CYPERACEAE. 



25 



1. D. spicata (L.) Greene. Stems 1-6 dm. long: leaf-blades 2-4 mm. wide: 

 panicle 2-(j em. long: spikelets 8-18 mm. long, 6-16-flowered, pale-green, the 

 flowering scales 3-5 mm. long, acute or acuminate. — Everglades and coastal 

 sand-dunes. — F, K. {Bah., Cuba, Ant.) — Spike-grass. 



Family 2. CYPERACEAE. Sedge Family. 



Grass-like or rush-like caulescent or scapose herbs, often with root- 

 stocks. Stems or scapes solid, or i-arely hollow, often 3-sided or 3-angled. 

 Leaves with closed sheaths : blades naiTow. Flowers perfect or imperfect, 

 in spikelets, one (rarely 2), in the axil of each scale (glume, bract), the 

 spikelets clustered or solitary, 1-many-fIowered. Scales 2-i'anked or 

 spirally imbricate. .Perianth of bristles, or scale-like parts, or wanting. 

 Androecium of 1-3 stamens, or rarely more. Gynoecium of 2 or 3 united 

 carpels. Fruit an achene. 



Flowers of the spikelets, at least one of them perfect. 



Spikelets perfect, or mainly so, rarely of 2 scales and 1 flower. 

 Scales of the spikelets 2-ranked : spikelets several or 



many together in each spike. 1. Cyperus. 



Scales of the spikelets spirally imbricate all around or 

 2-rauked in Abildgaardia in which each scape is 

 terminated by one spikelet. 

 Base of the style not at all, or only slightly, thick- 

 ened, deciduous. 

 Perianth of dilated scales and bristles : spikelet- 



scales pubescent. 

 Perianth of bristles only, or wanting : spikelet- 

 scales glabrous. 

 Base of the style manifestly swollen, persistent as a 

 tubercle on the achene, or deciduous. 

 Perianth present. 

 Perianth wanting. 



Achene not surmounted by a tubercle. 



Spikelets terete, the scales spirally im- 

 bricate. 

 Spikelets flattened, the scales 2-ranked. 

 Achene surmounted by a tubercle. 



Spikelets in umbels or cymes, without an 



imbricate involucre. 

 Spikelets in a head subtended by an imbri- 

 cate involucre. 

 Spikelets polygamous, or rarely of 4 scales and only 1- 

 flowered. 

 Scales of the spikelet 2-ranked. 

 Scales of the spikelets spirally imbricate. 

 Stigmas 3 : style deciduous. 

 Inflorescence paniculate. 

 Inflorescence capitate. 

 Stigmas 2 ; style persistent. 

 Flowers monoecious or dioecious. 



1. CYPERUS [Tourn.] L. Scapose herbs. Leaves basal: blades narrow. 

 Scapes, in our species, simple, triangular, and with one or more bracts at the 

 summit forming an involucre to the umbellate or capitate inflorescence. Eays 

 of the umbel sheathed at the base, usually very unequal, one or more of the 

 heads or spikes commonly sessile. Spikelets flat or nearly terete. Perianth 

 none. Achene not tubercled. — Galingale. 



Style-branches or stigmas 2 : achene lenticular. 



Scales of tlie spikelets obtuse. 1. 



Scales of the spikelets acute or acuminate. 2. 



Style-branches or stigmas .3 : achene trigonous. 



Rachis of the flattened spikelets persistent, the scales 

 falling away. 

 Wings of the rachis none or very narrow. 



Stamens 3 : plants annual. 3. 0. comprcssus. 



C. dctifitif!. 



C. paniculatus. 



