I shall not seem presumptuous if I venture on a few more remarks.2 When seedvessels are freely exposed to the sun and air they tend to dry up prematurely and the seeds consequently would be apt to be small and so the progeny would stand a chance of being weakly.
If, however, the plant could ⟨draw its see⟩d vessels in⟨to shade⟩ ⟨2 or 3 words⟩ moisture the pod and, what is of more importance, its enclosed seeds would go on swelling much longer than they otherwise would do. In Mr Bentham’s Helianthemums the trick is just being learnt and Mr Bentham tells me this morning that it is his impression that some arrangement of the kind is far from uncommon ⟨in s⟩mall herb⟨aceous plants.⟩3
As a slight illustration I may mention that having put the pods of Amphicarpæa which you gave me in their envelope in my pocket—the warmth of my body caused the desiccation and consequent dehiscence of the aerial pods while the subterranean one was unaffected. The amphicarpic species of Lathyrus—which are all perhaps local races of L. sativus are dry country plants Syria, S. France, Portugal.4 In these the subterranean ⟨pods are⟩ produced from subterranean shoots with cleistogamic flowers which is a most singular arrangement but is an acquired habit as it does not occur in normal L. sativus
However, I am afraid I am guilty of presumption, for all this could not fail to occur to you.
Sir Joseph Hooker suggests Ceratopteris for Saporta’s fossil. This seems a very probable hypothesis The obvious objection is that Ceratopteris having pinnate fronds is not ⟨di⟩chotomous5 ⟨But the⟩
Please cite as “DCP-LETT-5825,” in Ɛpsilon: The Charles Darwin Collection accessed on