NYCTAGINACEÆ. 11 
the globe! Their bark is spongy; their branches often thorny. 
Their leaves are alternate or opposite, simple, entire, glabrous 
and exstipulate. Their flowers are in simple or ramified racemes, 
generally composed of cymes, sometimes umbelliferous or corymbi- 
ferous, terminal, lateral, or inserted upon the wood of the stem 
or branches. Each flower is accompanied at its base by small 
bracts, generally two or three, more rarely from four to six, in 
number. 
In Colignonia’ the inferior part of the perianth forms an ovoidal 
purse, enveloping the ovary with a narrow opening, beyond which 
it dilates into a bell-shaped limb, with three or five valvate lobes. 
The androceum is formed of five or six hypogynous stamens, more 
or less exserted ; and the gynæceum, inserted quite at the bottom of 
the flower, has a glabrous uniovular ovary surmounted by a style, 
stigmatiferous and capitate papillose, or penicillate at the apex. 
The fruit is an achene enveloped by the entirely persistent perianth. 
Its inferior portion is dilated into a kind of sac, with three or four 
vertical wings. The three or four species’ of this genus are her- 
baceous or suffrutescent plants, with very small and very numerous 
flowers, disposed in simple or ramified racemes of cymes, often 
umbelliferous, sometimes accompanied by bracts or modified petaloid 
leaves. They inhabit all western tropical America. 
Boldoa has a tubular perianth, analogous to that of certain 
Pisonias, and separated above into four valvate or induplicate teeth. 
At the bottom is found a gynæceum, surmounted by along subulate 
style, and three or four bypogynous exserted stamens. Three or 
four species have been described, of which the best known is 
Mexican.’ The others are from the neighbouring regions, herbaceous 

1 L., Spec., 1511.—Sw., Prodr., 60; Fl. 
3H. B. K., Nov. Gen. et Spec., ii. 216, 
Ind. Oce., 643, 1960.—H. B. K., Nov, Gen. t. 
128 (Abronia). — SPRENG., Syst., i. 536 
et Spec., ii. 217.—R. Br, Prodr. Fl. Nov.- 
Holl,, 422.—ENDtz., Prodr. Fl. Norfolk, 43. 
—BL., Bijdr., 7135.—GUILLEM., Zeph. Tait. 39. 
—Detess., Jc. Sel, iii. 51, t. 87.—Papp. et 
Expz., Nov. Gen. et Spec., 45, t. 161, 162 
(Neea)—Casar., Dec. Pl. Bras, viii. 69.— 
Link, Kt. et Ort., Pl. Hort. Berol., 37, t.15.— 
Link, Enum., i, 354. —BENTE., Pl. Hartweg.,n. 
381.—NETTO, in Ann. Sc. Nat., sér. 5, v. 80, 
t. 7, 8.—WAtLP., Ann., i 561; iii. 2985 v. 722. 
2 ENDL., Gen., n, 2001,—Cuorts., Predr., 439, 
neal’. 
(Tricratus)—BrEntu., Pl, Hartweg., 148, n. 
628. 
1 Cav., Cat. Hort. Matrit. (1803), t. 7 
(nee J.).—Lag@asc., Diagn., 10.—Cuots., Prodr., 
438.—Salpianthus H. B., Pl. Æquin., i. (1805), 
155.— Enpt., Gen., n. 2010. 
5 SPRENG., Syst., i. 179.—H. B. K., Nov. 
Gen. et Spec. ii, 218.—Porr., Dict., Suppl. 
v. 23; Jll., Suppl., cent. 10, ic.—Marr. et GAL, 
in Bull, Acad. Brux., x. n. 4, 16.—BENTH., 
Voy. Sulph., Bot., 155. 
