378 TREES OF NORTH AMERICA 



the end of August, \' long, persistent on the branches after opening until the spring of the 

 following year; conspicuous from the contrast of the bright red faded petals and the white 

 silky pubescence of the calyx and carpels; seed yV long, and one third as long as its wing. 



A tree, 18-20 high, with a slender often hollow trunk 5 '-6' in diameter, rigid upright 

 contorted branches, and slender branchlets at first bright reddish brown and more or less 

 thickly covered with hoary tomentum, becoming light brown or gray in their second year 

 and marked by large elevated leaf-scars; or more often a low shrub. Winter-buds: axillary 

 minute, acuminate, reddish brown, pubescent. Bark about re' thick, dark red-brown, 

 and broken on the surface into small square persistent plate-like scales. Wood very heavy, 

 hard, close-grained, dark rich brow r n streaked with red, with 14 or 15 layers of annual 

 growth. 



Distribution. Bottoms and rocky sides of gulches, or on grassy slopes; mountain ranges 

 of extreme south western New Mexico (Guadalupe Canon, teste E. A. Means}, southern 

 Arizona, Sonora, and Lower California; arborescent and of its largest size in Arizona on 

 the Santa Catalina Mountains at altitudes of about 5000 above the sea. 



2. LYONOTHAMNUS A. Gray. 



A tree or shrub, with scaly bark exfoliating in long strips, stout terrete pubescent ulti- 

 mately glabrous branchlets, and scaly, acuminate buds. Leaves opposite, long-petiolate, 

 lanceolate, acuminate, rounded or cuneate at base, entire, finely crenulate-serrate or serru- 

 late lobulate below the middle, or sometimes irregularly pinnately parted into 3-8 linear- 

 lanceolate remote lobulate segments, coriaceous, transversely many-veined, dark green 

 above, paler and more or less pubescent below, persistent; stipules lanceolate, acute, minute, 

 caducous. Flowers on slender pedicels, in broad compound terminal pubescent cymose 

 corymbs, with minute acute persistent bracts and bractlets; calyx-tube hemispheric, with 

 1-3 bractlets, tomentose on the outer surface, the lobes nearly triangular, slightly keeled, 

 apiculate, persistent; disk 10-lobed, with a slightly thickened margin; petals 5, orbicular, 

 sessile, white; stamens 15, inserted in pairs opposite the petals and singly opposite the 

 sepals; filaments subulate, incurved, as long as the petals; anthers oblong, 2-celled, the 

 cells opening longitudinally; carpels 2, inserted in the bottom of the calyx-tube, forming a 

 superior glandular, hairy ovary; styles 2, spreading; stigmas capitate, truncate; ovules 4 

 in each cell, suspended; micropyle superior; raphe ventral. Fruit of 2 woody ovoid glan- 

 dular-setulose carpels, dehiscent on the ventral and partly dehiscent on the dorsal suture. 

 Seeds ovate-oblong, pointed at the ends; seed-coat light brown, thin and membranaceous; 

 hilum orbicular, apical; raphe broad and wing-like; cotyledons oblong, acuminate, twice 

 as long as the straight radicle directed toward the hilum. 



Lyonothamnus is represented by a single species found only on the islands off the coast 

 of southern California. 



Lyonothamnus, in honor of its discoverer, William S. Lyon. 



1. Lyonothamnus floribundus A. Gray. Ironwood. 



Leaves 4'-8' long, |' wide when entire, or 4' wide when pinnately divided, when they 

 unfold covered below with hoary deciduous tomentum, at maturity dark green and lus- 

 trous above and yellow-green, glabrous or pubescent below, with an orange-colored 

 midrib. Flowers in June and July, \'-\ r in diameter, in clusters varying from 4 / -8 / across. 

 Fruit ripens in August and September, iV long. 



A bushy tree, rarely 30-40 high, with a single straight trunk 8'-10' in diameter, 

 and slender branchlets at first pale orange color and coated with deciduous pubescence, 

 becoming at the end of their first season bright red and lustrous; usually shrubby, with 

 several tall stems, or in exposed situations a low bush. Bark \' thick, dark red-brown, and 

 composed of numerous thin papery layers, forming after exfoliating long loose strips per- 

 sistent on the stem. Wood heavy, hard, close-grained, bright clear red faintly tinged 

 with orange. 



