SAXIFRAGIN.E. 451 



50 genera ; about 1,000 species. Several species are cultivated in our con- 

 servatories for the sake of the flowers, which are beautifully coloured and 

 arranged in crowded inflorescences. Protandrous. It is doubtful whether they 

 were existent in Europe in the Tertiary Period. The true systematic position 

 of the order is doubtful. They are related to the Leguininosaa and Rosiflorse, 

 but more closely no doubt to the two preceding orders. 



Family 19. Saxifraginae. 



The flower is generally perfect, regular and polypetalons, 

 usually perigynous or epigynous, encyclic and 5-merous ; most fre- 

 quently So, P5, A5 + 5 or 5 + and G2-5, but other numbers 

 are found, especially 4 ; the flowers are very frequently obdi- 

 plostemonous. The calyx is sometimes large and the corolla 

 small ; the carpels in some are entirely free, in others more or 

 less united. Endosperm is found in the majority. The hypogynous 

 forms approach the Cistifloras, the others the following families, especially 

 the Rosiflorae. This family is not, upon the whole, so well defined and natural 

 as most of the others. The Saxifragaceae proper, approach very near to the 

 Rosaceae, especially Spircca, and form a transition to it,. The forms with op- 

 posite leaves, as Philadelphia, etc., approach the Myrtifloras, just as the Escal- 

 loniaa appear to be closely allied to Bicornes, especially VacciniacecB. Finally 

 through Pittosporacetf , they pass over to the Frangulinae. The family ter- 

 minates in very reduced forms, on the one hand in the arborescent orders with 

 crowded inflorescences, on the other perhaps in the very remarkable order 

 Podoxteiiiac.etc. 



Order 1. Crassulaceae. Nearly all are herbs or small shrubs 

 with round, succulent branches and scattered, fleshy, often more 

 or less round leaves, which are very rarely incised, and never 

 have stipules. The flowers are generally 

 borne in dichasia or unipared scorpioid e 



cymes, which again may be arranged in 

 racemes, umbels, etc. ; they are regular, 

 5 , hypogynous or peryginous, and most 

 frequently have free sepals and petals 

 (gamopetalous corollas with sessile sta- 

 mens are found in Cotyledon, Uryophylhim, 

 Echeveria, and others); the floral formula 

 is Sn, Pn, An + n, Gn, where n may have FlG< 487 ;~ Dia * m of ; ft 



J 6-meroua flower (Sedum IDS- 



very different values, partly depending pnnicum) -. w branch of scor- 



upon the size of the flower (e.g. 4-7 in pioid cyme in the axil of the 



t)rrt.ctGol(^ Q 



Sedum, Fig. 487 ; 6-30 in Sempervivum ; 



4 in Rhodiola, BryophyUum, and Kalanclioe ; 5 in Echeveria, Um- 

 bilicus, Cotyledon). The carpels are/ree and are placed opposite the 

 petals (Fig. 487). Fruit a syncarp composed of follicles containing 



