Saxifragales.] 



SAXIFRAGACE^. 



567 



Order CCXIV. SAXIFRAGACE^.— Saxifrages. 



Saxifragse, Juss. Gen. 308. (1789) ; Vent. Tabl. 2, 277.— Saxifrage se, DC. and Duhy, 207. (1828).— 

 Saxifragaceae, DC. Frodr. 4. 1. ; Endl. Gen. cLxx. ; Meisner, p. 136. 



Diagnosis. — Saxifragal Exogens, with distinct styles and alteimate leaves. 



Herbaceous plants, often gi'owing in patches. Leaves either divided or entire, 

 alternate, with or without stipules. Flower-stems simple, often naked. Calyx either 

 superior or inferior, of 4 or 5 sepals, which cohere more or less at their base. Petals 



5 or 0, inserted between the lobes of the calyx. Sta- 

 mens 5-10, inserted either into the calyx, or beneath 

 the ovary ; anthers ■2-celled, bursting longitudinally. 

 Disk either hypogynous or perig}-nous, sometimes 

 nearly obsolete, sometimes annular and notched, 

 rarely consisting of 5 scales. Ovary inferior, or 

 nearly superior, usually consisting of 2 carpels, co- 

 hermg more or less by their face, but distinct and 

 diverging at the apex ; sometimes 2-celled with a 

 centi'al placenta ; sometimes 1 -celled with a double 

 placenta adhering to the sutures. Styles none. Stig- 

 mas sessile on the tips of the lobes of the ovary. 

 Fruit generally a membranous 1- or 2-celled capsule 

 with the cells divaricating when ripe. Seeds nume- 

 rous, very minute ; usually \vith long hexagonal 

 reticulations on the side of a transparent testa. Em- 

 bryo taper, in the axis of fleshy albvunen, with the 

 radicle next the hilum. 



So near is the affinity of Saxifrages and Roseworts 

 that in some cases it is difficult to 

 distinguish the Orders. Never- 

 theless they appear to represent 

 two distinct tendencies (Nixm), 

 that of Saxifrages being towards 

 the consolidation of the finiit, and 

 the formation of albumen, while 

 that of Roseworts is plainly to- 

 wards a disunion of the carpels 

 and the absorption of albumen. 

 If compared with other Orders in 

 their own Alliance, Saxifrages 

 Fig. CCCLXXXIII. will be found to differ from Loose- 



strifes and Brexiads in their dis- 

 united styles, from Cunoniads and Hydrangeads in their alternate leaves. 



More remote affinities have been indicated by authors. Thus they may be compared 

 in some respects to Cloveworts, especially to the Alsineous di\-ision of that Order ; but 

 they differ in the insertion of the stamens, placentation, situation of the embryo, and 

 otherwise. Purslanes, which may be compared with this Order, on accomit of the 

 situation of the stamens, want of stipules, and albummous seeds, differ essentially in the 

 structure of the embryo, in the want of sjnmmetry in the parts of the flower, and in 

 placentation. Currantworts correspond in the general stnicture of the flower ; but 

 differ ^videly m the ovary being completely concrete and mferior, with two parietal 

 placentae, in the seeds bemg attached to long umbihcal cords, in the albumen bcnig 

 corneous, and the embryo extremely minute. De CandoUe remarks that Saxifrages 

 approach Houseleeks, differing in having a smaller number of carpels, which are 

 partially united both with each other and the calyx, and m being destitute of glands at 

 the base of the carpels. 



Chrysosplenium is remarkable for the want of petals. 



Drummondia has the stamens 



Fig CCCLXXXIII. -Saxifraga tridactvlites. 1. its flower ; 2. a perpendicular section of it 

 section of its ovary ; 4. perpendicular section of a fruit ; 5. a seed ; 6. a section of a seed. 



