CONTENTS. V 



Page. 

 XVIII. — The Dihk, the Citru.s, the Rlta, and thk P.koma 



MOUTAN - - - - - - - -331 



Definition and morphological position of the disk- -The 

 morphological po>ition of the oiauge-peel. 



View (a). — That it is the outer lamina of the pn]p-carpels — 

 Objections to this view. 



View (k). — That it is a distinct whorl of abortive carpels, or 

 other phrilous members, independent of the pulp — Facts 

 supporting this view — Fibro-vascuh\r bundles of A^an 

 Tieghem not inimical to this view — Too much stress laid on 

 the supposed significance of fibro-vascular bundles — 

 Immense seaweeds can develop without any trace of fibro- 

 vascular tissue. 



View (jc). — That the peel is a continuation of the stem-bark, 

 this view explained by diagrams. 



It finally brings us round to view (k) — The bark does not 

 receive special fibro-vascular bundles — The disk and peel 

 according to Payer- -Atrophy of parts leads to atrophy of 

 vessels which nourish them —Absence of vessels cannot be 

 accepted as indication that the peel is )iot of a phyllous nature 

 — Homology' of the orange-peel with the disk of other 

 Rutacese-- Drawing of abnormal Citrus in " Gard. Chrou." 

 proves that Dr. Bonavia's view of the orange-peel is the 

 right interpretation — The sheath enveloping the carpels of 

 Paonia Moutan is homologous with the orange-peel — Obser- 

 vations on the doubling of the Pseony, with depauperation 

 of the carpel sheath — PcDony sheath, the homologue of the 

 staminal tube of the Malvaceae — Further evidence to prove 

 that the Citrus disk is a whorl of suppressed stamens — 

 Identity of the stamen filament c<f the Citrus M-ith its peel — 

 Final disproof that the peel consists of the outer lamina? of 

 the carpels — Identity of peel oil-glands with the juice vesicles 

 of the pulp, according to 0. Penzig- -Identity of these with 

 the dermal oil-glands of Dictariinuxfraxinella, and with the 

 reprodui:tive hairs of Ci/ntopoJUi hurhaUt. 



XI X'. — Gr.xEUAL CoN'CLrsioics ----- 3G1 



A Z 



