HYDRQPYRUM 335 



In autumn large buds are formed on the stolons and drop off to winter 

 at the bottom. In spring they float up and develop into new pis. 



Hydrocharitaceae (Ef\, BH.}. Monocots. (Helobieae; Microspermae 

 BH.). 13 gen., 65 sp. trop. and temp., all water pi., some marine 

 (Halophila, Enalus, Thalassia). Most have ribbon-like submerged 

 1., a few have floating 1. (Hydrocharis, &c.); some have 1. projecting 

 above the water. In the leaf-axils are 'squamulae intravaginales ' 

 ((/. Potamogetonaceae). Several buds are frequently found in one 

 leaf-axil. 



Sexes usu. in different fls., commonly on different plants. Infl. 

 axillary, usu. i -flowered when ? , often more than i if <? , enclosed at 

 first in a spathe of two or more (i in Hydrocharis?) fused 1. Fl. 

 usu. reg., 3-merous. P usu. in two whorls, the outer sepaloid, the 

 inner petaloid; sta. in i 5 whorls, the innermost often staminodial; 

 G (2 15), i-loc. with parietal plac. ; ovules oo, ortho- to ana-tr., 

 erect to pend. ; stigmas as many as cpls. Fr. irreg. dehisc., containing 

 ooexalb. seeds. Chief genera: Halophila, Elodea, Vallisneria, Stra- 

 tiotes, Hydrocharis. 



Hydrochloa Beauv. Gramineae (6). r S.E. U.S. 



Hydrocleys Rich. Butomaceae. i Brazil, H. nymphoides Buchenau, 

 a water pi. with striking resemblance to Nymphaea or Limnanthemum. 

 Cult. orn. fl. 



Hydrocotyle (Tourn.) L. Umbelliferae (n. i). 70 trop. and temp. 

 i in Brit., H. vulgaris L. (white-rot or pennywort), easily recognised 

 among native U. by its peltate 1. 



Hydrolea L. Hydrophyllaceae. 1 2 trop. Several have axillary thorns 

 (branches). Fl. self-fertilising (cf. Phacelia). 



Hydrolirion Leveille. Hydrocharitaceae. t Corea. 



Hydrolytnrum Hook. f. (Rotala p.p. EP.}. Lythraceae. i Indomal. 



Hydromystria G. F. W. Mey. (Limnobium p.p. BH.). Hydrochari- 

 taceae. 3 trop. Am. Cult. orn. fl. 



Hydrophylax L. f. Rubiaceae (n. 10). 3 coasts of Ind. Ocean. 



Hydrophyllaceae (EP. , H.}. Dicots. (Sympet. Tubiflorae ; Pole- 

 moniales BH.}. 17 gen. 170 sp., chiefly in N. Am.; a few in S. Am., 

 trop. As., Afr., &c. Herbs or undershrubs with simple or cpd. 

 exstip. L, radical, alt. or opp. Plant usu. hairy. Fls. scattered or in 

 cincinni like those of Boraginaceae, usu. without bracteoles, , reg., 

 usu. 5-merous. K (5), imbr., the odd sepal post.; C (5), rotate, or 

 bell- or funnel-shaped, usu. imbr.; A 5, epipet. and alt. with pets., 

 often with scale-like appendages at base (see below); G (2), i 2-loc., 

 with i or 2 styles; ovules on each cpl. oo 2, sessile or pend., anatr. 

 Fr. usu. a loculic. caps. Embryo small, in rich endosp. The fls. are 

 visited chiefly by bees ; honey is secreted below the ovary and pro- 

 tected by the appendages of the sta., which are frequently united to 

 the corolla, sometimes (Hydrophyllum) forming tubes leading down 

 to the honey. Fl. usu. protandrous. See Phacelia. Chief genera: 

 Hydrophyllum, Nemophila, Phacelia, Nama, Hydrolea. 



Hydrophyllum L. Hydrophyllaceae. 6 N. Am. Fl. protandrous, 

 with the staminal appendages united to the corolla so as to form tubes 

 through which alone the honey is accessible. 



Hydropyrum Link = Zizania Gronov. (Gramin.). 



