REYNOSIA 



RHAMNUS 



2923 



gins revolute: fls. in axillary umbels, borne in May: fr. 

 ripens in Nov. or the following spring. S.S. 2:56. 



F. TRACY HuBBARD.f 



RHABDOTHAMNUS (Greek, rod and bush, a 

 shrub with many rod-like branches). Gesneridceas. 

 Divaricately branched shrub, with slender branches: 

 Ivs. small, opposite, petioled, rotundate, coarsely den- 

 tate, often dissimilar: pedicels solitary in the axils, 

 filiform and without bracts: fls. red-striped; calyx free, 

 deeply 5-cleft, the lobes membranaceous, acuminate; 

 corolla tubular-campanulate; the limb slightly oblique, 

 somewhat 2-lipped, the lobes 5, rotundate, spreading 

 and subequal; stamens 4, perfect: caps, ovate, acumi- 

 nate, coriaceous, finally 4-valved. One species, New 

 Zeal. R. Soldndri, A. Cunn. A much-branched, hispid 

 shrub 1-3 ft. high: branches very slender, spreading at 

 right angles: Ivs. opposite, often in unequal pairs, oval 

 or orbicular, coarsely toothed: fls. axillary, solitary, 

 about 1 in. long; calyx hispid, 5-lobed, lobes lanceolate, 

 acute; corolla glabrous, orange, striped red, limb 

 2-lipped, upper lip smaller, lower lip deeply 3-lobed, the 

 lobes rounded: caps, ovoid acute. New Zeal. B.M. 

 8019. G.C. III. 37:146. 



hardy North, R. crocea and R. ilicifolia are to be recom- 

 mended for their ornamental bright red fruits. Buck- 

 thorns are useful for planting in shrubberies; they like a 

 rather moist soil, especially R. lanceolata, R. alnifolia, 

 R. caroliniana, and R. Frangula, and grow well in 

 shaded or partly shaded situations, but R. cathartica 

 and its allies prefer dry soil. R. cathartica is a valuable 

 hedge plant, though it is now not used so extensively 

 as in the past. The species are propagated by seeds 

 stratified or sown in fall, and by layers. Some, as R. 

 lanceolata, R. fallax, and R. alnifolia, are propagated by 

 cuttings; R. Purshiana, has been successfully raised in 

 England from softwood cuttings put in mild bottom 

 heat under glass about the middle of July. The ever- 

 green species are propagated by cuttings of ripened 

 wood under glass. Rarer kinds are sometimes grafted, 

 those of the Frangula group usually on R. Frangula 

 and the true buckthorns on R. cathartica or allied 

 species. 



Alaternus, 10. 

 alnifolia, 6. 

 alpina, 4, 5. 

 angustifolia, 10, 15. 

 aspleniifolia, 15. 

 calif qrniea, 11. 

 caroliniana, 13. 

 castanese folia, 5. 

 cathartica, 1, 2. 

 colchica, 5. 



INDEX. 



crenata, 2, 14. 

 crocea, 8, 9. 

 dahurica, 2. 

 fallax, 4. 

 Frangula, 15. 

 prandifolia, 5. 

 heterophylla, 15. 

 ilicifolia, 9. 

 imeretina, 5. 

 incana, 11. 



japonica, 3. 

 lanceolata, 7. 

 latifolia, 15 andsuppl. 

 libanotica, 5 and 



suppl. 



nipponica, 2. 

 oleifolia, 11. 

 Purshiana, 11, 12. 

 tomentella, 11. 



KEY TO THE SPECIES. 



A. Winter buds scaly: petals usually 4* 

 sometimes 5 or wanting: seeds (not 



RHAMNELLA (referring to its close affinity to 

 Rhamnus). Rhamnacese. About 6 species in E. Asia. 

 Deciduous shrubs or small trees: Ivs. alternate, stipu- 

 late, serrulate: fls. small, green, in axillary clusters; 

 sepals, petals, and stamens 5; ovary incompletely 

 2-celled: fr. a black drupe with a 1-seeded stone. In 

 habit resembling Rhamnus, but in fls. and frs. more 

 like Berchemia. Only the following species is in cult.; 

 it seems somewhat tender and has^particular oW 



mental qualities; cult, and prop, like rhamnus. R. thin cotyledons recurred at the mar- 



franguloides, Weberbauer (R. japonica, Miq. Micro- ffl - ns; fl s- imperfectly dioecious, 



rhamnus franguloides, Maxim.). Small tree, to 30 ft.: (Eurhamnus.) 



Ivs. ovate-oblong, acuminate, finely serrulate, with 5-10 B. Lvs. opposite: spiny shrubs. 



pairs of veins, glabrous except on the veins beneath, c. Shape of hs. ovate to oblong. 



2-5 in. long: fls. in 5-15-fld. clusters: fr. cylindric- D. Length of Ivs. lYz-3 in.; hs. 



oblong black, H m. long. Japan, Korea E. China. DD */ *g%fltfi 



fe.l.i . 2: 48. ALFRED REHDER. oblong-elliptic to oblong, 



leathery 2. dahurica 



RHAMNUS (its ancient Greek name). Including cc. Shape of hs. obovate, cuneate at 



Frdnqula. Rhamnacese. BUCKTHORN. Ornamental the base .. 3. japonica 



woody plants grown chiefly for their handsome foliage BB - Lvs - alternate: unarmed shrubs. 



and some also for their attractive fruit. c - *fe*SS5l*Ji 



__ .. i! 11 j_ AJ * CC-6/ o UJ i/trtrto * & HO * 



Deciduous or evergreen shrubs or small trees, some- E Branchlets and hs. beneath 



times spiny: Ivs. alternate or opposite, short-petioled, glabrous 4. fallax 



with small deciduous stipules, penninerved, serrulate EE. Branchlets and hs. beneath 



or entire: fls. small, in axillary clusters, umbels or pubescent 5. imeretina 



racemes, perfect, polygamous or dioecious; sepals, pet- DD. Pairs of veins 4-9. 



als and stamens 4-5, petals sometimes wanting; style E - Fls - 5-merous, apetalous: Ivs. 



usually undivided; ovary 2-4-loculed: fr. a globular or : : /, . " 



oblong" 2-4-seeded drupe; nutlets with a leathery ^ ^.^T^L^. 7. lanceolata 



usually dehiscent wall. About 100 species native cc. Foliage evergreen. 



chiefly to the temperate regions of the northern nemi- D Veins 5-9 on each side: IDS. 



sphere. A few species are found in the tropics and as %-j %in. long: fls. apetalous. 



far south as Brazil and S. Afr. Several species yield E. Lvs. glandular denticulate: 



yellow or green dyes and the frs. and bark of some are fls. 4-merous 8. crocea 



used medicinally. The wood of R. Frangula is made into EE. Lw spinulose-dentate: fl*- ....... 



charcoal valued for the manufacture of gunpowder. 0/ * tT"^,>i ' '^ P -' i Uicifolia 



i i -.i 11 DD. Veins oo on each siae. ivs. 



The buckthorns are handsome shrubs with generally y_ 2 in long . ^ s-merous, 



bright green often rather large leaves and with incon- ^^ petals.. .'lO. Alaternus 



spicuous greenish flowers usually in axillary clusters ^ winter buds naked: petals 6: seeds 



followed by berry-like, usually black, rarely red, fruits. convex at the back, not grooved, with 



Many of the species as R. cathartica, R. dahurica, R. flat and fleshy cotyledons: unarmed 



fallax, R. Frangula, and R. alnifolia can be depended shrubs with alternate hs. (Frangula..) 



upon as hardy, while R. Purshiana and R. lanceolata B. Fls. in peduncled umbels. 



are hardy at least as far north as Massachusetts. R. c. Foliage evergreen 11. calif ornica 



imeretina and R. caroliniana are somewhat more tender. cc - Foliage deciduous. 



The handsomest in foliage are R. fallax and R. imere- D - A ^^Jte' " 



Una and the evergreen R. ilicifolia and R. crocea. R. E Pe d un cles usually longer than 



Purshiana, R. caroliniana, R. alnifolia, R. dahurica, t ne petiole: hs. with 6-15 



and R. Frangula are also noteworthy on account of pairs of veins, usually 



pretty foliage. Of the evergreen species which are not obtuse 12. Purshiana 



