oh forgot the URL: It is at : http://www.uq.edu.au/_School_Science_Lessons/9.70.1.GIF thanks Usha di
On Sun, Mar 25, 2012 at 5:03 PM, ushadi Micromini <[email protected] > wrote: > 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 > =========== > > -- Usha di ===========
