428 A CENTURY OF PROGRESS IN THE NATURAL SCIENCES 



earpous gynoecia, as fundamental, and parietal, free-central, and basal as de- 

 rivative. Winkler (1939) held similar views, iDut pointed out that false septa 

 might arise almost anj'where; in Malvales C. V. Eao (1952) postulates multipli- 

 cation of carpels by "chorisis," while Edlin thought the free carpels secondarily 

 derived from a syncarpous condition. Free-central placentation — one of the 

 chief props of "stachyspory" — is now generally conceded to be a reduction prod- 

 uct from axile placentation in both Caryophyllales (Laubengayer, Thomson) 

 and Primulales (Dickson, Douglas), constituting a bond of affinity between the 

 two groups. Gunderson (1939a, 1939b, 1941, 1943), apparently chiefly on onto- 

 genetic grounds, thought that carpels united first by their margins, and hence 

 that parietal placentation is primitive. Axile placentation, achieved by exten- 

 sion of the placentae to, and their union at, the center of the gynoecium, he 

 regarded as an evolutionary advance, providing the ovules with better nourish- 

 ment and protection. He also suggested that one or few ovules with basal pla- 

 centation is a condition associated w^ith anemophily, that numerous ovules located 

 parietally indicate entomophily, and that both conditions may be primitive. 

 Perhaps in Gentianaceae (Lindsey) and Begoniaceae (Gauthier) parietal pla- 

 centation preceded axile and in Cactaceae (Buxbaum, 1944) free-central. Troll 

 1933a, 1933b) and Leinfellner (1950) drew a sharp distinction between a 

 "syncarpous" ("eusyncarpous") — multilocular with axile placentation — and a 

 "paracarpous" ("hemisyncarpous") — unilocular with parietal or free-central 

 placentation — gynoecium and found them to be quite different in their vertical 

 organization. However, Eames avers that "lines between types of placentation 

 do not exist" (1951, p. 23). Puri is uncertain as to the origin of laminar placen- 

 tation, but many have found it important in linking the monocotyledonous Alis- 

 matales with Nymphaeaceae, and Junell (1934) regarded it as the placentation 

 type basic to Viticoideae (Verbenaceae) and all Labiatae, including those mem- 

 bers of the latter family which have dry nutlets and a gynobasic style. Blaser 

 (1941) distinguished Cyperaeeae from Gramineae by the fact that, while both 

 have solitary basal ovules, those of the former are derived from free-central 

 placentation, those of the latter from parietal. It may be significant that in 

 Ranales incipient syncarpy has arisen in at least three ways (Bailey and Swamy, 

 1951), and one is inclined to agree with Puri that "it is apparent that there is 

 no uniform pattern followed and evolution seems to have progressed along sev- 

 eral lines" (1952b, p. 625). 



D. Nectaries: Because the angiosperms are believed by many to have been 

 primitively insect-pollinated, it has been suggested that they were also basically 

 honey producers (Nicotra; Werth, 1923). As early as 1913, Porsch was calling 

 attention to the possible utility of nectaries as indicators of phylogenetic rela- 

 tionship, but it was Brown (1938) who really took this suggestion seriously. 

 Brown warned that nectaries appear to have arisen independently in different 

 lines of affinity, and that they have then undergone modifications characteristic 

 of the various groups. Basing his groupings on the Hutchinson (1926) system 

 and emphasizing woody versus herbaceous lines, he recognized five principal nec- 

 tarine plexi: (1) septal, or ovarial glands, confined to monocotyledons, in which 

 he thought palms might be primitive; (2) gynoecial, androecial, or toral disk 

 nectaries, centering about Theales or Bixales (Guttiferales), and leading in sev- 

 eral directions — through the Sympetalae to Lamiales, to herbaceous Caryophyl- 



