602 



LOGANIACE^. 



[Perigynous Exogens. 



Order CCXXXII. LOGANIACE^.— Loganiads. 



Logauieae, R. Brown in Flinders, (1814) ; Von Martins N. Gen. et Sp. PL 2, 133 ; Bartl. Ord. Nat. 205 ; 

 Arnott in Edinb. Eticycl. 120.— Loganiacese, Ed. Pr. ccxxiv. ; Endl. Gen. cxxxi. ; DC. Prodr. 9. 1. 

 — Potaliaceae, Brown in Tuckey, 449. m\d).—^oia\\e^, Martins N. G. et Sp. 2.91. and 133. (1828) ; 

 Royle Illustr. 269.— Strychnaceae, Blume Bijdr. 1018. (1826) ; Link. Handb. 1. 439.— Strychnese, 

 DC. Theorie ed. 1. 217. (1813),- Spigeliaceas, Martins N. G. et Sp. 2. 132. (1828) ; Ed. pr. ccxxi. ; 

 Endl. Gen. cxxxv. ; Meisner p. 2bS.—CoElostyledd, Endl. Ench. cxxxiii. 



Diagnosis. — Gentianal Exogens, mith ojjposite leaves and intervening stipules. 

 Shrubs, herbaceous plants, or trees. Leaves opposite, entire, usually ^vith stipules, 

 which adhere to the leafstalks or are combined in the form of interpetiolary sheaths. 

 Flowers racemose, corjTnbose, or solitary. Calyx valvate 

 or imbricated, inferior, 4- 5-parted. Corolla regular or 

 iiTegular, 4- 5- or 10-cleft, with valvate or convolute aesti- 

 vation. Stamens arising from the corolla, all placed upon 

 the same line, and not always symmetrical with the divisions 

 of the corolla ; pollen with 3 bands. Ovary superior, 2- 

 celled, (3, or spuriously 4-celled) ; style continuous ; stigma 

 simple ; ovules 00 or soHtary, peltate and amphitropal, or 

 ascending and anatropal. Fruit either capsular and 2- 

 celled with placentae finally becoming loose ; or drupaceous, 

 with 1- or 2-seeded stones; or berried with the seeds im- 

 mersed in pulp. Seeds sometimes winged, usually peltate ; 

 albumen fleshy or cartilaginous ; embryo small, with the 

 radicle tm*ned towards the hilum or parallel with it. 



It is not clear, from the remarks upon Logania, by Brown 

 in his Prodroimis, whether he intended to establish tliis 

 Order or not. He states that he has placed Logania at the 

 end of Geutianworts, on account of some affinity between 

 it and Exacum and IMitrasacme, and also because it 

 does not answer ill to the artificial character of that Order; 

 adding that it, however, might have a still closer connec- 

 tion with Dogbanes and with Usteria among Cinchonads.'" 

 He further points out the close relation of Geniostoma to 

 Logania, and concludes by inquiring whether those 2 

 genera do not, with Anasser, Fagrsea, and Usteria, form 

 an Order intermediate between Dogbanes and Cinchonads. 

 This view has been adopted by Von jNIartius, who however excludes Fagrsea, which he 

 places among his Potahaceae ; he founds the distinction of that Order upon the want of 

 symmetry between the parts of the calyx, corolla, and stamens, upon the aestivation of 

 the corolla being convolute, not contorted, and in the presence of stipules combined in 

 interpetiolary sheaths. Mr. Arnott remarked to me (letter, Dec. 1835) that the Order 

 may be m some respects looked upon as consistmg of Cinchonads with superior fmit. 

 More recent examination of the genera has entirely confirmed this \iew, which, how- 

 ever, does not explain with any clearness how Loganiads differ from Dogbanes. Upon 

 this subject I quote literally the words of M. Alph. De CandoUe. " I must confess that 

 I have sought in vam for a positive distinction, to which there shall be no exception, 

 between Dogbanes and Loganiads. The position of the flower with respect to the axis 

 appears to be the same, that is to say, a re-entei*ing angle of the calyx stands next the 

 axis. That of the cells of the fruit ^^•ith respect to the axis varies among Loganiads, as 

 does the aestivation of the corolla and many other characters. The grains of pollen are 

 not very different, if we rely upon the exact but scanty observations of INIr. Hassall. 

 The placentas of Dogbanes are more securely fastened to the edges of the carpellary 

 leaves, and do not separate from them when the fruit is ripe, as generally happens more 

 or less distinctly among Loganiads ; but the placenta of Sti'yclmos is exactly that of 

 Carissa. Dogbanes have a milky juice ; but exceptions to that are said to occur, as in 

 Echites for instance. Finally, the only diff'erences which I can point out are of a parti- 

 cular kind, not very satisfactory in practice, although of some value in botanical philo- 

 sophy. These reside m the natvire of the variations presented by Dogbanes and Loga- 

 niads. In the former the flowers are always isomerous m the calyx, corolla, and sta- 

 mens, and the number is never more than 5 ; in the latter the corolla and stamens have 



Fig. CCCCVII. 



Fig. CCCCVII.— Logania floribunda. 1. a corolla cut open ; 2. a pistil. 



