The Flora of the Cayuga Lake Basin 151 



a. Stems 3 mm. in diam., flexuous ; umbels 2 or more, rarely solitary ; lower bract 

 scarcely longer than the other (longer when umbel is solitary) ; pedicels slightly 

 longer than the second bract ; plant coarser. 2. S. gramineum 



1. S. angustifolium Mill. (S. anceps of Cayuga Fl., first form.) Blue-eyed Grass. 

 Damp grassy fields, in sandy or gravelly neutral or acid soils ; rather common. 



June. 



Generally distributed in the gravels of the basin; absent on the clays (?). 



Newf. to B. C., southw. to Va., N. C. (?), Mich., Minn., including the Atlantic 

 Coastal Plain, and in the Rocky Mts. 



2. S. gramineum Curtis. (S. anceps of Cayuga FL, second form.) Blue-eyed 



Grass. 



In situations similar to the preceding, perhaps in more acid soils ; equally common. 

 June-July 10. 



Newf. (?) and N. S. to Minn., southw. to Fla., Ark., and Tex.; more common on 

 the Coastal Plain than the last-named species. 



28. ORCHIDACEAE (Orchid Family) 



Artificial Key to the Genera 9 



a. Anthers 2, lateral on the column, with a third enlarged sterile flattened stamen 



partly closing the orifice of the moccasin-shaped labellum. 1. Cypripedium 

 a. Anther 1, terminating the column (the two anther-cells should not be mistaken 

 for separate anthers) ; labellum flat or concave, but not moccasin-shaped. 

 b. Flowers spurred. 

 c. Glands of the two pollinia convergent, contained in the same pouch over the 



stigma; lip white, spotted; petals and sepals purple. 2. Orchis 



c. Glands of the two pollinia divergent, widely separated on either side of the 

 stigma; perianth concolorous. 3. Habenaria 



/;. Flowers not spurred, at most merely saccate-ventricose. 



c. Flowers large (perianth 1.5-4.5 cm. long) ; column moderately or much 

 elongated. 

 d. Leaves linear, or reduced to sheaths only ; flowers pink or purple. 

 e. Flowers few in a raceme ; perianth not gamophyllous, apparently inverted 

 (really straight, since orchid flowers are normally inverted) with the 

 labellum uppermost. 7. Calopogon 



e. Flowers solitary, terminal ; perianth gamophyllous, apparently not in- 

 verted, ringent. 8. Arethusa 

 d. Leaves elliptical or oval. 



e. Flowers racemose, pink; column not denticulate at apex; anther erect; 

 pollen grains compound, pitted; subterranean parts tuberous and sub- 

 stoloniferous. 4. Triphora 



e. Flowers solitary, rarely 2, pink or brownish; column denticulate at apex; 

 anther incumbent, the loculi facing downward ; pollen grains not pitted ; 

 tubers and stolons wanting. 

 /. Leaf solitary; sepals equaling the lip; pollen grains simple. 



5. Pogonia 

 /. Leaves whorled ; sepals narrow, much exceeding the lip ; pollen grains 

 compound. 6. Isotria 



c. Flowers smaller (perianth 1 cm. long or less), few or many, never normally 

 solitary ; column short or moderately elongated. 

 d. Green foliage present at flowering time; stem green; flowers white, green, 

 or brown. 



9 Natural synopses in this family are based on column and pollen characters, and are difficult to 

 use unless the material is in first-class condition and the operator is skilled. 



