24 RUBIACE^. Bouvardia. 



Mag. t. 1854; Liudl. Bot. Reg. xxvi. t. 37. B. Jacquini, HBK. 1. c. 385; DC. Prodr. iv. 

 365; Grav,Pl. Wright, ii. 67. B. qua tern I folia, DC. 1. c. ? B. coccinea, Liuk, Euum. i. 139. 

 B. terni/olia, Schlecht. in Linn. xxvi. 98. B. splendens, Graliam in Bot. Mag. t. 3781. Ixora 

 ternifolia, Cav. Ic. iv. t. 305. /. Americana, Jacq. Hort. Schoenb. iii. t. 257. Ilonstonia coc- 

 cinea, Andr. Bot. Rep. t. 106. — Rocky ground, S. Arizona, &x., Wright, Thurber, Rothrock, 

 Prinrjle, Leiinnon. (Mex.) 



Var. angustifolia. Cinereous-pubemlent or liirtellous : leaves smaller (8 to 18 lines 

 long), !?iibsessile, less veiny, from oblong-lanceolate to almost linear. — B. hirtella & B. angus- 

 tifolia, HBK. 1. c. 384. B. hirtella. Gray, PL Wright, i. 80, ii. 67. — S. W. Texas to Arizona, 

 Wright, &c. (Mex.) 



4, HOUSTONIA, Gronov. (Named by Gronovius, as says Linnaeus, iu 

 memory of Dr. Wm. Houston, who died in Jamaica in 1733.) — Low herbs, 

 or one or two suffrnticnlose (Athmtic- American and Mexican), with heterogone- 

 dimorphous flowers ; the coroHa blue or purple to white, upper face of lobes 

 sometimes puberulous. — L. Hort. Cliif. 35, & Gen. ed. 1 (1737) ; Juss. Gen. 197 ; 

 Gray, Proc. Am. Acad. iv. 313, & Man. ed. 5, 212 ; Benth. & Hook. Gen. ii. 60. 

 Hedyotis in part (Wight & Arn.), Torr. & Gray, Fl. ii. 3G. (^Macrohoustonia, 

 Gray, Proc. Am. Acad. iv. 314, is a jieculiar group of Mexican species, between 

 this genus and Bouimrdia.^ 



■ § 1. EuHOUSTONiA. Low lierbs, comparatively small-flowered : leaves not 

 rigid : cajisule more or less didymous or emarginate, sometimes seiiticidal as well 

 as loculicidal across the broad summit. 



* Delicate species, inch to span high: corolla salverform: anthers or !?tigmas iucludecl or only par- 

 tially emerging from the throat: peduncles single, elongated and erect in fruit: seeds rather few 

 acetabuliforni with a deep hilar cavity: stipules a transverse membrane uniting the petioles, 

 mostly entire or truncate and naked. 



+— Perennial l)y delicate liliform creeping rootstoclvs or creeping stems: peduncles filiform, incli or 

 two long: seeds subglobose with orifice of the deep hilar cavity circular. 



H. caerulea, L. (Bluets of the Canadians, Ixnocence.) Perennial by slender rootstocks, 

 forming small tufts, erect, a span or more high, glabrous, and with lower leaves liisi>idulous : 

 these spatnlate to obovate and short-petioled ; upper small and nearly sessile : corolla violet- 

 blue to lilac, varying to white, with yellowish eye ; tube (2 or 3 lines long) much exceeding 

 calyx-lobes, longer than or equalled by those of corolla : capsule obcordate-depressed, half 

 free. — Spec. i. 105 (Moris. Hist. sect. 15, t. 4, f. 1 ; Pluk. Aim. & Mant. t. 97, f. 9) ; Sims, 

 Bot. Mag. t. 370; Barton, Fl. Am. Sept. t. 34, f. 1. H. pusilla, Gmel. Syst. i. 23a ? H. Lin- 

 mei, var. elatior, Michx. Fl. i. 85. H. serpyllifolia, Graham, Bot. Mag. t. 2822, from habitat 

 and figure, but corolla-tube too sliort. Hedi/otis aerulea, Hook. Fl. i. 286 ; Torr. & Gray, 

 Fl. ii. 38. H. gentianoides, Endl. Iconogr. t. 89. Oldenlandia ccertdea, Gray, Man. ed. 2, 174. 

 — Low and grassy grounds, Canada to Micliigau and tlie upper country of Georgia and 

 Alabama ; fl. early spring. 



H. serpyllifolia, Michx. Perennial by prostrate extensively creeping and rooting fili- 

 form stems, and some subterranean ones, glabrous or slightly and minutely hispidnlous 

 below: leaves orbicular to ovate or ovate-spatiilate (2 to 4 lines long) and abruptly petioled, 

 or upper ones on flowering stems oblong and nearly sessile : corolla deep violet-blue, ratlier 

 larger than in //. ccerulea. — Fl. i. 85 ; Pursli, Fl. i. 106. //. tenella, Pursli, 1. c. Iledj/otis 

 serpi/llifolia, Torr. & Gray, Fl. ii. 39. Oldenlandia serpijllifolia, Gray, Man. ed. 2 ; Chapm. 

 Fl. 180; — Along streamlets and on mountaiii-tojis in tiie Alleghanics, from Virginia to 

 Tenn. and S. Carolina ; flowering tlirongh early summer. 



■*"" '^~' Winter-annuals, branching from the simple root, glabrous or obscurely scabrous: pedun- 

 cles a quarter-inch to at length sometimes an inch long: capsule somewhat didymous, less than 

 half free: mature seeds generally as of the preceding. 



H. patens. Ell. An inch to at lengtli a sjian higli, with ascemling branches and erect pe- 

 duncles : leaves spatnlate to ovate : corolla much smaller than that of //. ca'ridea ; tlie tube 

 twice the length of the calyx-lobes ajod more or less longer tlian its lobes, violet-blue or pur- 



