Saxifragales.] 



HYDRANGEACEiE. 



569 



Order CCXV. HYDRANGEACE^.— Hydrangeads. 



Hydratgeae and Bauereae, DC. Prodr, 3. 13. (1830) ; § § of Saxifragacese, Endl. Gen. p. 820.— Ilydran- 

 geaceae, Siehold and Zuccarini, Fl. Jap. 1. 102. m notis (1835). ?— Baueraceae, Ed. vr Ao 40 

 asm; Martius Conspectus, No. 226. f • ■ ^. 



Diagnosis. — Saxifragal Exogens, with distinct styles, and opposite leaves without stipides. 



Shrubs with perfectly opposite simple leaves, smooth or downy, with simple hairs ; 

 destitute of stipules ; sometimes creeping and rooting Uke Ivy. Flowers usually in cymes, 

 those in the centre , the marginal 

 often sterile and furnished with 

 larger petals than the others. Calyx 

 adhering more or less to the ovary, 

 4- 6-toothed. Petals 4- 6, inserted 

 within the edge of the calyx, 

 deciduous. Stamens 8- 12 in 2 rows, 

 or 00, inserted in the orifice of the 

 calyx, distinct, deciduous. Anthers 

 oblong or roundish ; pollen with 3 

 longitudinal farrows. Ovary more 

 or less adherent to the calyx, con- 

 sisting of from 2 to 5 carpels, 

 adliering by theu' sides and forming 

 an incompletely 2- 5-celled ca\dty ; 

 placentae distinct from each other, 

 but touchingjwith many anatropal as- 

 cending or horizontal ovules; styles 

 as many as the carpels, perfectly 

 distinct, diverging, with simple reni- 

 form stigmas. Fruit a capsule 

 crowned by the permanent diverging 

 styles, 2- 5-celled, %vith a number of 

 minute seeds, sometimes indefinite, 

 sometimes few, in consequence of 

 the abortion of a part of the ovules. 

 Testa thin, membranous, netted, oc- 

 casionally expanded into a wing. 

 Embryo orthotropal, in the axis of 

 a small quantity of fleshy albumen. 



The relationship between Hy- 

 drangeads and Saxifrages is ad- 

 mitted by all systematists, who have 

 in general united them in the same 

 Order. The opposite leaves of the former, the tendency to a polygamous structure evmced 

 in their radiant male flowers, and the genei*al increase of carpels beyond two, seem to 

 offer good groimds for separatuig them. Like Saxifrages, their styles are almost always 

 distinct and very often divergent. In some the ovary is entirely adlierent to the calyx ; 

 in others, as Hydrangea virens, it is more than half separated. Schizophragma, a 

 curious Japanese genus, has the styles rniited, and thus furnishes a transition to Capri- 

 foils on the one hand, and to Henslovia on the other. Siebold and Zuccarini place 

 Deutzia here, and it may be regarded as a genus bringing the Philadelphs in contact. 

 Bauera is anomalous in its whorled exstipulate leaves and porous anthers, but can 

 hardly be separated, unless it be referred to Cimoniads, upon the supposition of Don, 

 that its lateral leaves are modified stipules. 



Siebold and Zuccarini remark that out of the species hitherto discovered, all of which 

 inhabit the temperate parts of Asia and America, two only belong to the Southern he- 

 misphere, and 23, or about one half, to China and Japan. These authors do not, how- 

 ever, include Bauera, but they admit Deutzia. The speaies arc found naturally in 

 moist, shady places. 



Fig. CCCLXXXIV. 



Fig. CCCLXXXIV.— 1. Hydrangea virens and its flower. 

 3. its seed; 4. a section of it. 



-Siebold ; 2. seed-vessel of IT. hortensis ; 



