RUTACE^E. (RUE FAMILY.) 109 



southward. June -Sept. Plant 2 -4 high: the flowers loosely panicled 

 at the ends of the branches, hanging gracefully on their slender nodding stalks, 

 the open mouth of the cornucopias-shaped sepal upward. A variety is not rare 

 with spotless flowers, which differs from the I. Noli-tangere of Europe in the 

 more inflexed spur and smaller petals. Spur rarely wanting. 





 5. OX AL IS, L. WOOD-SORREL. 



Sepals 5, persistent. Petals 5, their bases sometimes united, withering after 

 expansion. Stamens 10, usually monadelphous at the base, alternately shorter. 

 Styles 5, distinct. Pod oblong, membranaceous, 5-celled, more or less 5-lobed, 

 each cell opening on the back ; the valves persistent, being fixed to the central 

 column or axis by the partitions. Seeds 2 or more in each cell, pendulous 

 from the axis, anatropous, their outer coat loose and separating. Embryo 

 large and straight in fleshy albumen : cotyledons flat. Herbs, with sour 

 watery juice, alternate or radical leaves, mostly of 3 obcordate leaflets, which 

 close and droop at nightfall. Several species produce (like Impatiens) small 

 peculiar flowers, which are precociously fertilized in the bud and are particularly 

 fruitful ; and the ordinary flowers are often dimorphous or even trimorphous in 

 the relative length of the stamens and styles. (Name from 6vs, sour.) 



* Stemless perennials : leaves and scapes a rootstock or bulb : leaflets broadly obcor- 



date: flowers nearly 1' broad; cells of the pod few-seeded. 



1. O. Acetos611a, L. (COMMON WOOD-SORREL.) Rootstock creeping 

 and scaly- toothed; scope \-flowered (2' -5' high); petals white with reddish 

 veins, often notched. Deep cold woods, Massachusetts to Penn., L. Superior 

 and northward : also southward in the Alleghanies. June. (Eu.) 



2. O. Violacea, L. (VIOLET W.) Nearly smooth; bulb scaly; scapes 

 umbellately several-flowered (5' -9' high), longer than the leaves; petals violet. 

 Rocky places ; most common southward. May, June. 



* * Stems leafy, branching : peduncles axillary : flowers small : cells several-seeded. 



3. O. Stricta, L. (YELLOW W.) Annual or perennial by running sub- 

 terranean shoots ; stems at first erect ; stipules absent ; peduncles 2 - 6-flowered, 

 longer than the leaves ; petals yellow ; pods elongated, erect in fruit. Copses 

 and cultivated grounds : common. May - Sept. Varies greatly in appearance 

 and in the size of its flowers. 



4. O. CORNICULATA, L., if in this district, and truly distinct from 0. stricta, 

 should be known by the stipules at the base of the petioles. (Eu.) 



ORDER 25. RUT ACE m. (RuE FAMILY.) 



Plants with simple or compound leaves, dotted with pellucid glands, abound- 

 ing with a pungent or bitter-aromatic acrid volatile oil, producing hypogynous 

 almost always regular 3 - 5-merous flowers, the stamens as many or twice as 

 many as the sepals (rarely more numerous) ; the 2-5 pistils separate or com- 

 bined into a compound ovary of as many cells, raised on a' prolongation of 

 the receptacle (gynophore) or glandular disk. Embryo large, curved or 



