MYfllCACEAE (SWEET GALE FAMILY) 329 



* Petioles terete or channeled, but little if at all laterally flattened. 

 •*- Young leaves and petioles white-tomentose ; capsule slender-pediceled. 



4. P. heterophylla L. (Downy F.) Tree 10-25 m. high ; leaves ovate, with 

 a somewhat truncate -or cordate base, obtuse, crenate, at length nearly smooth, 

 except on the elevated veins beneath ; fertile catkins few-flowered ; stamens 

 12-60; capsules 1-1.3 cm. long, equaling the pedicels. — Borders of river 

 swamps, Ct. to Ga. ; also from O. to Ark. and La. 



-H- +- Young leaves and petioles not white-tomentose ; capsule stout-pediceled. 



5. P. balsamifera L. (Balsam P., Tacamahac.) Tree 6-30 m. high, the 

 large buds varnished with a copious fragrant resin ; leaves ovate-lanceolate 

 to cordate-ovate, gradually tapering and pointed, finely crenate, smooth on both 

 sides, silvery and reticulately veined beneath ; scales dilated, slightly hairy ; 

 stamens 20-30 ; capsule ovoid, 2-valved. — Borders of rivers and swamps, Lab. 

 to Alaska, s. to n. and w. N. E., Mich., Minn., etc. 



6. P. caxdicans Ait. (Balm of Gilead.) Leaves broader and more or less 

 heart-shaped, petiole and loioer surface hairy. (P. balsamifera, var. Gray.) 

 — Common in cultivation and freely escaping ; perhaps of Asiatic origin. 

 (Introd.) 



** Petioles laterally flattened. 



7. P. deltoides Marsh. (Cotton-wood, Necklace P.) Tree 15-30 m. high ; 

 leaves broadly deltoid, with numerous crenate serratures and narrow very acute 

 acumination. sometimes ovate, rarely cordate, on elongated petioles ; scales 

 lacerate-f ringed, not hairy ; stamens 60 or more; capsules on slender pedicels, 

 6-10 mm. long, in long catkins, ellipsoid-ovoid, o-4:-valved. (P. monilifera 

 Ait.) — Borders of streams, w. Que. and N. H. to Fla., w. to the Rocky ]Mts. 



P. NIGRA L., the Black P. of Eu., a pyramidal tree somewhat resembling the 

 preceding but with the less lustrous rhombic-deltoid smaller leaves broader 

 than long, more finely crenate, and its var. italic a Du Roi, the Lombardy P., 

 with strictly ascending branches, are spreading from cultivation. (Introd. 

 from Eu.) 



MYRICACEAE (Sweet Gale Family) 



Monoecious or dioecious shrubs, with each kind of flowers in short scaly cat- 

 kins, and resinous-dotted often fragrant leaves, — differing from the Birches 

 chiefly in the 1-celled ovary with a single erect orthotropus ovule, and the drupe- 

 like nut. Involucre and perianth none. , 



1. IVEYRiCA L. 



The only genus. — Flowers solitary under a scale-like bract and with a pair 

 of bractlets, the sterile in ellipsoid or cylindrical, the fertile in ovoid or globular 

 catkins, from axillary scaly buds ; stamens 2-8 ; filaments somewhat united 

 below ; anthers 2-celled. Fruit small, globular or short-cylindric, dry, coated 

 with resinous grains or wax. ^ (Mi^pt/c??, the ancient name of the Tamarisk or 

 some other shrub ; perhaps from /nvpi^eiv, to perfume.) 



* Mostly dioecious; fertile catkins ovoid; ovary loith 2-4 scales at base; nut 



globular ; leaves entire or somewhat serrate. 



1. M. Gale L. (Sweet Gale.) Shrub 1-1.5 m. high; leaves wedge-lav- 

 ccolate, serrate toward the apex, pale, later than the flowers; sterile catkins 

 closely clustered; nuts imbricated in heads, 2-winged by the two thick ovate 

 scales which coalesce with its base. — Borders of ponds, and in swamps, Lab. to 

 N. E., along the Great Lakes to Minn., and northwestw. ; s. in the mts. to Va. 

 April, May. (Eurasia.) 



2. M. cerlfera L. (Wax Myrtle.) Leaves (1-1.6 cm. broad) lanceolate, 

 narrowed at the base, entire or sharply toothed toward the acute apex, shining 

 and resinous-dotted both sides, somewhat preceding the flowers, fragrant ; sterile 



