Gentianales.] 



APOCYNACE^. 



599 



Order CCXXXI. APOCYNACE^.— Dogbanes. 



Apocyneae, Juss. Gen. 143. (1789) in part; R. Bromi Prodr. 465. (1810) ; Royle's Illustrations, 269.— 

 ApocjTiaceae, Ed. pr. ccxxii. (1836) ; Endl. Gen. cxxxii. ; DC. Prodr. 8. 317. ; Alph. DC. in 

 Ann. Sc. 3 ser. 1. 235.— Contortae, Linn.— Y'mcede, DC. and Duby Bot. Gall. 342. (1828), a § of 

 Apocyneae. 



Diagnosis. — Gentianal Exogens, with no stipules, and the stigmas collected into a massive 

 head, expanded at the base in the form of a Hng or membrane, and contracted in the 

 middle. 



Trees or shrubs, usually milky. Leaves opposite, sometimes whorled, seldom scat- 

 tered, quite entire, often having cilise or glands upon or between the petioles, but with 

 no stipules properly so called. Inflores- 

 cence tending to cor^Tubose. Calyx free, 

 5-parted, persistent. Corolla monopeta- 

 lous, often having scales in its throat, 

 hypogynous, regular, 5-lobed, with con- 

 torted aestivation, deciduous. Stamens 5, 

 arising from the corolla, with whose seg- 

 ments they are alternate ; filaments distinct; 

 anthers adhering firmly to the stigma, 

 2-celIed, opening lengthwise ; pollen gra- 

 nular, globose, or 3-lobed, immediately 

 applied to the stigma. Ovaries 2, or 1- 

 2-celled, polyspermous ; styles 2 or 1 ; 

 stigma 1, contracted in the middle and 

 assuming much the appearance of an hour- 

 glass ; o\niles usually 00, amphitropal, or 

 anatropaL Fruit a folHcle, capsule, or 

 drupe, or berry, double or single. Seeds 

 with fleshy or cartilaginous albumen, usu- 

 ally pendulous ; occasionally without albu- 

 men ; testa simple ; embryo foHaceous ; 

 plumule inconspicuous ; radicle tui'ned 

 towards the liilum. 



The singular stigma, more easy to repre- 

 sent by a drawing than to describe, is one 

 of the best indications of this Order ; it is 

 generally expanded at the base into a 

 circular membrane or inverted cup, and 

 is contracted somewhere near the middle. 

 Bearing this in mind, the Loganiads, Gentianworts, and Cinchonads are distinguished 

 with precision. In addition to this, the ovary is usually formed by the mere approxi- 

 mation of two carpels having httle or no adhesion except at the point and along 

 the styles and stigmas. In this respect it corresponds with Asclepiads, the economy 

 of whose stamens, pollen, stigma, and seeds is in general such that the nature of the 

 ovary seems an indication of analogy instead of affinity, as is commonly believed. An 

 elaborate account of the pecuHarities and affinities of the Order has been di*avvn up by 

 M. Alph. De Candolle in the place above quoted, to which the reader is referred for 

 further information. 



The species are prmcipally tropical, throwing out a few representatives only, such as 

 Vmca and Apocynum, into northern countries. They appear to be most abundant in 

 the hot parts of Asia, somewhat less common m the tropics of America, and by no 

 means abundant in Africa. 



Dogbanes are for the most part plants of considerable beauty, with large, showy, 

 gay -coloured flowers. They are, however, in many cases venomous, and very generally 

 to be suspected, although in some cases they are used medicinally, and in others have 

 an eatable fruit. Among the true poisons Tanghinia venenifcra stands foremost. The 

 kernel of the fruit, although not larger than an Almond, is sufficient to destroy twenty 

 people. It was used in Madagascar as an ordeal, l)ut the practice is now discontinued. 



Fig. CCCCVI.— Vinca minor. 1. corolla opened ; 2. style and stigma ; 3. perpendicular section of the 

 double ovary ; 4. section of a seed. — Gmrtncr. 



Fig. CCCCVI. 



