MATERIALS TOWARD A MONOGRAPH OF THE GENUS CITHAREXYLUM . II Harold N. Moldenke 1. Modem living species. 2. Branches and branchlets armed with spines. Section I. Spin -osae Walp, 3. Spines often absent from the twigs; leaf -blades very firm-ly chartaceous, barbellate in the axils of the secondaries beneath; Brazil, Argentina, Paraguay, and Uruguay C. montevidense. 3a, Spines conspicuous even on twigs; leaf-bTades chartaceous or submembranous, not barbellate beneath; Bolivia and Peru, U. Branches and branchlets very acutely tetragonal, con-spicuously U-nargined, straight, not especially stiff; nodes conspicuously annulate. 5. Leaf -blades mostly serrate, chartaceous, densely im-pressed-punctate beneath; Peru C . herrerae . 5a. Leaf -blades entire, submembranous, not impressed-punctate beneath; Bolivia and Peru C. andinum . Ua. Branches and branchlets mostly obtusely tetragonal or sub terete, not margined, often more or less flexuous, very stiff; nodes usually obscurely annulate. 6. Leaves glabrous or only slightly appressed-pilose a-long the midrib beneath C. psilacanthum . 6a. Leaves rather densely pubescent beneath. 7. Petioles 1 — 3 mm, long; branches usually not flexu-ous; leaf -blades 0.7 — 1.7 cm, long, 3.5 — 10 mm, wide; racemes to 1 cm, long C, weberbaueri . 7a. Petioles 3 — 15 nm, long; branches mostly flexuous; leaf-blades 2.2 — 5.8 cm. long, 7~30 mm. wide; ra-cemes 1.5 — 2.5 cm. long C. f lexuosum . 2a. Branches and branchlets not anned. Section II. Inermia Walp. 8. Leaves very small, 2 — 15 mm. long, 1 — h mm, wide, sessile, clustered on abbreviated spurs; plants with the aspect of Lyciiim barbinode; Mexico and Texas. 9, Leaf -blades densely canescent-pubescent on both siirfaces C. brachyanthum . 9a. Leaf-blades glabrous on both surfaces, . .C. spathulatum . 8a, Leaves mostly larger, usually petiolate; plants not with the aspect of Lycium barbinode. 10. Leaf -blades linear, linear-oblong, or linear-oblanceo-late. 11, Racemes 1 — 3 cm, long, with numerous flowers; leaf-blades firmly chartaceous or subcoriaceous when mat-ure; vein and veinlet reticulation prominulous and conspicuous throughout on both surfaces; Haiti C. stenophyllum . 11a. Racemes very much abbreviated, 1 — 5-7Towered, incon-262
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