376 REV. GEORGE HENSLOW ON THE 
development is exactly the same as in Geer versicolor, ait appears, like it, to be 
self-fertilizing. 
PRIMULACEH.—This order is most conspieuous for its heterostylism. Primula. Though 
probably the majority of species of this genus are dimorphic, there are some which are 
normally non-dimorphie *. Others, again, have been observed to fluctuate; thus Mr. 
Scott mentions P. pusilla and P. floribunda, both of which are, as far as his observatibli 
went, solely short-styled forms, yet he found an individual of each with stamens and 
pistil of the same length. With regard to the position of the anthers of non-dimorphie 
forms, they may be in either position.—P. scotica. Mr. Scott noticed that in native 
specimens of this species the anthers usually surround the mouth of the corolla-tube, 
while in cultivated specimens they are generally attached about one third of the length | 
of the tube below the orifice; the length of style varies accordingly.—P. sibirica. The 
native variety of this, with oblong entire leaves, was always dimorphic ; but the culti- 
vated specimens of the variety, with ovate crenate leaves, was always non-dimorphic, 
—P. verticillata. In both wild and cultivated specimens the structure is the same, viz. | 
the stamens are attached to the upper third of the tube. The length of the style is sub- 
ject to slight variations. With regard to the fertility of these plants, Mr. Scott found 
that when P. scotica was protected, it produced seeds per capsule in the ratio of 1:2: 24. 
, às compared with the seeds of artificially fertilized flowers. P. mollis greatly exceeded 
all other species which Mr. Scott examined in its * regular self-fertility," inasmuch as 
* nearly every flower produced a capsule filled with good seed." Other non-dimorphie 
species produce “ very generally a high percentage of abortive capsules, together with a- 
great variability in the number of seeds contained in those that do set seed." P. verti- 
cillata, contrary to the preceding, presents an imperfect functional dimorphism in con- 
junction with a non-dimorphie structure. In 1862 this plant proved to be self-sterile; 
but in 1863 “certain of the flowers, fertilized by their own pollen, yielded a considerable 
amount of seed ; " but the relative value of crossing, as compared with self-fertilization, 
appears in the ratio of 4:1. Primula veris is sometimes non-dimorphie, and, according 
to Mr. Scott, is then more fertile than by legitimate unions, thus :—Red cowslip, non- 
dimorphic form, yielded average number of seeds per capsule 34. Do., long-styled des 
do. 28. Do., short-styled form, do. 20 (7. c. p. 106). | 
Primula Sinensis. Mr. Darwin has given details respecting this slant (* Cross and 
Self-fértilization, p. 225), and records that although legitimate unions were more fertile 
than illegitimate, v * there was n difference in growth between the offspring fro 
legitimate and illegitimate union." Mr. Darwin accounts for this by the fact t 
| English plants are commonly raised from self-fertilized seeds; so that, as with 
common Pea, which is habitually self-fertilized, crossing does little good. “ Moreo 
many of the plants are now varying and changing their character, so as to become 
greater or less degree equal-styled, and in eonsequence highly self-fertile " (2. e. p. 225 
‘Such conditions, then, I ev to be reversions to an ancestral equal-styled state ; and 
— * Mr.J. Scott, in a paper on “The Functions and Structure of the Reproductive Organs in the io Donen? 
(Journ. Linn. Soc., Bot. viii. p. 7 8) gives. 36 Tas which are ger 7 msdn d 
ee oue pone 
