Gurcharanji I found a univ of queensland teaching manual ... in it they describe exactly the two leaf types you just talked of... I am sending the url in for sake of sharing with other non-botanists like me and for sake of completion for archives... Thanks again Usha di ========
On Fri, Mar 23, 2012 at 11:44 AM, Gurcharan Singh <[email protected]>wrote: > Ushadi > There is a famous doctrine in Biology which all of us are familiar with > "Ontogeny Repeats Phyllogeny". The modified leaf of Australian Acacia > (Acacia auriculiformis) is derived from the normal bipinnate leaves so > common in other Acacia species. In this evolutionary modification the > pinnae got reduced and their function was taken up by the flattened petiole > (called Phyllode, as against phylloclade of Opuntia which is a modified > stem taking function of leaf) of the leaf in the adult plant. Hence it is > common to see juvenile plants with some pinnae at the tip of the phyllode, > and these eventually fall off. Adult trees are without these pinnae and > have only flattened phyllodes functioning as leaves. Of course every leaf > has to fall once it has become old: In evergreen trees they develop and > fall off periodically so that tree remains green throughout the year > (Mango, Alstonia, etc.); In deciduous trees on the other hand the fresh > leaves appear in spring (Late February-March-early April) and all fall off > in autumn so that tree remains naked for few months in winter (Prunus, > Pyrus, Salix, Populus). > Delhi (and perhaps some other warmer cities in India) don't have typical > four seasons. Here so called autumn is brief few days in March when > deciduous trees suddenly lose their leaves and fresh leaves come up after a > gap of few days, the Delhi Spring. > > I hope I have shared some helpful information. > > -- > Dr. Gurcharan Singh > Retired Associate Professor > SGTB Khalsa College, University of Delhi, Delhi-110007 > Res: 932 Anand Kunj, Vikas Puri, New Delhi-110018. > Phone: 011-25518297 Mob: 9810359089 > http://www.gurcharanfamily.com/ > http://people.du.ac.in/~singhg45/ > > > On Fri, Mar 23, 2012 at 10:44 AM, shrikant ingalhalikar < > [email protected]> wrote: > >> Dear Usha di, >> >> Wish you a happy Hindu New Year. Thank you very much for your >> curiosities, hope I satisfy them at least partially. >> >> This is my first attempt to handle the new format yet I believe that my >> post carries the name Acacia auriculiformis. Ironically the post itself >> became more intriguing than the leaves. Earleaf Acacia and Australian >> Acacia are more names to help you navigate with Google. Pardon me for >> defficient and confusing information. I am attaching another image to help >> you ID this invasive tree that has reached most of our wild habitats. >> >> I am also a pitiable non botanist like most of us. Please excuse me to >> have narrated in a style that disguises me to be a card carrying botanist. >> I take privilege of passing the batton of your queries to a person who >> carries the necessary stars and shoulder pips.With regards.Shrikant >> >> >> >> >> >> >> On Thursday, March 22, 2012 10:02:53 PM UTC+5:30, Ushadi wrote: >> >>> BUT I am still ignorant of the tree's ID and >>> what happens when that flat "leaf " falls off, does it mean that the >>> small leaves on its apex fall off too? >>> so some leaves have pinnae and some donot? as in this pic... >>> >>> if I knew the name , I could google it... >>> then I would not have to bother you... >>> >>> but all this discussion without a name, assumes that most of the 1900 >>> members are all botanists... REMEMBER ONLY A HANDFUL ARE CARD CARRYING >>> BOTANISTS>> THE REST OF US are NON BOTANISTS.... so please take pity on >>> us .... >>> >>> thanks >>> Usha di >>> ==== >>> >>> >>> >>> On Thu, Mar 22, 2012 at 8:30 PM, Satish Phadke <[email protected]>wrote: >>> >>>> Very good illustration. >>>> >>>> On Thu, Mar 22, 2012 at 7:20 PM, shrikant ingalhalikar < >>>> [email protected]> wrote: >>>> >>>>> This common exotic tree is seen with only falcategreen veinless >>>>> phyllodes whichdisguise like simple leaves. Like most Acacias this should >>>>> havebeen havingbi-pinnate leaves. Interestingly this Acacia too has >>>>> bipinnate leaves but they are seen only in sapling stage. Pinnae2, 2-5 cm, >>>>> deciduous; leafletsopposite, 6-10, sessile, oblong, 5-8 mm; petiole 5-8 >>>>> mm, >>>>> modifying and elongating to a phyllode 10-15 cm long. Scar of fallen >>>>> pinnae >>>>> can be seen at the rounded apex of the phyllode. Regards, Shrikant >>>>> Ingalhalikar >>>>> >>>> >>>> >>>> >>>> -- >>>> Dr Satish Phadke >>>> >>> >>> >>> >>> -- >>> Usha di >>> =========== >>> >>> > > > -- > Dr. Gurcharan Singh > Retired Associate Professor > SGTB Khalsa College, University of Delhi, Delhi-110007 > Res: 932 Anand Kunj, Vikas Puri, New Delhi-110018. > Phone: 011-25518297 Mob: 9810359089 > http://www.gurcharanfamily.com/ > http://people.du.ac.in/~singhg45/ > > -- Usha di ===========
