[Vol. 2 



124 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



of 2-6 scales or vestiges; pistil 1-celled; ovules anatropous, 

 ascending. Bambusa, Bromus, Triticum, Bouteloua, Avena, 

 Agrostis, Phalaris, Oryza, Panicum, Andropogon, Zea. 

 (Species 3545.) (Pf. 2 2 :1.) 



In the Poaceae the hypogynous, tricarpellary monocotyle- 

 dons reach their culmination, as a highly specialized side line. 

 In grasses the specialization involves plant-body, inflorescence, 

 and flowers. Their nodose, mostly hollow, elongated stems, 

 and long, narrow, tough leaves ; the spreading paniculate ar- 

 rangement of their spikelets ; and their 1-celled, tricarpellary 

 1-ovuled pistils, producing caryopsis-fruits, are some of the 

 more obvious indications of high specialization, suggesting the 

 possibility that these plants, rather than the orchids, are the 

 highest of the monocotyledons. With the Poaceae the hypo- 

 gynous monocotyledonous phylum ends. Grasses have not 

 given rise to other groups of plants. 



Sub-Class ALTERNIFOLIAE - COTYLOIDEAE. Axis 

 of the flower normally expanded into a cup, bearing on its 

 margin the perianth and stamens (or the latter may be at- 

 tached to the perianth) . The carpels are thus inferior. Flow- 

 ers from actinomorphic to zygomorphic. 



Order Hydrales. Flowers diclinous; compound tricarpel- 

 lary pistil inferior to all other parts of the flower; perianth 

 segments in each whorl alike in shape (flower regular) ; seeds 

 without endosperm. (Species about 53.) 



Family 32. Vallisneriaceae. Tape-grasses. Small aquatic 

 herbs mostly inhabiting the fresh waters of temperate cli- 

 mates. Vallisneria, Hydrocharis, Philotria. (Pf. 2 l :238.) 



Order Iridales. Compound tricarpellary pistil inferior; 

 flower-leaves in each whorl mostly alike in shape (flower reg- 

 ular, actinomorphic) ; seeds with endosperm. (Species about 

 4419.) 



Family 33. Amaryllidaceae. Amaryllises. Leaves nar- 

 row, or the blade broad, with longitudinal veins ; pistil 3-celled ; 

 ovules many; stamens 6 or 3. Amaryllis, Crinum, Narcissus, 

 Agave, Hypoxis. (Pf. 2 5 :97.) 



