Dear Sir

Tempted by the kindness of your reply to my previous note, I venture to send you by this post my notes made during the past winter & spring on the fertilization of certain plants flowering at those seasons of the year, with the accompanying drawings.¹ I should not think of publishing the observations as a series until they have extended over a much wider range, or I have had the opportunity of confirming them by a second series;² but it would be a great assistance to me if the accuracy of any of them were tested by an independent observer; & I venture to hope you may be able to give me some valuable advice as to the best direction in which to prosecute them, or even as to whether any scientific end will be gained by following them.

My observations so far have led me to the following conclusions (subject of course to correction from a wider series of observations) as to the different classes into which winter-flowering plants may be divided.

1. Those which flower & fructify abundantly through the whole year equally in Dec. & Jan to the summer. These I find to be self-fertilized & generally in the lead at whatever time of the year they flower; & this I take to be the circumstance which adapts them to so long a period of flowering not requiring insect-agency for their fertilization, e.g. Lamium album, Veronica Buxbaumii, Euphorbia Poplus.³

2. Those which normally flower in the spring; but in mild seasons are found not infrequently in the winter; these are cross-fertilized; e.g. Sinapis arvensis, Fumaria officinalis ⁴

3. Very early spring-flowering plants; these are generally either showy or scented, attracting the earliest spring insects, & are cross fertilized. e.g. Viola odorata, Galanthus nivolis.⁵

4. Plants flowering in the depth of winter, but natives of warmer climates, where there are probably plenty of insects in the winter; these are cross-fertilized; e.g. Chimonanthus fragrans & Eranthis hyemalis where the provisions for crossing are even more perfect that in Parnassia, & which appears never to fructify in our gardens.⁶

The most interesting observations to myself have been those on the three species of Euphorbia, Peplus, Heliscopia, & amygdaloides; the two former, genuine winter-flowering plants being apparently self-fertilized, i.e. the pistil from the stamens in the same head of flowers; while in the latter, which never flowers before April, the pistil appears to be fertilized from the male heads of flowers.⁷

You will find Eranthis hyemalis, the Christmas Rose⁸ among the plants in which some observations have been made

I am specially curious about the fertilization of Ruscus.⁹ In most unisexual winter flowering plants, e.g. Corylus avellana,¹⁰ there appears to be special provision for fertilization in the enormous preponderance of male flowers over female, & the manner in which the former are hung, so that the pollen is freely dispersed in clouds by every breath of wind. In the Ruscus on the contrary, which is generally considered to be diœcious, there appears to be no such preponderance, & the excessively rigid stems, growing under the shelter of shrubs & under-wood, would seem to be peculiarly inaccessible to the action of the wind. I found abundance of flowers out last winter in the Surrey heaths during the last week of December, & there were a fair number of the previous year’s berries still remaining on the female plants.

I should be much obliged if you would kindly return the notes & drawings when you have had leisure to glance over them, & must really apologize for troubling you with so long a letter as this

& remain | yrs respectfully | Alfred W. Bennett

C. Darwin Esq