be erased by natural selection! > > In the case of the supposed M. dubia that flowers with juvenile > > flowers, we can make some free speculation about this. In the "normal" > > environment of the species, maybe it is not a good idea flowering this >way, > > because pollinators may not be able to find the flowers. Meanwhile, if >this > > plant spread to new areas, maybe with smaller trees and different >potential > > pollinators, it can prove to be successful (in evolutionary aspects), so >it > > can diverge from the main species and become ANOTHER species. If >evolution > > can be so creative than me (I don't think so), it is really possible to > > occur in nature! > > > > I hope you enjoy those crazy ideas!! :o) > > > > Eduardo. > > > > >From: "Peter Boyce" > > >Reply-To: aroid-l@mobot.org > > >To: Multiple recipients of list AROID-L > > >Subject: flowering 'juvenilies' > > >Date: Thu, 15 Jun 2000 16:45:43 -0500 (CDT) > > > > > >Dear All > > > > > >The newly raised issue of juvenile monsteroids flowering is > > >interesting because, while the production of flowers by a plant > > >vegetatively in a juvenile phase does occur in the monsteroids, > > >notably Monstera tuberculata, Rhaphidophora hayi, R. latevaginata, > > >R. pachyphylla, R. parvifolia, R. okapensis and Scindapsus lucens, > > >this 'M. dubia' thing is that the plants are flowering with very small > > >leaves and BENEATH the leaves, whereas in all of those listed > > >above while the juvenile growth morphology is retained into > > >flowering in most instances the leaves of flowering individuals are > > >considerably larger than those of youngsters and the > > >inflorescences are carried clear of the leaves either at the tips of > > >clinging shoots or on free shoots arising from the leaf axils. If the > > >description of this 'dubia' plant is correct it would appear that > > >inflorescences are arising directly from the leaf axils. Because > > >aroids ALWAYS flower at the shoot apex it would mean that in this > > >plant each inflorescence is carried at the tip of a very short shoot > > >arising in the leaf axil (the same situation as in Pothos scandens) - > > >a feature not yet recorded in the Monstereae. > > > > > >Pete > > > > > >---------------------------- > > >Peter Boyce > > >Herbarium > > >Royal Botanic Gardens, Kew > > >Richmond, Surrey > > >TW9 3AE > > >Tel. (+44) (0)20 8 332 5207 > > >fax. (+44) (0)20 8 332 5278 > > >email: p.boyce@rbgkew.org.uk (work) > > > boyce@pothos.demon.co.uk (home) > > > > > > > > > ________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com

From: StellrJ at aol.com on 2000.06.21 at 02:59:48(4868) In a message dated Mon, 19 Jun 2000 5:33:21 PM Eastern Daylight Time, Jody Haynes write: > So, what you are saying is, paedomorphosis is when an adult looks or acts +More > like a juvenile, while neoteny is when a juvenile is capable of reproducing? Yes and no. Neoteny is the *process* of retardation of somatic maturation relative to sexual maturation, whereas paedomorphosis is the *possession* of juvenile traits in an adult. Does this help? Jody Yes, very much. You are distingushing an outward manifestation from the process that causes it. Jason Hernandez Naturalist-at-Large

From: Jody Haynes webmaster at plantapalm.com> on 2000.06.21 at 03:11:21(4871) Thank you, Eduardo. I, too, look forward to more information on this topic. Eduardo Goncalves wrote: > Dear Jody, +More > > Thanks for your comments. In my post, I just forgot to include a good > definition of both terms. You did it with precision! I hope someone have > other possible examples with other groups in this marvelous family. > > Best wishes, > > Eduardo.

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