16 



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



flower (perianth), showing a close 

 relationship to lilies. Sedges have 

 3-ranked leaves and usually solid 

 stems which are often triangular in 

 cross section. The floral organs of 

 sedges are in the axils of 2-ranked or 

 spirally imbricated (i. e., more or 

 less overlapping) scales and, in the 

 case of the largest and most familiar 

 genus, Carex, the pistillate (female) 

 flower is enveloped in a sac called 

 the " perigynium." Because the 

 majority of rushes and sedges grow 

 in wet sites, grasslike plants are 

 sometimes called " marsh grasses " 

 or "wet meadow grasses." The 

 term "grasses" for them, however, 

 is inaccurate and misleading. 



Gymnosperm : Literally, naked seed. 

 A member of the Gymnospermse, one 

 of the two main groups into which 

 flowering, or seed-producing, plants 

 are customarily divided, the other 

 being the Angiospermee. Gym- 

 nosperms (to which pines and other 

 conifers belong) have the ovules and 

 seeds borne on a naked scale; an 

 enveloping ovary, as well as a true 

 floral envelope (perianth) and 

 stigmas are wanting. Botanically 

 gymnosperms are a primitive and 

 relatively rather small group, but 

 economically they are of the highest 

 importance — to the forester probably 

 the most important of all. 



Gynaecandrous: A term applied to 

 those sedges (Carex spp.) which 

 have male and female flowers in 

 the same spike but the upper flowers 

 female, so that only the upper part 

 of the spike bears 

 fruit. The con- 

 verse of androgy- 

 nous. 



Habit : Aspect ; man- 

 ner of growth. 



Habitat: The site or 

 environment which 

 a plant or plants 

 (as well as ani- 

 mals) natively oc- 

 cupy, and the 

 study of which is 

 the science of ecol- 

 ogy. 



Halophyte: A plant 

 adapted to exist- 

 ence in a saline 

 environment, as 

 greasewood, salt 

 grass (Distichlis), 

 and the saltbushes 

 (Atriplex spp.). 



Hastate: Shaped like a spear or hal- 

 berd head, the basal lobes pointing 



Figure 34. — Has- 

 tate leaf of 

 sheep sorrel 

 (Rumex aceto- 

 sella) 



outward and usually much shorter 

 than the blade. (Fig. 34.) 



Haw: A hawthorn (Crataegus sp.) or, 

 more especially, its fruit; a small 

 pome, or hip, as in a rose. This 

 form of fruit is caused by the fleshy 

 enlargement of the hypanthium. 



Head: A headlike formation, especially 

 a rounded, congested inflorescence 

 or seed cluster; the characteristic 

 inflorescence of the aster,* or com- 

 posite family (Asteracese, or Com- 

 positse). In a true head (capitu- 

 lum) the individual flowers are ses- 

 sile or nearly so. 



Helicoid: Shaped like the spirally 

 coiled shell of a snail (Helix). 

 (Fig. 35.) 



Heliotropism : Response in a plant to 

 the stimulus of sunlight; the turn- 

 ing or growth of the 

 aerial portion of a 

 plant to light ema- 

 nating from the sun 

 (Greek, helios) ; as 

 in the radicle and 

 plumule of the em- 

 bryo. 



Hemi -: A prefix 

 (Greek) signifying 

 half. 



Herb: A phanerogam 

 (flowering plant), 

 the aerial portion 

 of whose stem is 

 destitute of woody tissue and per- 

 ishes when flowers and fruit are 

 matured. An herb may have an an- 

 nual, biennial, or perennial root, 

 but the aerial stem is ordinarily 

 annual ; when a stem survives into 

 the second or ensuing seasons there 

 is naturally a tendency for woody 

 tissue to form and for the transition 

 to shrub or tree status to ensue. 



Herbaceous: Of or pertaining to herbs; 

 having the characteristics of an herb 

 and free from woody tissue. 



Hermaphrodite: A word (both noun 

 and adjective) used to describe an 

 individual having the organs, char- 

 acteristics, qualities, or attributes 

 of both sexes. Said specifically, in 

 botany, of a perfect flower, i. e., one 

 containing both pistils and stamens. 



Heterogenesis: Same as alternation of 

 generations. 



Hexamerous: Having the parts in 

 sixes (Greek, hex, six, + meros, 

 part). 



Hilum: The scar on the surface of a 

 seed which shows the place of de- 

 tachment of the matured ovule from 

 its base or seed stalk. 



Hirsute: Hairy with rather coarse, 

 stiffish, straight, beard like hairs. 



Figure 35. — 

 Helicoid 

 pod of al- 



alfa 



