Veronica colostylis

Veronica colostylis from near Arrowtown, New Zealand.

In autumn 2011 I wrote about Lammas flowering, when spring- or summer-flowering plants get fooled by a mild autumn into a second flowering.  This Veronica colostylis is doing just that in a pot at home today, but probably because it was transplanted in February from its home in the Arrow Valley near Queenstown, and it's a bit confused, poor thing.

Veronica colostylis flower (it's about 10 mm diameter).

Veronica colostylis is little more than a small-flowered form of V. linifolia, and in fact when I first described it it was as a subspecies, then under the genus Parahebe: Parahebe linifolia subsp. brevistylis.  Another botanist, Michael Heads, raised it to species rank later (as Parahebe brevistylis), and David Lloyd and I followed that when we published a monograph on Parahebe (Garnock-Jones & Lloyd 2004), and later (Garnock-Jones et al. 2007) when I transferred it to Veronica (it needed a new name because there was already a Veronica brevistylis).

Veronica colostylis in the Arrow Valley, New Zealand

When compared with V. linifolia, it's clear that the differences are quantitative only.  The flowers are a bit smaller, and the stamen filaments and the style are noticeably shorter.  The flowers have a lot less colour, and the short stamens hold the anthers very close to the stigma.  All these are adaptations to self-pollination, and it's no surprise that in the absence of insects, V. colostylis sets seed, while V. linifolia doesn't.

Veronica linifolia from Arthur's Pass, New Zealand.

So what does this mean about the appropriate rank for this plant?  If the differences are only quantitative (smaller parts with just the same structures), then they don't really provide evidence of any breeding barriers between V. linifolia and V. colostylis.  However, I never had much luck trying to cross them.  The only hybrid I managed to raise looked very like V. linifolia, so much so that I wouldn't have trusted it really was a hybrid except that its female parent was V. colostylis.  That hybrid had 37% of its pollen malformed, suggesting that there are genetic differences that lower fertility in crosses between them.  Additionally, the ranges of the two species overlap slightly in Canterbury, without any suggestion that they hybridize or intergrade there, so I'll stick with species status for now.

I saw V. colostylis again last summer, just downstream from the terminal face of the Franz Josef Glacier, New Zealand.

References.

Garnock-Jones, P.J.; Lloyd, D.G. 2004: A taxonomic revision of Parahebe (Plantaginaceae) in New Zealand.  New Zealand Journal of Botany 42: 181–232.

Garnock-Jones, P.J.; Albach, D.; Briggs, B.G. 2007: Botanical names in Southern Hemisphere Veronica (Plantaginaceae): sect. Detzneria, sect. Hebe, and sect. Labiatoides. Taxon 56: 571–582

Not tonight Josephine.

Apparently Napoleon never said "Not tonight Josephine", but it's probably the one thing most people associate with his wife, the Empress Josephine of France (1763–1814).

She should be more widely known instead for having this spectacular climbing plant named in her honour:

Copihue, Lapageria rosea

The Empress was born Josephine Tascher de la Pagerie, and it's from her surname that Lapageria is derived.

Lapageria rosea is the only species, and it's the national flower of Chile, which is where it occurs naturally.  I've been watching this plant in Kelburn, since noting its spectacular flowers.  The flowers are clearly monocot flowers—they have sepals and petals in threes—but take a look at the leaves:

Lapageria leaf, and note the Agapanthus leaf behind, a more typical monocot.

Monocots are supposed to have parallel leaf veins, and these are clearly reticulate (net-like), which is generally characteristic of eudicots and basal angiosperms.  What's going on here?

Judd et al. (2008) explain: "Several monocots have pinnate to palmate leaves with obviously reticulate venation patterns ..., but these are probably reversals associated with life in shaded forest understory habitats".  How do they know this?

There are two possible ways that some monocots could have net-like leaf veins.  First, the groups with net-like veins could be at the base of the monocot family tree, and then we'd interpret their venation as an ancestral dicot-like feature that they've retained. 

Alternatively, they could be derived higher in the family tree of monocots, from ancestors that had parallel veins, in which case we'd infer that there was a shift from net-like to parallel at the base of the monocots, followed by a reversal to net-like higher in the tree.

When we look at a family tree (a phylogeny) of the monocots, it's clear that the second interpretation is the correct one, because these net-veined plants are deeply nested among species with parallel venation.  Indeed, it seems this reversal has happened more than once.  Lapageria is classified in family Philesiaceae among the Order Liliales.  Some other net-veined monocots are also placed in Liliales, such as our native Luzuriaga (Alstroemeriaceae) and supplejack, Ripogonum  (Ripogonaceae).  But net-veined Dioscorea (the true yam, not to be confused with oca, Oxalis tuberosa) is classified in Dioscoreales, so it looks as if they came by their net-veined leaves as a separate event.

Luzuriaga parviflora

It seems the genetic ability to make net-veined leaves might be present in many monocots but silenced in some way, making it relatively easy for reversals to evolve.  There are several well-known mechanisms for this kind of evolution.  (Added 8 July 2011: Here's a great description of how this kind of thing can work)

Lapageria rosea (local name copihue) is the national flower of Chile.  Hanging red flowers from South America, with no landing place for a pollinating bird, are characteristic of hummingbird pollination.  Sadly, we have no hummingbirds in New Zealand.  The plant I've been watching does set fruit, but the fruits seem to fall before the seeds are ripe and it may be that fruits begin to develop even when the flowers haven't been pollinated.  The anthers are close to the stigma, so you'd think it could self-pollinate, but maybe some other mechanism is preventing seed set.  I might put on my bumble-bee suit and try pollinating it by hand.

Inside the flower, showing the 6 anthers close to the stigma.

Reference

Judd, WS; Campbell, CS; Kellogg, EA; Stevens, PF; Donoghue, MJ (2008).  Plant systematics a phylogenetic approach (3rd ed.).  Sinauer, Sunderland MA.