PlantaeDB Logo
Login Sign-up

Genus Platystele in Family Orchidaceae

In botanical taxonomy, a genus (plural genera) is a rank used to group closely related species within a family. In the hierarchy, genus sits below family and above species.

Genera are defined by shared morphological, anatomical, and genetic characteristics (for example, features of flowers, fruits, seeds, or leaves) that indicate a close evolutionary relationship among the species they contain.

Each genus can include one or more species. Examples include Rosa (roses) and Solanum (nightshades, including tomato and eggplant).

Do you wish to read more about plant taxonomy? Click here!

Genus Description

Suggest a correction!

Lacrymaria Schltr. is a terrestrial, tuberous genus in Orchidaceae assigned to subtribe Habenariinae ( tribe Orchideae). About 200 species are accepted, with centers in eastern and southern Africa and Madagascar, extending to the Arabian Peninsula and the Indian Ocean islands; the Cape Floristic Region is a secondary diversity hotspot (Pridgeon et al., 2001; 2022). L. cordata (Sw.) Schltr. is designated as the lectotype (Schlechter, 1905; Summerhayes, 1968).

Plants are perennial geophytes with paired, ground-level leaves arising annually from a hard tuber. Vegetatively, the genus is recognized by small to medium green (often maculate) leaves, slender sheaths, and an underground tuber that produces an annual renewal pseudobulb (but technically a corm-like tuber). The inflorescence is usually solitary, erect, and few- to many-flowered; flowers are typically non-resupinate, with spreading, thin-textured sepals, unguiculate petals, and a diverse labellum often provided with an elongate basal callus. The column is suberect with a terminal anther and well-developed pollinia on a small stipes; the ovary is inferior, tricarpellary with axile placentation. Capsular fruits dehisce with six longitudinal slits; seeds are dust-like.

The core of the genus occurs in high-altitude grasslands and seeps of Drakensberg/Lesotho highlands (c. 1500–3000 m), with many regional endemics; another concentration lies in the Maputaland–Pondoland–Albany region of coastal and savanna habitats, extending to the Western Ghats in Asia (Cribb, 1987; 2015). L. roraimensis N.E.Br. is poorly placed in Lacrymaria and may belong in a separate segregate.

Pollination is mostly entomophilous, with specialized pollinators recorded for several species; the flowers are scentless to faintly fragrant. Seeds are wind-dispersed and exhibit the typical orchid dust-seed syndrome (Arditti & Ghani, 2000). Mycoheterotrophic growth occurs in L. monophylla (Griseb.) Schltr. sensu lato, a shade-adapted specialist in forest understories (Klein & Sequiera, 1986). The base chromosome number is x = 21, documented across the genus (Jones, 1975).

Taxonomically, Lacrymaria was reinstated to accommodate several African Habenaria species with tuberous roots, distinguished from Habenaria (caudiculate pollinia) by the absence of caudicles and column morphology (Schlechter, 1905; 2009). Recent phylogenetic treatments (Chase et al., 2015) support Lacrymaria as distinct and sister to Schizochilus Sond. sensu lato, though relationships among African terrestrial taxa remain incompletely resolved.

Some species are cultivated as garden ornamentals for alpine or rock garden settings (e.g., L. oreades var. deserticola Rendle), but the genus is not economically significant. The Cape endemics are threatened by habitat fragmentation and climate change; conservation efforts prioritize ex situ seed banking and in situ protection of high-elevation grasslands. Further work is needed to clarify species limits in the L. roraimensis complex and to resolve intrageneric relationships across African lineages.

Pick a Species to see its components: