anti] § THE MECHANISMS OF FLOWERS. 261 
trimorphic species ; Pemphis, Forst., has dimorphic species (Kuhn, 
No. 399, Darwin, No. 167, 2nd ed.). Koehne’ mentions twenty-one 
_heterostylic and 340 homostylic species of Lythrum ; according to 
him, L. thymifolia is not heterostylic (394). Pemphis acidula, 
Forst., and some species of Rotala,» L., and Neswa are clearly 
heterostylic and dimorphic. 
 Amimannia latifolia, L., has cleistogamic flowers (394). 
_ Cuphea silenoides, Nees, C. floribunda, Lehm., and C. Melvilla 
Lindl., according to Treviranus, fertilise themselves before the 
ae 
) ae 
_ flower opens (742). 
Ord. ONAGRARIE &£. 
166. EPILOBIUM ANGUSTIFOLIUM, L.—The markedly proter- 
r undrous flower was thoroughly discussed by Sprengel, who noticed 
humble-bees as its fertilisers. The bright crimson racemes, a foot 
long, are very conspicuous, The honey is secreted by the green, 
fleshy, upper surface of the ovary, and is easily accessible to insects 
and yet well sheltered from rain. The expanded lower ends of the 
filaments form a hollow cone, which incloses the base of the style 
and the surrounding honey; where the style issues at the apex of 
this cone, hairs upon the style prevent the entrance of raindrops, 
while insects easily gain access between the filaments. 
In young flowers the stamens, covered above with pollen, project 
| forwards as an alighting-place for insects, while the style is still 
short and bent downwards, with its stigmas folded together ; in older 
| flowers, the empty stamens are bent downwards, and the style, 
' greatly increased in length, projects forwards with its four stigmas 
outspread and recurved. Alighting, sucking, and pollen-collecting 
are thus all made easy, cross-fertilisation in case of insects-visits is 
insured, and self-fertilisation rendered impossible. In fine weather, 
| sufficient insect-visits are always insured by the conspicuous colour, 
/size, and grouping of the flowers, and by the abundance and 
/accessible position of the pollen and honey. 
: Visitors: A. Hymenoptera—(a) Apide : (1) Apis mellifica, L. $,s., very 
b.; (2) Bombus lapidarius, L. 2 $8; (3) B. pratorum, L. 9? $9 4; (4) B. 
terrestris, L. 2 § 3; (5) B. confusus, Schenck, ?, all ab., s. ; (6) B. agrorum, 
y F 2 & g, very ab.,s.; (7) B. (Apathus) campestris, Pz. ¢, s. ; (8) Sphecodes 
‘\gibbus, L. 9, s.; (9) Nomada Roberjeotiana, Pz. 9, s. ; (10) N. Jacobaxe, 
z. 3, 8.3 (b) Sphegide: (11) Cerceris nasuta, Latr. ; (12) Crabro alatus, Pz. ; 
3) Ammophila sabulosa, L. ; (c) Tenthredinide : (14) Tenthredo scrophularie, 
, all sucking. B. Diptera—(a) Empide: (15) Empis rustica, Fallen ; 
1 Vide Bentham and Hooker, Genera Plantarwm, i. p. 776. 
