831 



XXX. AROIDE^. 



Pistia Slratiotcs, 

 Inflorescence. 



Pistia Slraliotes. 

 Inflorescence cut vertically (mag.). 



Pistia. 

 Orthotropous ovule cut verti- 

 cally, and. the hairs accom- 

 panying the placenta (mag.). 



Pistia. 



Ovary cut vertically 



(mag.). 



Pistia. 



Portion of androecium 



(mag.). 



Pistia. 

 Embryo (mag.). 



Orontium aquaticum. 



Ovai-y cut vertically 



(mag.). 



Pistia, 

 Seed, entire and cut vertically (mag.)- 



Richardia. 

 Transverse section of 

 lower part of ovary. 



Riehardia. 

 Transverse section of upper part of ovary. 



Orontium aquaticum. 



Flower seen in front 



(mag.). 



Orontium. 

 Stamen (mag.). 



Flowers monoecious, or more rarely dioecious, or 5 y inserted on a simple spadix, 

 furnished with a spathe, with or without a perianth. Ovaet l-several-celled ; ovules 

 basilar or parietal, erect, ascending or pendulous, orthotropous, campylotropous or ana- 

 tropous. Fruit a terry. Seed albuminous, or very rarely exalbuminous. Embryo 

 axile. — Stemless or caulescent plants. Leaves radical or alternate, blade dilated or 

 linear, nerves prominent, reticulate. 



Usually herbaceous plants, with colourless or milky sap, perennial, sometimes 

 with a rhizome or tubers, and 'then stemless 5 sometimes caulescent, with straight, 

 branched and arborescent stems marked with petiolar scars, sometimes sarmentose, 

 or climbing by means of adventitious roots; sometimes viviparous [Remusatia vivi- 

 para), very rarely floating {Pistia). Leaves sometimes solitary, usually terminating 

 an epigeal rhizome or stem, alternate, glabrous ; petioles sheathing at the base ; blade 

 usually dilated, strongly palmi-pedati-pelti-nerved, cordate or hastate, entire or 

 variously cut, sometimes perforated or bulbilliferous, vernation convolute. Scape or 

 STEM terminated by a spadix. Spathe monophyllous, variously involute, persistent 

 or deciduous. Spadix simple, springing from the axil of the spathe, free, or adhering 

 to its midrib, sessile or stipitate, entirely covered with flowers, or terminated by a 

 sterile appendage, very various in form. Flowers usually imperfect, rarely g, 

 sessile on the spadix, the ? usually below, the $ above, contiguous, or separated by a 



