Don wrote:>> the petals of the rose were rather transformed..transformed stipules..than complete leaves.
Hmmm. I would think that this question has already been answered by the folks who study inflorescence. Does anybody here from academia know if petals and stipules are the same bird?
Proceedings of the Academy of Natural Sciences of Philadelphia 41: 53-66 (1889)
Contributions to the Life Histories of Plants. No. IV
Clear as it is to the mind that when carefully traced, the petal of a rose is formed of an enlarged stipule, and not of a fully planned leaf, the positive evidence is not furnished as freely as in the case of the sepal, but specimens of Rosa humilis, sent to me in 1883 by Miss Jennie E. Whiteside, of Harmonsburg, Pennsylvania, give an excellent illustration. This form has been figured and described by Mr. Sereno Watson in the Garden and Forest for February 13th, 1889 as Rosa humilis, var triloba. The trilobed petal is simply a case in which the usual stipule forming the petal of the rose, has again had its normal growth accelerated towards a perfect leaf. The central lobe is in fact no more than a dilated petiole, with the stipule represented by the two lateral lobes, in its normal position at its base. The same process from the total arrestation of petiole and leaf blade to the abnormal dilation of the stipule to form the petal, can be traced in magnolia, as made plain in the paper above cited.
https://books.google.com/books?id=dHkOA ... &q&f=false
Annual Report of the Board of Regents of the Smithsonian Institution for the Year ending June 30, 1896 pp. 421-422
The biologic relations between plants and ants
Associate of the Faculty of Medicine at Paris
Along the edges of the leaves of the Rosa Banksiae are found perifoliary nectaries that attract great numbers of a large black ant (Camponotus pubescens). The presence of these ants preserves the rose from the attacks of a hymenopterous insect (Hylotoma rosae). We owe an interesting experiment upon this subject to Beccari. On a branch of Rosa Banksiae attacked by ants he placed a branch of another rose bush attacked by the larvae of Hylotoma. Incommoded by the ants, these larvae took refuge upon the youngest buds, unprovided as yet with nectaries, and consequently not visited by ants. It is to be remarked that the Banks rosebushes, which are rarely or never attacked by Hylotomas, are destitute of prickles. We may probably admit that there is a correlation between the presence on plants of thorns or prickles and that of leaf-eating insects. Is it not due to the protection given by ants and other sting-bearing hymenoptera that the Banks rosebushes attain the great age that some of them are known to do? We may cite as an instance one of these bushes planted in 1803 by Bopland in the garden of the marine hospital at Toulon, which has a stem a meter in diameter at the base and bears each year from fifty to sixty thousand flowers.
The leaves of peach, apricot, and cherry trees may, as there is reason to suppose, be derived from compound leaves. The nectaries which they carry on the petioles should then have the significance of aborted leaflets filled with sweet stores.
https://books.google.com/books?id=a8DaQ ... &q&f=false
The Biology of Nectaries, p. 193 (1983)
Extrafloral Nectaries: Their Structure and Distribution
Thomas S. Elias
One or more, often paired nectaries of the Flach or Hoch type are present at the distal part of the petiole in many species of Prunus and some species of Rosa. In addition, some members of this genus have branched stipules which are nectariferous.
https://books.google.com/books?id=9ULQh ... ry&f=false
Bullettino dell'Orto botanico della R. Università di Napoli, Volume 1 (1899)
Piante Formicarie (Seguito)
Prof. Federico Delpino
Rosa bracteata. -- L’inspezione attenta del diportarsi delle formiche mi ha rivelato la esistenza dei minuscoli nettarii di questa specie. Invero i suoi vigorosi rampolli scarseggiano di spine, e mancano dei soliti peli glandolosi allontanatori delle formiche. Le foglioline sono serrate, e l’apice dei denti, a vece di essere occupato, come nelle altre specie di rose, da collofori, porta un piccolo nettario mellifluo. Questa secrezione, ch'è poco diuturna, riscontrandosi soltanto nelle foglie giovani, adesca un certo numero di formiche, che dimorano verso le sommità vegetative dei rampolli medesimi, e passano lentamente dalle foglioline d‘ una foglia a quelle di un'altra, visitando metodicamente l‘apice dei denti fogliari. La quantità del miele emanato è di gran lunga inferiore a quella della Rosa Banksiae; ma è anche proporzionalmente minore il numero e la statura delle formiche accorrenti. Prendendo la media di molte osservazioni ho rilevato nella sommità di ogni rampollo la presenza o di una sola formica di una mezzana statura, o di quattro o cinque di piccola.
È notevole cosi in questa che nella Rosa Banksiae la mancanza dei soliti peli glandulari; i quali veramente qui sarebbero un contro senso, perocchè sono allontanatori delle formiche.
https://books.google.com/books?id=mwI0A ... &q&f=false