Chaste trees and jumping spiders

Yesterday at the Gamble Garden in Palo Alto, a plant note and an animal note: chaste trees and jumping spiders.

Chaste trees. I noticed an attractive large shrub or small tree (multi-branched, in any case) that I’d somehow missed before. It was clearly just past its blooming season, and now I’m sorry I missed its flowering, since it’s a very pretty plant. The chaste tree, Vitex agnus-castus:


From Wikipedia:

Vitex agnus-castus, also called vitex, chaste tree, chasteberry, Abraham’s balm, lilac chastetree, or monk’s pepper, is a native of the Mediterranean region. It is one of the few temperate-zone species of Vitex, which is on the whole a genus of tropical and sub-tropical flowering plants. Theophrastus mentioned the shrub several times, as agnos (άγνος) in Enquiry into Plants. Vitex, its name in Pliny the Elder, is derived from the Latin vieo, meaning to weave or to tie up, a reference to the use of Vitex agnus-castus in basketry. Its macaronic specific name repeats “chaste” in both Greek and Latin … [The plant was] considered to be sacred to the goddess Hestia/Vesta.

… It has been long believed to be an anaphrodisiac [hence “chaste tree”] but its effectiveness remains controversial. [It has other, somewhat less controversial, medicinal uses.]

Vitex agnus-castus is widely cultivated in warm temperate and subtropical regions for its delicate-textured aromatic foliage and butterfly attracting spikes of lavender flowers in late summer in cooler climates.

Vitex was formerly classified in the Verbenaceae (a family I haven’t discussed before), but has been moved to the Lamiaceae, the labiates. So I’ll take this chance to say a few things about the verbena family. From Wikipedia:

The Verbenaceae … are a family, commonly known as the verbena family or vervain family, of mainly tropical flowering plants. It contains trees, shrubs, and herbs notable for heads, spikes, or clusters of small flowers, many of which have an aromatic smell.

Some notable plants in the family: Lemon verbena (Aloysia triphylla), grown for aroma or flavoring; Verbenas or vervains (Verbena), some used in herbalism, others grown in gardens; lantanas or shrub verbenas (Lantana), grown as ornamentals. Here I’ll talk about the last two.

Verbena (…, vervain) is a genus in the family Verbenaceae. It contains about 250 species of annual and perennial herbaceous or semi-woody flowering plants. (Wikipedia link)

Verbenas are notably drought-tolerant and sun-loving. There are many gorgeous hybrids, for instance this assortment:


Lantanas are widely grown as container plants and hanging basket plants, but in warm-enough zones they can be grown as sprawling low shrubs. Here in containers:


In semitropical and tropical areas, they can become invasive weeds; they are a pest in Hawaii, for instance. And therein lies a sad story. From Wikipedia:

Lantana is a genus of about 150 species of perennial flowering plants in the verbena family, Verbenaceae. They are native to tropical regions of the Americas and Africa but exist as an introduced species in numerous areas, especially in the Australian-Pacific region. The genus includes both herbaceous plants and shrubs growing to 0.5–2 m (1.6–6.6 ft) tall.

Some species are invasive, and are considered to be noxious weeds, such as in South Asia, Southern Africa and Australia. In the United States, lantanas are naturalized in the southeast, especially coastal regions of the Carolinas, Georgia, Florida, and the Gulf Coast.

The spread of lantana is aided by the fact that their leaves are poisonous to most animals and thus avoided by herbivores, while their fruit is a delicacy for many birds, including the Yellow-fronted White-eye of Vanuatu, the Superb Fairy-wren in Australia, the Scaly-breasted Munia, and the Mauritius Bulbul in the Mascarenes; these distribute the seeds and thereby unwittingly contribute to the degradation of their home ecosystem.

Jumping spiders. During breakfast at GG, we were afflicted, in a modest way, by creatures, mostly ants, but also quite a few little spiders, which apparently dropped from the tree above us. I recognized the spiders as jumping spiders, from their remarkable eyes (see below) and, yes, their inclination to jump about in an entertaining way.

I’ve posted once before about jumping spiders, specifically the peacock spiders (genus Maratus), of which several new Australian species were discovered not long ago. On the family, from Wikipedia.

The jumping spider family (Salticidae) contains more than 500 described genera and about 5,000 described species, making it the largest family of spiders with about 13% of all species. Jumping spiders have some of the best vision among arthropods and use it in courtship, hunting, and navigation. Although they normally move unobtrusively and fairly slowly, most species are capable of very agile jumps, notably when hunting, but sometimes in response to sudden threats or crossing long gaps.

… Jumping spiders are generally recognized by their eye pattern. All jumping spiders have four pairs of eyes with one pair being their particularly large anterior median eyes.


… Jumping spiders are generally diurnal, active hunters.

… Salticidae are adapted to detailed, three-dimensional vision for purposes of estimating the range, direction, and nature of potential prey, permitting the spider to direct its attacking leaps with great precision.

They also use draglines of silk to move around.

Jumping spiders have lots and lots of fans.

Leave a Reply

%d bloggers like this: