84 Rhodora [May 
brevissimos vel rosulatos ferens. Caulis viridis vel aetate paulum 
rubro-tinctus, superiore parte fere teres, inferiore parte interdum sub- 
angulosus, pilis brevibus arcuatis crispis aliisque multo longioribus 
patentibus basi rubro- vel viridi-tuberculatis vestitus. Folia utrinque 
pubescentia, acuminata, petiolata, denticulata, inferiora spatulata 
15-24 cm. longa, 3-4 cm. lata, saepe ad basin versus pinnatifida, 
mediocria anguste lanceolata, 12-18 cm. longa, 22-33 mm. lata, supe- 
riora 6-8 cm. longa 10-20 mm. lata. Inflorescentiae plerumque 
simplices, vel primaria spicis paucis lateralibus strictis quam terminali 
multo brevioribus instructa. Bracteae virides foliaceae persistentes 
sessiles ca. 5 cm. longae, 6-7 mm. latae, denticulatae, apicem hypan- 
thii plerumque attingentes, pubescentes. - Flores mediocri ca. 72 mm. 
longi, textura firmiusculi, non cito marcescentes. Ovarium ca. 14 
mm. longum dense cum pilis ascendentibus longis acutis aliisque 
rectis brevibus apice rotundatis viscidis tectum. Hypanthium ca. 
38 mm. longum viscido-pubescens etiam pilis longioribus curvatis 
exornatum. Calycis segmenta nondum explicata gemmam quadran- 
gulam 23-25 mm. longam, 5 mm. crassam, ambabus pilorum speciebus 
dense vestitam formantia, apicibus liberis viridibus inter se appressis 
terminalibus 3-5 mm. longis. Petala cuneato-obcordata profunde 
emarginata firmiuscula plana flava. Fructus 2.5-3.3 cm. longus a 
bractea persistenti superatus basi 5 mm. crassus apicem versus angus- 
tatus, pubescens, valvulorum apicibus truncatis. Semina 1.5 mm. 
longa.— Type, Atkinson No. 1, Ithaca, New York. 
The following summary will serve to indicate the characters which 
distinguish these three species from one another. It will of course 
prove entirely misleading if any attempt is made to apply it in the 
identification of Oenotheras from other localities, without checking 
up other characters included in the foregoing diagnoses. Neverthe- 
less it is presented in the hope that it may be useful to local botanists 
who would take an interest in the problem of differentiating their 
local elementary species of Oenothera if they knew the nature of some 
of the characters which have been found constant in heredity and 
which should therefore be looked for in the field. 
Free tips of the calyx segments infraterminal; therefore widely separated 
m-bud ub eo ee ae ae es ee el Oe. angustissima. 
Free tips of the calyx segments terminal; therefore in contact in bud. 
Bracts caducous when the flower wilts............... Oe. nutans. 
Bracts persistent until the capsules ripen......... Oe. pycnocarpa. 
Oenothera angustissima. Rosette leaves flat, green, not spotted, 
red-nerved, becoming red in the winter, outer ones sinuate-dentate. 
Stem red, terete with no red-tuberculate hairs. Leaves almost 
glabrous, fiery red in autumn. Bracts persistent, red at the base. 
