April, 1905.] Key, Ohio Elms in Winter Condition. 315 



3t>. Capsule narrowly linear, pedicelled, 2-valved. Elaters present. 



Anthoceros. 

 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). 45. 



38. Thallus barely costate or ecostate. Dumorticra. 

 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. 



Alarchantia. 

 Gemmae in crescent-shaped receptacles. Fertile receptacles cruci- 

 form. Luniilaria. 



41. Perianth present. 42. 

 Perianth none. 43. 



42. Perianth scarcely exserted, 4-5-labed. Receptacle 2-4-lobed with as 



many alternate rib-like rays. Preissia. 

 Perianth exserted half its length and cleft into 8-10 fringe-like seg- 

 ments. Receptacle 4-lobed. Fimbriaria. 



43. Thallus. large, .very indistinctly porose, scaleless below. Receptacle 



hemispherical, acutely 4-8-lobed. Asterella. 

 Thallus s:nall or very large, porose. 44. 



44. Thallus very large, without scales below. Receptacle conical, 



membraneous. Conoccphahis. 

 Thallus small with purple scales below. Receptacle conic, hemi- 

 spherical, truncately 3-4-lobed. Grimaldia. 



45. Capsule sessile on the thallus; involucre inflated-pyriform. 



Spit aerocephalus. 

 Capsule immersed in the thallus; involucre none. Riccia. 



KEY TO THE OHIO ELMS IN THE WINTER CONDITION. 



LixDLEY M. Smith. 



Ulmus 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. ftilva 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. campcstris L. English Elni 



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. 3. 



3. None of the branches corky-winged ; buds pointed but rather elliptical, 



glabrous or nearh' so. U. amcricana L. White Elm 



3. Some or many of the branches corky-winged ; buds very much pointed, 



somewhat pubescent. U. raccmosa Thomas. Cork Elm 



