174 CERATOPHYLLACEAE 



Family 45. CERATOPHYLLACEAE. 

 Hornwort Family. 



Submerged aquatic plants with slender branching stems and verticillate dissected 

 leaves. Flowers monoecious, solitary and sessile in the axils, subtended by 8-12-cleft 

 calyx-like involucres. Perianth wanting. Stamens many, hypogynous, with short fila- 

 ments ; anthers appendaged with 2-3 sharp points. Pistil with a single carpel ; style 

 filiform; ovary 1-celled; ovule 1, pendulous. Fruit a nutlet, with a persistent style. 

 Endosperm none ; embryo straight, with the plumule well developed and bearing one 

 or two whorls of filiform leaves. 



Small family containing the single genus and three species. 



1. CERATOPHYLLUM L. Sp. PI. 992. 1753. 

 Characters of the family. [Name Greek, meaning- horn and leaf.] 



Two or three species, of wide geographic range. Type species, Ceratophyllum demersum L. 



1. Ceratophyllum demersum L. Hornwort. Fig. 1760. 



Ceratophyllum demersum L. Sp. PI. 992. 1753. 



Stems varying in length with the depth of the water up to 3 m. Leaves 5-12 in a verticil, 



dichotomously forked into filiform or linear often toothed segments ; nutlets various, either 



smooth or tuberculate, the smooth either with or without a basal spur on each side, and the 



tuberculate either with a narrow spiny-toothed wing or with a broad entire wing. 



Ponds and slow streams, Boreal and Austral Zones; common in the Pacific States and world-wide in its 

 distribution. June— Aug. Several segregates have been proposed based upon the variations in the fruit. 



Family 46. RANUNCULACEAE. 

 Crowfoot Family. 



Annual or perennial herbs or rarely shrubs or woody climbers, with acrid color- 

 less juice. Leaves alternate, or rarely opposite, simple or compound, exstipulate, but 

 the base of the petiole often stipule-like. Pubescence when present composed of 

 simple hairs. Flowers regular or irregular, hypogynous (except in Paeonia). Sepals 

 3-15, generally early deciduous, often petaloid, imbricate (valvate in Clematis). 

 Petals present and of the same number as sepals, more numerous, or sometimes 

 none. Stamens numerous, spirally arranged ; anthers continuous with the filament. 

 Carpels distinct, few to many, rarely solitary, 1-celled. Ovules one to many, anatro- 

 pous. Fruit achenes, follicles or berries. Seeds with a hard endosperm, contain- 

 ing oil. 



About 35 genera and 1100 species, widely distributed, but most abundant in the north temperate regions. 



Carpels few- to several-seeded, becoming follicles or berries (Actaea) in fruit. 



Sepals persistent; flowers large, solitary; petals broad. 1. Paeonia. 



Sepals deciduous. 



Flowers regular. 



Leaves simple. 



Petals none; sepals broad, petaloid; leaves reniform or cordate, not lobed. 2. Caltha. 



Petals narrow; leaves palmately lobed. 3. Trollius. 



Leaves compound. 



Petals when present not spurred. 



Flowers not racemose. 



Petals none; sepals petaloid; leaves not evergreen. 4. Isopyrum. 



Petals present, linear; leaves coriaceous, persistent. 5. Coptis. 



Flowers racemose. 



Racemes simple; fruit a berry. 6. Actaea. 



Racemes usually compound; fruit a follicle. 7. Cimicifuga. 



Petals spurred, showy. 8. Aquilegia. 



Flowers irregular. 



Upper sepal spurred; petals 4; the upper pair spurred and included in the spurred sepal. 



9. Delphinium. 



Upper sepal hooded; petals 2, clawed, inclosed in the hooded sepal. 10. Aconitum. 



Carpels 1 -seeded, becoming achenes. 



Stem leaves whorled or opposite; sepals petaloid; petals none. 



Stem leaves in a single involucral-like whorl; herbs; sepals imbricate. 



Styles short, glabrous or pubescent. 11. Anemone. 



Styles elongated and plumose. 12. Pulsatilla. 



