362 REV. GEORGE HENSLOW ON THE 
blossoms to be degraded, but differentiated, forms of conspicuous allied ones. Thus 
of Lathyrus Nissolia (p. 826) he remarks that this species “apparently offers a case 
of the first stage in the production of cleistogamous flowers, for on plants growing in a 
state of nature, many of the flowers never expand, and yet produce fine pods. Some of 
the buds are so large that they seem on the point of expansion ; Gen are much smaller, 
but none so small as the true cleistogamic flowers of other species.’ 
Rosace&.—‘“ Our three species of Prunus,” writes Sir John Lubbock (7. c. p. 90), «differ 
somewhat in the relations of the anthers to the stigma. In P. Cerasus (the Cherry) both: 
mature at the same time, while in P. spinosa (the Black Thorn) and P. Padus (the Bird 
Cherry) the stigma reaches maturity before the anthers; though, as it retains the capa- 
bility of fertilisation after the anthers have opened, the flowers are doubtless often self- ` 
fertilised, which, from the position of the anthers, probably happens more frequently 1 Im ` 
the Bird Cherry than in the Black Thorn.” 
This case of Prunus is an interesting one, for it is opposed to.the rule that protero- ` 
gynous flowers are inconspicuous and usually unattractive to insects. The cause of the ` 
species of this genus maturing the pistil early is probably in consequence of their flower- . 
ing early in spring; the temperature not being high, there is no special tendency to 
stimulate the staminal and coronal whorls, or possibly the glands. It has been elsewhere 
shown that flowers, usually perhaps intercrossed, will. become self-fertilizing in cold 
weather; so that what takes place abnormally with proterandrous flowers becomes 
normal in the case of Prunus. The same remarks apply to the Apple and Hawthorn, 
which are proterogynous. ! 
Spireas, if not visited by Bees for pollen —dis they contain no honey—are, without | 
little doubt, self-fertilizing. 
Geum. Though both British species are mellifluous, yet the smaller, G. urbanum, a 
probably mostly self-fertile; for the position of the stamens, arching over the carpels ` 
and dehiscing upon them, is quite in keeping with the small-flowered Ranuneuli, as also ` 
with Potentilla Fragariastrum. As with the Ranunculi, the stamens mature centri- ` 
petally, thus affording a considerable time to elapse, during which the carpels may suc 
cessively mature their stigmas; so that while in the more conspicuously flowering ` 
species, as Geum rivale aud the Blackberry, intercrossing is chiefly effected, it does not 
preclude the possibility of self-fertilization, which probably snpittodpa it Kess im 
the small-flowering more or less inconspicuous flowers. T 
Agrimonia Eupatoria.. In this flower the stamens are spreading on first expansion, 
but it is probably self-fertilizing afterwards, as the anthers become strongly recurved over ` 
the pistil. (See Tab. XLIV. figs. 16 a; 5.) : : 
. Potentilla reptans. This will, I think, illustrate the "deii dn above. The 
corolla is usually from three quarters to one inch in diameter, consequently it is very 
conspicuous and probably usually intercrossed. I found, however, specimens in flower _ 
on the 29th Sept. 1876, with the blossoms not half an inch in diameter; while in some ` ` 
buds unexpanded the pistil was covered with a dense mass of pollen, of which the tubes . 4 
were to be detected penetrating the stigmas. If, then, my interpretation be correct, the ` ` 
inference I would draw is, sad Shin, was a process of EE induced SH the 
