“CB eee 

Haloragidaceae 269 
CIRCAEA ENCHANTER’S NIGHTSHADE 
Perennial, low. Leaves thin, opposite, petioled. Flowers small, white, in terminal 
and lateral racemes. Calyx-tube slightly projecting beyond the ovary, deciduous; calyx- 
lobes 2, reflexed. Petals 2, obcordate. Stamens 2, alternate with the petals. Stigma 
somewhat capitate. Fruit a capsule, small, obovoid, densely hispid with hooked hairs, 
indehiscent; cells |—2 (ours 1), I-seeded. (Honor of Circe, a Greek enchantress, who 
is said to have used these plants. ) 
A. Leaves dentate; racemes with minute setaceous bracts subtending the pedicels. W. 
Or: C. alpina L. 
AA. Leaves undulate-denticulate; racemes bractless. WGek: 
C. pacifica Asch. 
HALORAGIDACEAE  Water-milfoil F amily 
Herbs, annual or perennial, glabrous, aquatic (ours) or in mud. Leaves whorled 
(some so in all of ours) or alternate, the submerged ones often pectinate-pinnatifid. 
Flowers perfect or monoicous or dioicous, axillary or in terminal spikes, solitary or clustered 
in the axils. Calyx entire or 2—4-lobed. Petals none or 2—4, small. Stamens 1—8. 
Ovary inferior, ovoid-oblong or short-cylindric, 2—8-ribbed or -winged, |—4-celled; 
styles 1—4. Fruit a nutlet or drupe, flattish, angular, ribbed or winged, indehiscent; 
carpels |-seeded. 
A. Submerged leaves pinnatifid into capillary segments, 3—5 in a whorl or rarely 
some scattered; stem not Equisetum-like; stamens 48; ovary 2—4-celled. 
MyrioPHYLLuM (p. 269) 
AA. All leaves linear or wider, simple, entire, 4—12 in a whorl; stem conspicuously 
jointed and somewhat Equisetum-like; stamen |; ovary |-celled. Hippuris (p. 270) 
MYRIOPHYLLUM WATER MILFOIL 
Submerged leaves pinnatifid into capillary segments. Flowers axillary, 2-bracted, 
usualy monoicous, often interruptedly spicate. Upper. flowers usually staminate: calyx- 
tube none or very short; calyx-limb 2—4-lobed: petals 2—4: stamens 48. Interme- 
diate flowers often perfect. Lower flowers pistillate: calyx none or somewhat 4-grooved, 
minutely 4-lobed; ovary 2—4-celled; ovule | in each cell; styles 4, often plumose. 
Fruit splitting into 4 carpels; carpels bony, indehiscent, I-seeded, smooth or angled or 
tubercled on the back. (Gk. myrios—numberless, phyllon—leaf; the leaves are split 
into very many segments. ) 
A.’ Floral leaves shorter or very little longer than the flowers. 
B. Floral leaves entire or merely dentate; rachis and segments of the foliage leaves 
capillary and of about the same diameter. W. E. 
M. spicatum L. 
BB. Floral leaves pectinate; rachis of the foliage leaves flattish and somewhat wider 
than the segments. W.E. (M. verticillatum for our region.) 
M. verticillatum pectinatum Wallr. 
AA. Floral leaves many times as long as the flowers. 
C. Foliage leaves in whorls of 4—6; carpels smoothish. W. E. 
M. hippuroides Nutt. 
CC. Foliage leaves variously arranged, on the same stem in whorls of 3—5 or 
scattered; carpels with 2 tuberculate ridges on the back. W. 
M. pinnatum B. S. P. 
