Noticing Nature #9 : Horsetails and Beans

Wednesday 5 November

This week we get down to start the Flowering Plants - starting with a very old plant group indeed …

---

Horsetails (Equisetidae)

These are “living fossils” that have been in the world seemingly for ever. They are unique in being a genus of vascular plants that reproduce by spores, like ferns, rather than seeds.

Their family, of which today’s species are the only surviving relics can be traced back over 100 million years to when they grew in late Paleozoic forests when some were large trees reaching to 100ft tall. Modern horsetails first appeared during the Jurassic period.

The Horsetails grow in wet areas, with whorls of needle-like branches radiating at regular intervals from a single vertical stem. In shaded and damp areas of your garden you may well have some popping up. They are related to the ferns (Polypodiopsida) of which they form a specialized lineage. The division between the horsetails and the other ferns is, however, so ancient that many botanists, especially paleobotanists, still regard this group as fundamentally separate. The line split off in the Devonian period some 350 to 420 million years ago … botanical dinosaurs.

The two members of this group you are most likely to see where I am are the “classical” Wood Horsetail (Equisetum sylvaticum) and also some specimens of Sensitive Fern (Onoclea sensibilis) which is sensitive to frosts. It is often sold for planting near garden ponds from which it happily spreads so long as the soil never dries out. It spreads by rhizomes, and can do so a little too successfully if grown in favourable conditions.

Sensitive Fern

Wood horsetail

Field horsetail

---

Family Fabaceae - Beans

Also known as Leguminosae - this is the plant family that includes the many peas and beans. Some are agricultural species that we eat but many, perhaps most, are just growing outside where we can trample them on walks or mow them if they dare to pop up their heads on our lawns.

Of the wild bean plants, perhaps the most readily identifiable are the four species of clovers that grow here. These are Red Clover (Trifolium pratense), White Clover (Trifolium repens), Sweet White Clover (Melilotus albus) and Alsike Clover (Trifolium hybridum). The last of those, Alsike Clover, was once thought to be a red/white clover hybrid as it exhibits both colours, but it is now known to be a species in its own right. All the clovers are valuable as forage for cattle and even more valuable as nectar producing plants for insects of many species. White and red Clovers are native to Europe and Asia but have been so long established in North America that they are so well naturalized as to be considered native today. Alsike Clover is similarly an arrival from foreign parts. The tall White Sweet Clover may not even be thought to be a clover at first glance. Unlike the low clovers it can reach the height of your chest and its flowers are small white florets on long spikes, but a clover it is and also one that originated abroad.

Alsike Clover and Sweet White Clover

There are two low growing species in this family that will readily grow and spread on your lawn if you avoid mowing for a few weeks. Both have attractive yellow flowers that seem to Appel to butterflies. These are Black Medick (Medicago lupulina) and Bird’s-foot Trefoil (Lotus corniculatus)

Black Medick

Other species include the Narrow-leaved Everlasting-Pea (Lathyrus sylvestris), Tufted Vetch (Vicia cracca) and Black Locust (Robinia pseudoacacia). The latter of those three you may not even consider to be a relative of the humble pea as it grows as a woody tree or shrub bearing delightful white flowers.

Tufted Vetch

There are other Fabaceae species that are native to this continent such as some Acacia, the Redbud tree and the Smokebush but unless carefully cultivated this far north they mostly do not thrive here as established wild species.

---

Next week : Roses

• You will be amazed just how diverse roses are

---