A. TATARICA. 261 



injection results in a definite reddened wheal, the conclusion is that the patient is super- 

 sensitive to that particular pollen and treatment for desensitization is then begun by 

 making injections at intervals with extracts of gradually increasing strength. When 

 no further reaction is obtained, the patient is assumed to be immune from attacks of 

 hay-fever from the species used. Although some people are sensitive to only one species 

 of pollen, others react to two or more, in which case it is necessary to treat with all of 

 these if perfect immunity is sought. 



6. ATRIPLEX TATARICA Linnaeus, Sp. PI. 105.3, 1753. Plate 38. 



Erect or spreading annual herb, 2 to 15 dm. or more high, widely branched from the 

 base to form tangled masses or spreading plants ; branches rather stout, obtusely angled, 

 nearly glabrous, stramineous, the bark smooth and persistent; leaves alternate, except 

 probably the lower, long-petioled or the upper nearly sessile, ovate or somewhat triangu- 

 lar, either subhastate or cuneate at base, acute or obtuse at apex, 3 to 6 cm. long, 2 to 4 

 cm. wide, deeply or shallowly sinuate-dentate or only undulate, the teeth acute or obtuse, 

 thinly furfuraceous, usually greenish at least on the upper surface, soft and thin; flowers 

 monoecious, the staminate glomerules in slender terminal spikes and panicles 3 to 15 

 cm. long, the pistillate fascicled in the upper leaf -axils; perianth 5-cleft, wanting in the 

 pistillate flowers; fruiting bracts sessile, moderately compressed, united from the nar- 

 rowed base to the middle, from broadly ovate to rhombic or nearly flabelliform, with 

 wide foliaceous margins, 4 to 8 mm. long, 3 to 7 mm. wide, hard and indurated at 

 maturity except for the broad foliaceous coarsely dentate margins, the sides tuberculate 

 or smooth, strongly 3-nerved and reticulate; seed 1.5 to 2 mm. long, brownish; radicle 

 inferior, ascending. 



Introduced along the Atlantic and Gulf coasts from Connecticut to Alabama; widely 

 distributed in the Old World. Type locality, Siberia. Collections: Connecticut, 1908, 

 Bissell (Gr); on ballast, northern terminus of Eighth Avenue, New York City, 1879 

 and 1880, Brown (Gr, NY, US); on ballast, Greenwich Point, Philadelphia, Penn- 

 sylvania, 1874, Parker (Gr, NY) ; waste ground, Pensacola, Florida, Curtiss 6865 (NY) ; 

 Mobile, Alabama, July 22, 1896, Mohr (Gr, US). 



RELATIONSHIPS. 



The hardened fruiting bracts of this introduced species indicate that it is closely 

 related to A. rosea. Its best distinguishing character is the wider separation of the two 

 kinds of flowers, the staminate being assembled into elongated terminal spikes. The 

 leaves are thinner than in rosea, not at all rigid, and are commonly subhastate and almost 

 pinnatifid, so deep are the lobes, and the bracts are more nearly triangular because of the 

 strong lateral angles. The introduced American plants, as far as seen, are fairly uniform 

 in these characters. In the Old World is found a large series of forms, many of which 

 have been named and described. These are based upon habit, color, shape of leaf, 

 margins of bracts, and similar features. Twenty-one are described in Ascherson and 

 Graebner's Synopsis of the Middle European Flora. 



The misdetermination of certain collections of A. tatarica from the Southern States 

 has led to the erroneous inclusion of A. lampa Gillies, a South American species, in 

 the North American flora. The collections so referred are: Pensacola, Florida, Curtiss 

 6865, and Mobile, Alabama, July 22, 1896, Mohr. These specimens have monoecious 

 flowers, the staminate in elongated spikes, the pistillate with triangular very acute 

 bracts, while A. lampa is a shrub with dioecious flowers, the staminate in short 

 rounded clusters, the pistillate with orbicular, very obtuse bracts. 

 ECOLOGY AND USES. 



As an introduced ballast-plant of rare occurrence, Atriplex tatarica is unimportant, 

 both ecologically and economically. 



