250 MORPHOLOGY OF ANGIOSPERMS 



tropical, are regarded as one line, characterized by an oily en- 

 dosperm; and among them such primitive characters as the 

 spiral arrangement and indefinite number of floral members 

 occur, and even apocarpy (Ochnaceae). Another line includes 

 the Elatinaceae to the Frankeniaceae, chiefly a temperate group 

 characterized by a starchy endosperm. The Fouquieraceae are 

 regarded as independent of the last line on account of their 

 sympetaly and oily endosperm. The Cistaceae and Bixaceae 

 also form an independent line with starchy endosperm. The 

 Cochlospermaceae and Koeberliniaceae are also regarded as 

 independent and much resemble the Capparidaceae among the 

 Khoedales. The families from Canellaceae to Achariaceae form 

 another line, all characterized by oily endosperm, starting with 

 completely cyclic flowers, and leading to such special develop- 

 ments as a strong tubular development of the receptacle and 

 even sympetaly (Achariaceae). Closely related to this line are 

 the Caricaceae, with sympetalous corollas, but distinguished by 

 their stamens and latex system. The last four families (Loasa- 

 ceae to Ancistrocladaceae) are epigynous, but each one seems to 

 be a peculiar and isolated type of development. This complex 

 alliance is a good illustration of divergent lines of development 

 within one general circle of affinity, and at the same time of a 

 gradual increase in floral complexity. 



XXIV. OPUNTIALES. This includes the single family 

 Cactaceae, with about 1,000 species. This characteristic Amer- 

 ican family presents a strange mixture of primitive and ad- 

 vanced characters in the structure of the flower. The spiral 

 arrangement and indefinite repetition of floral members are 

 often as primitive as in the Nymphaeaceae, with which region 

 of the Ranales the alliance may be connected. The tubular 

 receptacle, however, enclosing the constantly syncarpous pistil 

 relates the group to the Parietales. 



XXV. MYRTALES. This includes the Geissolomaceae, Pe- 

 naeaceae, Oliniaceae, Thymelaeaceae, Elaeagnaceae, Lythra- 

 ceae, Sonneratiaceae (Blattiaceae), Punicaceae, Lecythidaceae, 

 Rhizophoraceae, Combretaceae, Myrtaceae, Melastomataceae, 

 Onagraceae, Hydrocaryaceae, Haloraghidaceae, and Cynomo- 

 riaceae, together containing about 7,180 species, the large fami- 

 lies being Melastomataceae with 2,750 species, Myrtaceae with 

 2,565, Onagraceae with 465, Thymelaeaceae with 395, and 



