Keel. The folded edge or ridge of any structure, alluding to its resemblance to the 

 keel of a boat (fig. 218); in papilionaceous flowers, the two united front petals 

 (fig. 503). 



Key or Key fruit. A winged fruit, like the maples, samara (fig. 620). 



Labia, labiate. Lipped; a member of the Labiatae. 



Lacerate. Torn irregularly. 



Laciniate. Deeply incised into irregular, pointed lobes. 



Lacuna {-ae). An air space in the midst of tissue; said of the vallecular canals of 



Equisetum; a hole or cavity. 

 Lamina {-ae) . The blade or expanded part of a leaf, petal, etc. Laminar: of the 



blade. 

 Lanate. Woolly, with long, intertwined, curled hairs (fig. 785). 

 Lanceolate. Much longer than broad; from a broad base tapering to the apex; 



lance-shaped (figs. 414, 787). 

 La.x. Loose and often scattered; often said of flowers in an inflorescence. 

 Leaflet. A discrete segment of a compound leaf. 

 Legume. A one-celled fruit dehiscent on two sutures; specifically, the fruit of a 



member of the pea family. 

 Lemma. The outer (abaxial) bract subtending a floret in the flower of a grass, 



often chaflfy (figs. 3a, 108). 

 Lenticels. Corky spots on young bark, arising in relation to epidermal stomates. 



Lenticellate: having lenticels. 

 Lenticular. Shaped like a lens, having opposite sides convex (fig. 412). 

 Ligulate. Shaped like a ligule (fig. 741 ). 

 Ligule. An elongate, flattened structure; specifically, in monocotyledons, especially 



grasses, the bractlike emergence from the top of the leaf sheath at the base of 



the blade (fig. 108); in the Compositae, a strap-shaped coroHa (fig. 741). (All 



corollas are ligules in the tribe Cichoreae; in many other Compositae only the 



marginal ray corollas are ligules.) 

 Limb. The spreading part of a sympetalous corolla or synsepalous calyx; usually 



referring only to the corolla lobes (fig. 3b). 

 Linear. Long and slender, with more or less parallel sides (fig. 787). 

 Lip. The upper or lower part of a bilabiate corolla or calyx. 

 Littoral. Of a shore, particularly of the seashore. 



Lobe. An outward projection from the margin of an organ, usually with the mar- 

 gin indented on either side of the projection, as in leaves. 

 Lobed. Characterized by having lobes. 



Locule (loculus). A compartment or cell, such as that of an ovary or anther. 

 Loculicidal. Said of capsules that are dehiscent along the loculus or back of the 



carpels (fig. 789). Compare Septicidal. 

 Lodicule. One of two or three scales at the bottom of the ovary, as in many 



grasses (fig. 3a). 

 Lament. A flat legume that is constricted between the seeds, falling apart at the 



constrictions when mature into one-seeded joints. 

 Lyrate. Lyre-shaped; pinnatifid, with the terminal lobe considerably larger than 



the others. 



Macrosporangium. The organ in which macrospores are produced. 



Male (plant or flowers). Having stamens but no pistils. 



Malpighiaceous hairs. Straight appressed hairs attached by the middle and tapering 



to the free tips. 

 Marcescent. Withering, but remaining attached. 

 Marginal. Of, pertaining to, or attached to the edge. 



1719 



