413 

 XXXVlII. SAXIFRAGES. The Saxifrage Tribe 



Saxifragje, Jus. Gen. 308. (1789); Vent. Tabl. 2. 277. (1799).— Saxifrage*:,. Dec. atid 

 Duby, 207. (1828) ; Lindl. Synops. 66. (1829.) [Dec. Prod. 4. 1, inpart (1830.)] 



Diagnosis. Polypetalous dicotyledons, with perigynous definite stamens, 

 (2) ovaria adhering more or less to the calyx and to each other, indefinite seeds, 

 and no stipule. 



Anomalies. Parnassia has 4 parietal placentae opposite the lobes of the 

 stigma. Petals sometimes absent. Adoxa is a doubtful genus of the order, 

 \vith a berry of several cells. In Heuchera the flowers are irregular. 



Essential Character. — Calyx either superior or inferior, of 4 or 5 sepals, which cohere 

 more or less at their base. Petals 5, or none, inserted between the lobes of the calyx. Sta- 

 mens 5-10, inserted either into the calyx (perigynous), or beneath the ovarium (hypogynous) ; 

 anthers 2-celled, bursting- longitudinally. Disk either hypogynous or perigynous, sometimes 

 nearly obsolete, sometimes annular and notched, rarely consisting of 5 scales. Ovarium in- 

 ferior, or nearly superior, usually consisting of 2 carpella, cohering more or less by their faces 

 but distinct at the apex ; sometimes 2-celled with central placenta ; sometimes 1-celled with 

 parietal placentae ; rarely 4- or 5-celled. Styles none. Stigmata sessile on the tips of the lobes 

 of the ovarium. Fruit generally a membranous 1- or 2-celled capsule witli 2 bractea? ; rarely 

 a 4-celled 4-valved capsule ; sometimes a 4-celled berry. Seeds numerous, very minute ; 

 usually with long hexagonal reticulations on the side of a transparent testa. Embryo taper, 

 in the axis of a fleshy albumen, with the radicle next the hilum. — Herbaceous plants, often 



f rowing in patches. Leaves simple, either divided or entire, alternate, without stipulae. 

 lower-stems simple, often naked. 



Affinities. Most nearly allied to Rosacea?, with the herbaceous part of 

 which they agree in habit, and from which they differ in their polyspermous 

 partially concrete carpella, albuminous seeds, and want of stipule. From 

 Cunoniaceae they are divided rather by their habit, and by the want of stipulae 

 than by any thing very positive in their fructification ; the principal charateris- 

 tic feature of which consists in the more perfect concretion of the carpella. 

 Baueraceae are known by their habit, indefinite stamens, and peculiar dehiscence 

 of the anthers. To Caryophylleae their habit allies them ; but they differ in the 

 insertion of I heir stamens, their placentation, the situation of their embryo, and 

 otherwise. Portulaceae, which may be compared with them, particularly on ac- 

 count of the situation of their stamens, want of stipules, and albuminous seeds, 

 differ essentially in the structure of the embryo, in the want of symmetry in 

 the parts of the flower, and in placentation. Grossulaceae, however different 

 they are in habit, agree very much in the general structure of flowers ; they 

 differ in the ovarium being completely concrete and inferior, with two parietal 

 placentae, in the seeds being attached to long umbilical cords, in the albumen 

 being corneous, and the embryo extremely minute. Chrysosplenium and 

 Adoxa are both remarkable for want of petals ; and Parnassia, which I think, 

 upon the whole, is a genuine genus of this order, exhibits the singular anomaly 

 of placentae being opposite the lobes of the stigma, a unilocular ovarium, the 

 shell of which consists of two distinct plates connected by an intervening loose 

 substance, and a peculiar development of an hypogynous disk, which assumes 

 the form of 5 fringed scales, alternate with the stamens, and of a highly curious 

 structure. Adoxa, which has a berry of several cells, and which is always 

 referred here, appears to me far more anomalous than Parnassia. Drummon- 

 dia has the stamens equal in number to the petals and opposite them, thus indi- 

 cating some analogy with the monopetalous Primulaceee. 



Geography. Little elegant herbaceous plants, usually with white flowers, 

 cesspitose leaves, and glandular stems ; some of the species have yellow flowers, 

 others have red, but none blue. They are natives of mountainous tractsin Europe 

 and the northern parts of the world, frequently forming the chief beauty of that 

 rich turf which is found near the snow in high Alpine stations. Some grow on 

 rocks and old walls, and in hedge-rows, or near rivulets, or in groves. 



