ULMACEiE. SILVA OF NORTH AMERICA. 



39 



ULMUS. 



Flowers perfect or rarely polygamous ; calyx 4 to 9-lobed, the lobes imbricated 

 in aestivation ; corolla ; stamens 4 to 9, erect before anthesis ; disk ; ovary superior, 

 1 or rarely 2-celled ; ovule solitary, suspended. Fruit a compressed samara, peripter- 

 ous. Leaves alternate, 2-ranked, deciduous or sub-persistent, furnished with stipules. 



Ulmus, Linngeus, Gen. 68 (1737). — Adanson, Fam. PL Microptelea, Spachj^^zw. ^Sci. iV^af. s^r. 2, xv-358 (1841). 

 ii- 377. — A. L. de Jussieu, Gen. 408. — Endlicher, Endlicher, Gen. Suppl. ii. 29. — Meisner, Gen. ii. 370. 



Gen. 276. — Meisner, Gen. ^51. — Baillon, Hist. PL vi. Chsetoptelea, Liebmann, Vidensk. Medd. fra not. For. 

 184. — Bentham & Hooker, Gen. iii. 351. — Pax, Engler Kjohenh. 1850, 76. 



& Prantl Pfianzenfam. iii. pt. i. 62. 



Trees or rarely shrubs^ with watery juice, deeply furrowed bark, slender 



ed slightly 



zigzag branchlets often furnished with corky wings, and fibrous roots. Leaf -buds ^ formed early in the 

 season in the axils of leaves of the year, covered with numerous ovate rounded chestnut-brown glabrous 

 puberulous or hirsute scales closely imbricated in two ranks, increasing in size from without inward ; 

 scales of the outer rows sterile ; those of the inner rows accrescent, replacing the stipules of the first 

 leaves, deciduous, marking the base of the branchlet in falling with persistent ring-like scars. Leaves 

 conduplicate in vernation, alternate, two-ranked, petiolate, simply or doubly serrate, penniveined, decid- 

 uous or rarely subpersistent ; stipules lateral, hnear-lanceolate to obovate, entire, free or connate at 

 the base, scarious, inclosing the leaf in the bud, caducous. Inflorescence-buds ^ axillary near the ends 

 of the branches, similar to but rather larger than the leaf-buds, the outer scales sterile, the inner 

 bearing flowers and rarely leaves. Flowers, perfect in the American species, minute, articulate on 

 slender bibracteolate pedicels produced from the axils of linear acute scarious bracts in pedunculate 

 or subsessile fascicles or cymes, appearing in early spring before the leaves in the axils of those of the 

 previous year or autumnal in the axils of leaves of the year. Calyx campanulate, four to nine, usually 

 five-lobed, membranaceous, marcescent. Stamens as many as and opposite the lobes of the calyx, 

 hypogynous ; filaments fihform or slightly flattened, erect in the bud, exserted after anthesis ; anthers 

 oblong, emarginate, subcordate at the base, attached on the back below the middle, extrorse, two-celled, 

 the cells opening longitudinally. Ovary sessile or stipitate, compressed, glabrous or hirsute, crowned 

 with a simple deeply two-lobed style, the spreading lobes papillo-stigmatic on the inner face, usually 

 one-celled by abortion, rarely two-celled ; effete or rudimentary in the staminate flower ; ovule solitary, 

 suspended from the apex of the cell, amphitropous ; micropyle extrorse, superior. Fruit ovate or oblong, 

 often oblique, sessile or stipitate, surrounded at the base by the remnants of the calyx, membranaceous ; 

 seminal cavity compressed, slightly thickened on the margin, chartaceous, produced into a thin reticu- 

 late-venulose membranaceous light brown broad or rarely narrow wing naked or ciliate on the margin, 



1 Ulmus does not form a terminal bud, the end of the branch xvii. 184, t. 12, f . 3 ; BulL Torrey Bot Club, xix 



dying and dropping off early in the season, leaving a small nearly 

 orbicular pale scar by the side of the upper axillary bud which 

 nrolonffs the branch the following spring (Foerste, Bot. GazeUe^ 



XX 



Nov, Act Cur. xxii. 307, t. 28. — Hitchcock, Trans. St. 



Woody Plants of Manhattan in their Wt 



ter Condition, 16. 



