TRANSACTIONS OF SECTION K. 813 



scale: Schleiden, Baillon, Strasburger, Masters, regard ic us an n.rud stractiire; 

 Sachs and Eichler as a liyular iilacenta ; Delpino and Penzig as the txoo lateral 

 lohes of the bract ; R. Brown as a carpel; Van Tieghem as^ the first ami imli/ leaf 

 of an axillary bud; Braun, Caspary, Von Mohl, Steuzel, Celakovsky, and several 

 others as homologous with the two first leaves (or their ovular i-e})re8e7itatives) of 

 an axillari) bud. Celakovsky holds further that throughout Coniferse the ovule 

 has two integuments; in Abietinete, Taxodinese, Cupressinete, Araucarieae, the 

 outer integument is normally proliferated as a seminiferous scale, this being the 

 exact counterpart of certain stages in the proliferation of the ovule of angiosperuis ; 

 in Podocarpus, Cephalota.rus, Torrei/a, and Ginkgo it is the outer fleshy coat of the 

 seed ; in Taxus, Microcachri/s, Dacrydium, it is the fleshy aril. 



Cycadacece, 



Most authors regard ovule as possessing a single integument. Celakovsky 

 considers it, along with Cephalotaxus, &c., as being holochlamydeous, i.e., having 

 the two integuments intimately united, the outer fleshy and the inner woody. 



Filicinecs. 

 Homosjiorcnis Leptosj)orangiates. 



Celakovsky's view here maintained that soriferous segment of pinnule, bearing 

 as a rule sporangia on its lower (dorsal) surface, is the homologue of the outer 

 integument of the ovule in Angiosperms, and indusium that of inner integument. 

 Evolutionary series can be traced beginning with : — -(1) Thyrsopteris and Hymeno- 

 phylldcefB where indusium, enclosing sorus, is terminal to leaf-segment = most 

 primitive type. (2) Dicksonia, Gibotium, Davallia, Lygodiuni : the indusium, 

 along with sorus, is displaced on to lower surface by outgrowth of leaf-segment. 

 (3) Cystopteris, Cyathea, &c. : sorus arises from earliest stage onward on lower 

 surface. (4) Polypodium, Pterifi cretica : indusium completely disappeared ; all 

 these conditions have their homologues in stages of the proliferated ovule. 



Heterosporovs Leptosporangiates. 



In Salviniaceae the fruit is equivalent to an ovule with one integument ; 

 indusium = inner integument, and leaf-lobe bearing sorus is probably homologous 

 with outer integument. Striking resemblance between monangic sorus of Azolla 

 and an ovule. In Marsiliaceae fruit = compound fruit of Salviniacoaj. In Pilu- 

 laria it is homologous with the pinnately 4-follolate leaf of Marsilia ; in Marsilia 

 with a pinnately multifoliolate leaf. Outer Avail of sporocarp is homologous with 

 upper surface of outer integument of ovule ; indusium, enclosing many sori, with 

 inner integument of latter. 



In most Filiciueae sorus is polyangic ; in Schizseacere and Azolla it is monangic, 

 as in most Phanerogams. In latter poiysorous character occurs abnormally in 

 Hesperis and normally in Cupressus, where outer integument bears on its dorsal 

 purl'ace several inner integuments containing nucelli. 



Lycopodiacece. 



Isoetes: View of Celakovski^ held that velum is equivalent to indusium of 

 Ferns, and ligule to the soriferous leaf-segment of latter ; hence sporangium along 

 •with these two organs = ovule with its two integuments. 



Lepidocarpon : ' Integument' is probably equivalent to velum of Isoetes, but 

 better developed, and thus to inner integument of ovule. Ligule is regarded as 

 really situated outside the 'integument,' the latter being open at the distal end. 



In other genera either velum or both this and ligule have either quite aborted 

 or never been developed, which is probably result of eflicient protection of 

 sporangia by peltate ends of sporophylls, as in Lepidodendron and Spencerites, 



In EquisetacesB peltate sporophylls afford necessary protection. 



9t On Ancient and Modern Seeds. By Professor F. W. Oliver, D.Sc 



