Leuenbergeria lychnidiflora

Habitat and flowers

The species occurs from southwestern Mexico to Costa Rica. The embryological paper described it as a tree of tropical deciduous forests. Material was collected from a population in the Guiengola area near Tehuantepec in Oaxaca. Solitary orange flowers develop on leafy shoots. [Jiménez-Durán et al. 2014] [2-WWW]

Leuenberger described young shoots with fleshy pith and primary cortex and fleshy spine bases. Outer tepals are green and thicker, while inner ones are more delicate, orange and fringed. Numerous stamens may obscure the pistil. Differences between perianth parts remain visible after flowering, when thicker tissues retain succulence longer. [Leuenberger 2008]

Plant structure and cultivation conditions

In the description of Mexican material, plants reached 10 m tall, leaves 7 cm long and flowers 6 cm in diameter. Leaves are slightly fleshy and shed seasonally. A solitary orange flower terminates a leafy growth. The older stem region may simultaneously bear short-shoot leaves developing from persistent areoles. [Jiménez-Durán et al. 2014]

Leuenberger summarised 25 years of cultivating this species in a botanical garden. Bringing plants from seed to flowering required a very warm summer and a warm greenhouse even in winter. For collections in Poland, this supports separating it from plants overwintered in a cool, dry cactus house. The author gave no numerical minimum temperature in this account, and leaf loss alone does not demonstrate cold tolerance. [Leuenberger 2008, p. 62]

Pollen and the beginning of seed development

The anther contains four pollen sacs arranged in pairs in two parts. Meiosis produces microspore tetrads. After further divisions, mature pollen contains one vegetative cell and two sperm cells. Grains with three, four or five furrows were observed, with surfaces covered in perforations and small spines. Variation in furrow number occurred in the material examined from the same species. [Jiménez-Durán et al. 2014]

The ovule has two integuments and a strongly developed nucellus. The embryo sac develops from one functional megaspore and follows the Polygonum type. In the maturing seed, endosperm is gradually consumed, while perisperm, derived from nucellar cells, persists. Perisperm stores starch, and the embryo's large cotyledons mainly store proteins. The outer seed-coat layer thickens and contains tannins. Reagents used in the study served for microscopic preparation, so the procedure is not a trial to improve germination. [Jiménez-Durán et al. 2014]

Stomata were found on the surface of the lower and middle parts of the ovary. The authors considered their role in secretion but did not measure their function. The result concerns a floral organ and therefore does not contradict the description of the young Leuenbergeria stem as lacking stomata. Ovary position also depends on the developmental stage assessed. In the study of the stage before flower opening, it was described as inferior. [Jiménez-Durán et al. 2014]