April, 1905.] Key, Ohio Elms in Winter Condition. 
315 
.3(). Capsule narrowly linear, pedicelled, 2-valved. Elaters present. 
,-l nthoccros. 
Capsule very short, sessile, not valved below middle. No elaters. 
Xotothylas. 
37. Capsule pendent from the underside of a peduncled disk or cruciately 
arranged into 4 horizontal segments (Marchantiaceae). 38. 
Capsule sessile on the thallus or immersed in it (Ricciaceae). 4.5. 
38. Thallus barely costate or ecostate. Dumortiera. 
Thallus plainly costate. 39. 
39. Gemmae present on sterile stems. 40. 
Gemmae none. 41. 
40. Gemmae in cup-shaped receptacles. Fertile receptacle 7-11-rayed. 
Alarcliantia. 
Gemmae in crescent-shaped receptacles. Fertile receptacles cruci- 
form. Lunnlaria. 
41. Perianth present. 42. 
Perianth none. 43. 
42. Perianth scarcely exserted, 4-5-lobed. Receptacle 2-4-lobed with as 
many alternate rib-like rays. Prcissia. 
Perianth exserted half its length and cleft into 8-10 fringe-like seg- 
ments. Receptacle 4-lobed. Ftmbriaria. 
43. Thallus large, very indistinctly porose, scaleless below. Receptacle 
hemispherical, acutely 4-8-lobed. Astcrella. 
Thallus small or very large, porose. 44. 
44. Thallus very large, withovxt scales below. Receptacle conical, 
membraneous. Conocephalns. 
Thallus small with purple scales below. Receptacle conic, hemi- 
spherical, truncately 3-4-lobed. Grimaldia. 
45. Capsule sessile on the thallus; involucre inflated-pyriform. 
S phacrocephaliis. 
Capsule immersed in the thallus; involucre none. Riccia. 
KEY TO THE OHIO ELMS IN THE WINTER CONDITION. 
Lin'dley M. Smith. 
Ulmns L. Trees with medium heavy and medium hard wood 
and rough flaky bark in ridges; twigs brown, the terminal bud 
self-pruned; visible bud scales several, dry; leaf scars semi-oval, 
2-ranked, oblique; bundle scars 3; stipular scars prominent; pith 
small, cylindrical, solid; some with corky ridges on the twigs, 
others with abundant self-pruning scars either in the annual 
nodes or at the base of the twig. 
1. Twigs very rough pubescent; inner bark mucilaginous, pleasant to the 
taste; buds very hairy at the tips; twigs never self-pruned; buds 
shed abundantly. U. fulva Michx. Slippery Elm 
1. Twigs glabrous or slightly pubescent; not mucilaginous or slightly so, 
rather bitter; buds glabrous or if hairy rather small and pointed. 2. 
2. Buds ovate short pointed, bud scales quite hairy; twigs without self- 
pruning joints in the annual nodes; none of the branches corky 
winged; cultivated. U. campestris L. English Elrn 
2. Buds ovate-conic with long points, bud scales glabrous or somewhat 
pubescent; twigs with self-pruning joints in the annual nodes, often 
leaving peculiar stumps; native. ,T 
3. None of the branches corky-winged ; buds pointed but rather elliptical, 
glabrous or nearly so. U. amcricana L. White Elm 
3. Some or many of the branches corky- winged ; buds very much pointed, 
somewhat pubescent. U. racemosa Thomas. Cork Elm 
