196 BOTANY. 



Rothrock (733), in 1874. Evidently allied lo three Mexican species which 

 have also umbelliform cymes; the innermost involucral leaves bear single 

 flowers, the outer ones usually two, and a later secondary flower is borne on 

 a shorter peduncle behind a primary one. This is the only Western species 

 yet discovered. — Plate XXI. Natural size. 1. Flower, 5 diameters. 2. 

 Mature capsule, cross-section, about 5 diameters. 3. Vertical section 

 through flower, about 10 diameters. 



Pleurogyne* rotata, Griseb. Gray, Syn. 124. (/Swertia rotata, L.). — 

 Stems 2-10' high, the smallest ones one-flowered, others thyrsoid-branched, 

 many-flowered ; loaves lance-linear ; sepals linear, acute, as long as the 

 milk-white (f-1' wide) corolla, acute at both ends 



Moist, grassy places in Colorado, sometimes in large patches, and 

 then disappearing again for years. The spreading flowers of this and the 

 next two genera afford the best opportunity of observing the action of the 

 versatile anthers as they slowly turn from the introrse to the horizontal, and 

 then to the extrorsely reversed position, as explained above. The glands 

 on the base of the corolla-lobes are distinct enough, but the surrounding 

 scale is apparently not, as it is ignored by many botanists ; I have seen 

 it variable, longer or shorter, but always present ; when fully developed, 

 it forms a complete crested or fringed funnel The stigma of this plant is 

 most peculiar, formed as it is directly on the commissure of both carpels 

 and representing a broad stigmatic line commencing about f " below the non- 

 stigmatose apex, running down the sides to the same distance above the base, 

 so that we have here a two-carpellary ovary with two lateral, but without 

 any apical stigma. This line is beset with elongated stigmatic cells or 

 papillae about 0.1"™ long and I as wide. At the proper time, numerous 

 pollen-grains are found adhering to the stigma, many of them developing 

 their tubes. The seeds I have been able to examine were not fully 

 matured, but such as they are, they appear oval-oblong, not flattened nor 

 margined, but slightly angular and nearly 0.5 mm in the longer diameter 



* Pleurogyne, Eschsch. — Erect annuals of cold or alpine regions, with opposite leaves, few or 

 numerous whitish flowers in a fastigiate'y much-branched panicle; corolla rotate, often 4-parted, in 

 our species with a pair of nectariferous pits at the base of the lobes surrounded by a funnel-shaped crest 

 or a fringed scale; stamens versatile ; ovary lanceolate, bearing the linear stigmas decurrcnt down the 

 sides on the sutures ; ovules abundant on the broad placentae on both sides of the sutures ; capsule oval, 

 pompressed ; seeds oblong, smooth. 



