182 LYTHRACE.E. (LOOSESTRIFE FAMILY.) 



* * Anthers oblona, straight, without any spur: flowers few, sessile. 

 3. R. cilibsa, Michx. Stem square, glabrous; leaves broadly ovate, 

 ciliate with long bristles; calyx glabrous. — Maryland and southward. 



Order 41. LYTHBACEJI. (Loosestrife Family.) 



Herbs, with mostly opposite entire leaves, no stipules, the calyx enclosing 

 but free from the 1 -i-celled many-st < di d ovary and membranous pod, and 

 bearing the 4-7 deciduous petals and 4-14 stamens on its throat; the latter 

 lower down. Style 1 : stigma capitate, or rarely 2-lobed. — Flowers axillary 

 or whorled, rarely irregular, perfect, sometimes dimorphous or even tri- 

 morphous, those on different plants with filaments and style reciprocally 

 longer and shorter. Petals sometimes wanting. Pod often 1-celled by 

 the early breaking away of the thin partitions : placentae in the axis. 

 Seeds anatropous, without albumen. — Branches usually 4-sided. 



* Flowers regular, or nearly so. 



1. Amman ilia. Calyx short, 4-angled, not striate. Petals 4, or none. Stamens 4, rarely 2. 



2. L) thrum. Calyx tubular-cylindrical, striate. Petals 5-7. Stamens 5 - 14. 



3. IVesrea. Calyx short-campanulate or hemispherical. Stamens 10 - 14, exserted. 



* * Flowers irregular : petals unequal. 



4. Cuphea. Calyx spurred or enlarged on one side at the base. Stamens 12. 



1. AMMANNIA, Houston. Ammannia. 



Calyx globular or bell-shaped, 4-angled, 4-toothed, usually with a little horn- 

 shaped appendage at each sinus. Petals 4 (purplish), small and deciduous, 

 sometimes wanting. Stamens 4, rarely 2, short. Pod globular, 2 - 4-celled. 

 — Low and inconspicuous smooth herbs, with opposite narrow leaves, and small 

 greenish flowers in their axils, produced all summer. (Named after Paul 

 Ammann, a German botanist anterior to Linmvus.) 



§ 1. Calyx with manifest tooth-like or horn-shaped appendages at the sinuses: pod 4- 

 cel/ed : plants of low or wet ground; ours are annuals. 



1. A. humilis, Michx. Leaves tapering at the base or into a short petiole, 

 linear-oblahceolate or somewhat spatulate ; flowers solitary or 3 together in the 

 axils of the leaves, sessile; style very short. — Massachusetts to Michigan, 

 Illinois and southward. 



2. A. latifblia, L. Leaves linear-lanceolate (2' -3' long), icith a broad 

 auricled sessile base; style sometimes very short, sometimes slender. — Ohio, 

 Illinois, and southward. Ship-yards, Philadelphia, an immigrant from the 

 south, C. F. Parker. 



§ 2. HYPOBRl'CHIA, M. A. Curtis. Appendages at the sinuses of the calyx 

 mere callous points or none : petals none: pod 2-celled. 



3. A. Nuttallii, Gray. Submersed aquatic, or sometimes terrestrial, 

 rooting in the mud ; leaves linear, when immersed elongated, thin, and closely 

 sessile by a broad base, when out of water shorter and contracted at the base; 

 flowers mostly solitary in the axils, sessile, small; calyx with broad triangular 

 lobes; style very short. (Peplis diandra, Nutt., but stamens usually 4. Hypo- 



