Biological Papers. 107 



599. Luzula campestris DeCandolle. Wood-rush. Woodlands, S. E K. ; 

 1 -4 dm ; common. April. (S) 



600. Luzula bulbosa (Wood). Bulbous Wood-rush. Woods, near streams, 

 S. E. K.; 2-5 dm. ; occasional. April. (S) 



Subclass B. SPADICIFLOR^. Jacks-in-Pulpit, 

 Spadix-flowered Monocotyi.s. 



Flowers crowded upon a fleshy spadix, or in a dense continuous or inter- 

 rupted spike, or in an ovoid or globose head, often subtended by a foliaceous 

 spathe, sometimes colored white or other than green. Perianth none, ( r 

 what little there may be consisting of a few hairs or hyaline or chaffy scales 

 free from the ovulary. Andrcecium normally of two to twelve stamens, in 

 one or more whorls, three or fewer in each whorl, usually with very short 

 filaments or none at all, and with bisporangiate anthers opening by pores 

 or slits. Pollination anemophilous and hydrophilous. Gynoecium of numer- 

 ous stipitate or sessile unilocular carpels, each ovulary with a single anat- 

 ropous ovule. 



Order XIX. ARALES. The Arads. 



Inflorescence normally spadiceous and spathaceous. Flowers without a 

 perianth, or perianth reduced to mere chaffy scales, but with the entire 

 spadix protected by a spathe. Stamens two to ten, filaments short. Pistil 

 tricarpellary, the ovulary in each carpel with two or more ovules. 



Family 38. Lemnace-e. Duckweed Family. 

 Minute stemless and leafless floating herbs, reduced to mere thallus-like 

 fronds, which multiply all summer by proliferous offsets from the edge or 

 upper surface of the fronds. On approach of winter blossoming takes 

 place, and hypnospermous seeds are formed, which sink to the bottom till 

 warm weather next year; then they come to the surface, and multiply as 

 before. Inflorescence reduced to three flowers, two of a single minute 

 stamen having an anther with two to four sporanges each, the third an ex- 

 ceedingly simple carpel, the whole subtended by a minute scale-like spathe 

 in a pit. Ovules two to several. Fruit a utricle containing a single seed 

 with comparatively large endosperm. The smallest and simplest of flower- 

 ing plants. 



601. Wolflfia Columbiana Karsten. Columbian Frog-spit. Stagnant 

 pools and shallow, permanent waters, E. K. ; not common. Sept. Under 

 the surface. 



602. Wolffia punctata Grisebach. Dotted Frog-spit. Stagnant waters, 

 E. K ; not common. Sept. (S) Floating on the surface. 



603. Wolflfia papulifera Thompson. Pimply Frog-spit. Still waters, 

 Miami county (Mackenzie & Bush). 



604. Lemna gibba L. Gibbous Duckweed. Ponds and slow streams, 

 E K,; frequent. Aug. (S) 



60.5. Lemna minor L. Little Duckweed. Ponds and still waters, E. K. ; 

 occasional. Oct. 



606. Lemna perpusilla Torr. Ovoid Duckweed. Ponds and lakes, E. 

 and S. K. ; common. Three-nerved. Sept. (S) 



607. Lemna minima Philippi. Least Duckweed. Ponds, E. K.; not 

 often seen, but sometimes in great abundance. Oct. (S) 



