110 ALISMACEA 



1. ATiISBIA, Linnaens. 

 I. A. Plftntag^o. L. Scape with branches in whorls: leaves ovate to lanceolate or 



narrower: petals Bmall, white or pinkish. In water or mnd. 



2. DAMAS0NIX7M, Jussieu. 



1, S. CalifomicTim, Torr. Scapes 6-18 in. high: leaves ovate to narrowly lanceolate, 

 long-petioled: flowers in 3 or 4 whorls; pedicels 1-2 in. long: petals 3-4 lines long, 

 incised above, white. In water or mud. S. N. Mts. 



3. SAGITTAHIA, Linnsens. 



L S. variabilis, Engelm. Leaves ovate-sagittate or some linear: flowen mostly in 

 3'a: petals white, ronnded J-{ in. long: tubers edible. In water or mnd. 



ORCHID ACE J:. 



Herbs with a more or leas irregnlar perianth of 3 sepals and 3 petals; the lower petal 

 (made so by a twist in the inferior ovary), called the lip, usually unlike the other two 

 which generally resemble the sepals. Stamens and style united fo form the column which 

 is capped by a single perfect 2-celled anther, or (in Cypripedium) with a perfect anther 

 on each side of the stigma over which curves a triangular sterile stamen. Our genera are 

 usually grouped in four tribes here briefly defined. 



I. Anther resting lid-like upon the column, deciduous: poUen-maSses 4 1, 3, 3 



II. Anther united with column, persistent on its face above stigma: pollen-masses 2. . 4 



IIL Anther erect on top of column, persistent: pollen-maases 2-4 5 to 9 



rV. Anthers 2, lateral; the sterile stamen petaloid, incurved 10 



* JItrbi with one to many green leaves: not ptwasitic. 



Leaf solitary from a globose conn. Scape 1-flowered 1 



Scape 6-26-flowered 3 



Leaves several to many from a creeping rootstock 6 



Leaves a pair below the raceme of small flowers, ovate or cordate 7 



Leaves 2 or 3 to many clasping slender or stoutish stems, at least at base. 

 Flowers not leafy-bracted, white or greenish, in spikes or racemes. 



Lip of perianth spurred at base ....-» 4 



Lip not spurred: spike twisted: flowers 3-rankcd 6 



Flowers leafy-bracted, pedicellate, 1-20. 



Lip concave at base, constricted in middle .^ 8 



Lip an inflated sac, the mouth with incurved margin 10 



" * Plants with no green leaves: stems simple, scape-like. 



