Biological Papers. 111. 



CLASS X.* PETALIFERJE. PETAL-BEARERS. 



Monocotyls with Showy-colored Perianth. 

 Floral envelopes herbaceous, foliaceous, more or less colored, in two or 

 more whorls surrounding the carpel, deciduous or partly persistent. Pol- 

 lination principally entomophilous. Fruit mostly capsular; though it may 

 be nuciform, follicular, utricular, or even bacciform. 



Subclass C. ALISMJEFLOR^. Water Plants. 

 Alisma-flowered Monocotyls. 

 Perianth, when present, usually in two whorls, actinomorphous, heter- 

 ochlamydeous, consisting of three persistent herbaceous green sepals and 

 three deciduous chromoplastic highly colored petals. Androecium normally 

 of six stamens, though they may be greater in number or fewer ; filaments 

 short ; anthers with inconspicuous connectives. Gynoecium of three to 

 many distinct carpels, sometimes coherent during anthesis; ovularies su- 

 perior. Aquatic or marsh-inhabiting herbs, with various leaves, eitherwith 

 long petioles and broad laminae or laminodia with their distal ends expanded 

 into blade-like prolaminse; often reduced to phyllodia. 



Order XXII. HYDRALES The Waterworts. 



Inflorescence spathaceous. Flowers arising from a spathe or involucre 

 of one to three bracts. Perianth regular, with three herbaceous or petaloid 

 sepals and three thin petals, or none. Stamens three, or a multiple of 

 three, in one or more whorls, with distinct or partially united filaments. 

 Pollination hydrophilous. Carpels 3 to 15, united, with as many parietal 

 placentae. 



Family 45. Vallisneriace^e. Tape-grass Family. 



Submerged or floating water plants with perennial stolons. Leaves 

 various, with linear grass-like submerged or floating laminodia and small 

 one-nerved pellucid opposite or verticillate and minutely denticulate cauline 

 leaves. Flowers monoecious, dioecious, and polygamous, rarely perfect, 

 arising from an ovoid, obovoid, or tubular twocleft spathe, with sepals 

 and petals three each. Staminate flowers solitary, in threes, or numerous 

 and crowded upon a sessile spadix, detaching at maturity and expanding on 

 the surface of the water, to allow the dry pollen to float away to the stig- 

 mas; stamens on short filaments, in whorls of three or fewer, united at base 

 into a column; anthers bisporangiate. Carpellate flowers solitary in the 

 axils, but with a calyx-tube or a coiled scape just long enough to allow the 

 flower to reach the surface and float on it for pollination; styles three to 

 nine, short; stigmas, three, entire or two-cleft. Perfect flowers like the 

 carpellate ones, but with three to nine stamens. Ovulary unilocular, with 

 three parietal placentae, or with loculi six to nine; ovules numerous, borne 

 all over the placental walls, anatropous or orthotropous. Fruit an inde- 

 hiscent utricle, ripening under water; seeds with straight embryo; without 

 endosperm. 



643. Philotria canadensis Britton. {Elodea Mx ) Ditch-moss. Fresh- 

 water ponds and streams, Miami county. May. (U) 



644. Philotria minor Small. Little Ditch-moss. Ponds and slow streams, 

 S. E. K. ; occasional. May. (AS) 



645. Vallisneria spiralis L. Tape-grass. Quiet waters, Miami, McPher- 

 son. Rice, Reno and Pratt counties; not common. Aug. (ASU) 



