PTEROLOBIUM 



PTEROSTYRAX 



2S55 



intro. into England and is occasionally cult., the treat- 

 ment being the same as that given Csesalpinia. The 

 species varies in the size of the Ivs. and in the width 

 and size of the wing of the pod. 



PTERONIA (Greek, wing, referring to the chaffy 

 receptacle). Composite. Small dry or glutinous shrubs: 

 Ivs. opposite or rarely alternate, mostly entire, gla- 

 brous or hairy, often ciliate: heads terminal, solitary 

 or corymbose; involucral scales scarious, often shining; 

 fls. yellow, rarely purple. About 60 species, natives of 

 S. Afr. P. incana, DC., a scrubby divaricate branched 

 bush with the twigs and Ivs. thinly tomentose-canes- 

 cent: Ivs. opposite, sessile, linear-oblong, obtuse: 

 heads sessile, 6-9-fld., golden yellow, involucral scales 

 oblong, subobtuse, at first greenish yellow then fulvous 

 and finally the centers brown: achenes top-shaped, 

 densely and rigidly hairy. B.M. 8380. Occasionally 

 cult, abroad. 



PTEROSPERMTTM (Greek, wing seed; referring to 

 the fact that the seeds are winged). Sterculiacex. 

 Scaly or stellate-tomentose trees or shrubs, suitable for 

 the warmhouse and outdoors in the southern part of 

 the country. 



Leaves 2-ranked, leathery, simple or lobed: infl. 1-3 

 axillary and terminal peduncles, 1- or few-fld.; fls. 

 often elongated; calyx tubular, 5 more or less connate 

 sepals; petals 5, deciduous with the calyx; staminal 

 column short, bearing opposite the sepals 3 linear 

 2-celled anthers between each part of 5 anti-petalous 

 ligulate staminoides: ovary inserted within the top of 

 the staminal column: caps, woody or coriaceous, terete 

 or 5-angled. About 25 species, confined to Trop. Asia. 

 Pterospermums are said to need considerable warmth, 

 and perfect drainage is most essential. They grow best 

 in a mixture of sandy, fibry loam and lumpy peat. 

 Prop, by cuttings of half-ripened side shoots, cut close 

 to the st. 



acerifdlium, Willd. Large tree: Ivs. 10-14x6-12 in., 

 roundish or oblong, often lobed, palmately 5-7-nerved; 

 nerves prominent beneath: bractlets laciniate: fl.-buds 

 oblong, obtuse, 5-angled, rusty tomentose: fls. 5-6 in. 

 across, pure white, fragrant; sepals linear-oblong, thick; 

 petals linear-oblong: caps. 4-6 in. long, 5-celled; seeds 

 many; wing large, thin. B.M. 620. G.W. 7, p. 121. 

 Cult", in S. Calif . F. TRACY HuBBABD.f 



PTEROSTYLIS (Greek, wing column; the column is 

 broadly winged). Orchidacex. Terrestrial herbs with 

 small underground tubers: radical Ivs. ovate; st.-lvs. 

 developed and linear or lanceolate, or reduced to scari- 

 ous sheathing scales: fls. usually green, often tinged red 

 or brown, large and solitary or smaller and several in a 

 raceme: dorsal sepal broad, erect, incurved and very 

 concave; petals lanceolate-falcate, attached to the 

 basal projection of the column; labellum on a short 

 claw at the end of the basal projection of the column, 

 movable; column with a pair of hatchet-shaped or 

 quadrangular wings. About 50 species, mostly Aus- 

 tralian but a few in New Zeal, and New Caledonia and 

 1 in New Guinea. P. curia, R. Br. Lvs. in a radical 

 rosette, usually on long petioles, ovate or broadly 

 elliptical, 5-9-nerved: scapes 1-fld.; usually about 6 in. 

 high; galea erect, acute; lip linear, obtuse, entire, rather 

 longer than the column; wings of the column with the 

 lower lobe long and obtuse, the upper lobe short and 

 broad. Austral. B.M. 3086. O. 1910:104. Cult, to 

 some extent in greenhouses abroad as are the following: 

 P. acuminata, R. Br. Austral. B.M. 3401; P. Bdnksii, 

 R. Br. New Zeal. B.M. 3172; P. Baptistii, Fitzg. 

 Austral. B.M. 6351; and P. n&tans, R. Br. Austral. 

 B.M. 3085. They are prop, by division and thrive in 

 If .-mold lightened by a little sand; the lower third of 

 the pots should be filled with broken crocks. 



F. TRACY HUBBARD. 



181 



PTEROSTtRAX (Greek, pteron, wing; alluding to 

 the winged or ribbed fruit, by which it is distinguished 

 from the allied genus Styrax). Styracacese. Ornamen- 

 tal woody plants grown chiefly for their drooping pani- 

 cles of white flowers. 



Deciduous trees or shrubs, stellate-pubescent: Ivs. 

 alternate, denticulate: fls. in large panicles, terminal on 

 short branchlets; calyx 5-toothed; corolla 5-parted 

 almost to the base; stamens 10, somewhat longer than 

 the corolla and slightly exceeded by the slender style; 

 ovary 3-celled: fr. a ribbed or winged 1-2-seeded nut. 

 Three species in China and Japan. Sometimes united 

 with Halesia, from which it is distinguished chiefly by 

 the panicled drooping infl. and the 5-merous fls. 



These are handsome trees or shrubs with rather large 

 light green leaves and white flowers in showy pendulous 

 panicles, followed by small rather inconspicuous fruits. 

 They are only precariously hardy in sheltered positions 

 as far north as Massachusetts. In June they are very 

 attractive, with their graceful drooping panicles of 

 numerous deutzia-like fragrant flowers. They thrive 

 best in a moderately moist sandy loam and are propa- 

 gated by seeds or layers and also by greenwood cuttings 

 under glass. 



3255. Pterostyrax hispida. 



hispida, Sieb. & Zucc. (Halesia Uspida, Mast.). Fig. 

 3255. Tree, attaining 50 ft., with slender spreading 

 branches forming an open head: Ivs. short-petioled, 

 ovate to oblong, narrowed at the base, acute or acumi- 

 nate, denticulate, almost glabrous or pubescent on the 

 veins beneath, light green above, grayish green beneath, 

 3-7 in. long: panicles 5-10 in. long; fls. creamy white, 

 fragrant, about %m. long: fr. 10-ribbed, thickly cov- 

 ered with bristly hairs, H m - long. June. China, Japan. 

 G.C. II. 22:177'; III. 46:88; 48:125. Gn.8, p. 243; 26, 

 p. 23; 34, p. 111. R.H. 1875, p. 308. G.F. 5:389. 

 M.D.G. 1899:353. G.W. 3, p. 37. F.E. 14:36 (pi. 21); 

 17:457. B.M. 8329. S.I.F. 2:65. G.M. 57:538. 



corymbdsa, Sieb. & Zucc. (Halesia corymbosa, 

 Nichols.). Small tree or shrub: Ivs. short-petioled ; 

 oval or ovate, abruptly acuminate, serrulate with 

 usually bristly teeth, sparingly stellate-pubescent on 

 both sides, 2J^-4H in. long: panicle corymbose, 3^5 

 in. long: fr. with 4-5 narrow wings, tomentulose, J^in. 

 long. June. China, Japan. S.Z. 1:47. S.I.F. 2:65. 

 Seems to be more tender than the preceding species and 

 is but rarely cult. ALFRED REHDER. 



