CLASSIFICATION OP MONOCOTYLEDONS 235 



VII. Fablnales.* — The eleven families of this alliance are 

 Flagellariaceae, Restionaceae, Centrolepidaceae, Mayacaceae, 

 Xyridaceae, Eriocanlaceae, Rapateaeeae, Bromeliaceae, Com- 

 melinaceae, Pontederiaceae, and Philydraceae, together contain- 

 ing a little more than 2,000 species. The large families are 

 Bromeliaceae with over 900 species, Eriocaulaceae with 460, 

 Commelinaceae with more than 300, and Restionaceae with 

 nearly 250. The chief character that holds these diverse fami- 

 lies together and separates them from the Liliales is the thin- 

 walled endosperm rich in starch, whose cells become easily 

 broken up and dissociated, resulting in a " mealy " or " crum- 

 bly " endosperm. 



From the evolutionary standpoint the following facts are of 

 importance: for the most part the forms are grass-like herbs, 

 with all habits from aquatic to xerophytie and epiphytic ; they 

 are mostly bracteate forms, the upper bracts showing a decided 

 tendency to ensheath the inflorescence ; thev are mostlv ane- 

 mophilous, but some forms have a perianth adapted to ento- 

 mophily ; the perianth ranges from scarious to petaloid, from 

 undifferentiated to a distinct calyx and corolla, from polypetaly 

 to sympetaly ; the flowers are syncarpous and, with the excep- 

 tion of a few r Bromelias, hypogynous. 



Such evidence indicates a relatively primitive cyclic alli- 

 ance with many characters recalling the spiral forms, the 

 bract-protection and anemophily not being definitely replaced 

 by a highly developed perianth and entomophilv. The origin 

 of the series is of course obscure, but the evidence seems to 

 favor the Glumales as the original stock. As illustrating the 

 construction of a natural sequence of families, those of this 

 alliance may be used as follows: 



The Flagellariaceae, Restionaceae, and Centrolepidaceae, 

 belonging to the oriental tropics chiefly of the Southern Hemi- 

 sphere, have a bracteate undifferentiated perianth and are ane- 

 niuphilous, in habit and general character resembling the Spiral 

 series. 



The Mayacaceae, Xyridaceae, and Eriocanlaceae have a dif- 

 ferentiated calyx and corolla, and orthotropus ovules with very 

 small embryos. These three famili* -. together with Restiona- 



* Farixosae of Engler. 



