RANALES 387 



in part, in the change in place of pollen reception from proximity to 

 the ovules — on the margins of open carpels, as in species of Drimtjs 

 and Degeneria, where the tubes are very short, entering the carpel 

 chamber all along the stigmatic ridge — to the distal stigma on a style. 

 (In the gymnosperms, the pollen grain germinates in or near the ovule; 

 there is either no tube or a short one, which is not a male-cell carrier. 

 The Araucariaceae and Tsuga are notable exceptions.) 



The Winteraceae show reduction of the inflorescence from a cymose 

 cluster {Drimijs) to a solitary terminal flower (Zygogynum). This 

 series perhaps throws light on the nature of the solitary flower, which, 

 in tliis family, clearly represents the surviving member of a determinate 

 inflorescence. In the Ranales, there are many examples of solitary flowers 

 — Magnolia, Eupomatia, Hinmntandra, Zygogynum. In these genera, 

 there is little structural evidence of reduction of the solitary flower 

 from an inflorescence, but the flowers of Zygogynum have surely been 

 derived by reduction from inflorescences, and those of Eupomatia and 

 Himantandra, in their position on short shoots that may bear more than 

 one flower, suggest similar reduction. (The large size of many solitary 

 flowers is not, in itself, evidence that this type represents a primitive 

 condition; the flowers may be large because they are solitary. The 

 theory that the solitary flower is primitive is, in part, a holdover from 

 the old theory that the complex vascular sporophyte arose by the con- 

 tinued dissection and proliferation of an ancient simple sporophyte, 

 with multiplication of fertile and vegetative parts. ) 



The phylogenetic relation of primitive solitary flowers to methods of 

 pollination and to bisexual structure should be further explored. Most, 

 if not all, such flowers are bisexual and lack nectaries. In some taxa, 

 the method of pollination is unknown; in others, it is by beetles. Uni- 

 sexual flowers seem to be associated with all types of pollination except 

 the primitive type, that of beetles; this association seems to be evidence 

 in support of the primitiveness of hermaphroditism. 



Drimys is commonly considered the most primitive genus in the 

 Winteraceae, partly because of its primitive carpels, but, when all char- 

 acters are considered, Belliolum seems the most primitive. Its stamens, 

 with the pairs of sporangia laminar rather than marginal, are much the 

 most primitive in the family. (They suggest those of Himantandra.) 



LACTORroACEAE 



The monotypic genus Lactoris, a shrub of Juan Fernandez Island, 

 has been difficult to place, taxonomically; it has been placed in the 

 Magnoliaceae, Saururaceae, Winteraceae, Piperaceae, Dilleniaceae, and 

 "somewhere between the Piperaceae and the Annonaceae," but has 

 more recently been generally accepted as constituting the monotypic 



