10 



MISC. PUBLICATION 110, U. S. DEPT. OF AGRICULTUKE 



Culm: The jointed stalk or stem, usu- 

 ally hollow save at the nodes, and 

 mostly herbaceous, of a plant be- 

 longing to the grass family (Poa- 

 ceae, or Graminese). The term is 

 also frequently applied to the usu- 

 ally solid stalks of grasslike plants 

 (sedges and rushes). 



Cuneate: Wedge shaped. 



Cupule: A small cup; specifically, the 

 involucre, or cup, of an acorn. 



Cuspidate: Tipped with a sharp and 

 rigid point, or cusp, especially if 

 lance or spear shaped. (Fig. 25, 

 A.) 



ABC 



Figure 25. — Three types 

 of terminal pointing, 

 as in leaves, leaflets, 

 petals, and sepals : 

 A, Cuspidate ; B. Mu- 

 cronate ; C, apiculate 



Cylindric(al): Shaped like a cylinder; 

 elongated, and round in cross sec- 

 tion. Similar to terete. 



Cyme: A flower cluster (often flat 

 topped or convex) in which the cen- 

 tral flowers bloom earliest. (Fig. 

 26.) The inflorescence represented 

 by a cyme is determinate, since the 

 original flowers always come from 

 terminal buds (and the main axis, 

 therefore, of the inflorescence can 

 not continue to develop), although 



Figure 26. — Cymose inflores- 

 cence, as in the Catchfly 

 genus (Silene) 



flowers may subsequently arise from 

 axillary buds lower down oh the 

 stem. 



Cymose: Arranged in cymes; cyme- 

 like. (Fig. 26.) 



Cytology: The science of plant and 

 animal cells, their structure and 

 functions. 



D. b. h.: Diameter breast high (said 

 of trees). 



Deciduous : Falling away ; not persist- 

 ent or evergreen. Said, for exam- 

 ple, of leaves which drop off in 

 autumn or of a calyx and petals 

 which fall before the fruit is 

 formed. 



Decompound: More than once com- 

 pound. 



Decumbent: Reclining on the ground 

 but with the end ascending;' bending 

 horizontally at the base. Said of 

 stems. Decumbent conveys the idea 

 of weakness. 



Decurrent: Extending down or pro- 

 longed upon another part; said es- 

 pecially of leaves whose petioles or 

 blade bases are perceptibly pro- 

 longed along the plant stem, pro- 

 ducing a winged appearance of the 

 latter. 



Decussate: Arranged in pairs at right 

 angles to the next pair immediately 

 above or below, suggesting when 

 looked down upon the form of a 

 Maltese cross. A number of milk- 

 weeds (Asclepias spp.) afford fa- 

 miliar illustrations of decussate 

 leaves. 



Deflexed: Bent or directed abruptly 

 downward. 



Dehiscent: Opening by valves, slits, 

 etc., to discharge the contents. 

 Anther cells dehisce to emit pollen. 



Deliquescent : Literally, dissolving. 

 Said of tree trunks which do not 

 have a well-defined central axis. 



Figure 27. — Deltoid 

 leaf form, as in cer- 

 tain species of as- 

 pen (Populus) 



Thus oaks (Quercus) usually have a 

 deliquescent habit. 

 Deltoid: Deltalike; broadly triangular 

 and shaped like the Greek letter 

 A. (Fig. 27.) 



