1916] 



BESSEY PHYLOGENETIC TAXONOMY 121 



leaves; flowers monoecious in dense globose heads. Spar- 

 ganium. (Pf. 2 1 :192.) 



Family 7. Pandanaceae. Screw-pines. Shrubs or trees 



with spirally crowded, narrow, stiff leaves on the ends of the 



branches ; pistil 1-celled ; ovules one or many. Pandanus. (Pf . 

 2 1 :186.) 



Family 8. Aponogetonaceae. Aquatic plants with petioled, 

 oblong, translucent leaves, with convergent veins; flowers 

 small, spicate. Aponogeton. (Pf. 2 1 :218.) 



Family 9. Potamogetonaceae. River-weeds. Aquatic or 



paludose herbs with mostly alternate stem-leaves; flowers 



mostly small and inconspicuous; perianth none, or of 1-6 



leaves in 1 or 2 whorls. Potamogeton, Zostera, Zannichellia. 

 (Pf. 2i:194.) 



Order Liliales. Carpels united (usually 3), forming a com- 

 pound pistil, superior; perianth (usually of 6 parts) in two 

 similar whorls, delicate and corolla-like; endosperm copious. 

 (Species about 3370.) 



Family 10. Liliaceae. The Lilies. Pistil mostly 3-celled; 

 stamens 6 ; perianth of two similar whorls, each of three sim- 

 ilar leaves. Lilium, Erythronium, Tulipa, Yucca, Asparagus, 

 Allium. (Pf. 2 5 :10.) 



Family 11. Stemonaceae. Pistil 1-celled; stamens 4; peri- 

 anth of two similar whorls, each of two similar leaves. Stem- 

 ona, Croomia. (Pf. 2 5 :8.) 



Family 12. Pontederiaceae. Aquatic herbs with 3 or 1- 



celled pistil; stamens 6 or 3; perianth of two similar whorls, 

 each of three similar or dissimilar leaves. Pontederia, Heter- 



anthera. (Pf. 2 4 :70.) 



Family 13. Cyanastraceae. Tropical African rhizomatous 

 plants. Cyanastrum. (Syllabus, 141.) * 



Family 14. Philydraceae. Pistil 3-celled; stamen 1; peri- 

 anth of two similar whorls, each of two dissimilar leaves. 

 Philydrium. (Pf. 2 4 :75.) 



1 "Syllabus" has reference to Engler and Gilg's 'Syllabus der Pflanzenfamilien,' 

 and the numbers following refer to pages of this publication. 



